@@ -14,13 +14,13 @@ toolset for the full Ada programming language.
It documents the features of the compiler and tools, and explains
how to use them to build Ada applications.
-GNAT implements Ada 95, Ada 2005, Ada 2012, and Ada 202x, and it may also be
-invoked in Ada 83 compatibility mode.
-By default, GNAT assumes Ada 2012, but you can override with a
-compiler switch (:ref:`Compiling_Different_Versions_of_Ada`)
-to explicitly specify the language version.
-Throughout this manual, references to 'Ada' without a year suffix
-apply to all Ada versions of the language, starting with Ada 95.
+GNAT implements Ada 95, Ada 2005, Ada 2012, and Ada 2022. You may
+also invoke it in Ada 83 compatibility mode. By default, GNAT assumes
+Ada 2012, but you can use a compiler switch
+(:ref:`Compiling_Different_Versions_of_Ada`) to explicitly specify the
+language version. Throughout this manual, references to 'Ada' without
+a year suffix apply to all versions of the Ada language starting with
+Ada 95.
What This Guide Contains
========================
@@ -130,10 +130,10 @@ in this guide:
and then shown this way.
-* Commands that are entered by the user are shown as preceded by a prompt string
+* Commands that you enter are shown as preceded by a prompt string
comprising the ``$`` character followed by a space.
* Full file names are shown with the '/' character
as the directory separator; e.g., :file:`parent-dir/subdir/myfile.adb`.
If you are using GNAT on a Windows platform, please note that
- the '\\' character should be used instead.
+ you should use the '\\' character instead.
@@ -17,8 +17,8 @@ Elaboration Order Handling in GNAT
.. index:: Order of elaboration
.. index:: Elaboration control
-This appendix describes the handling of elaboration code in Ada and GNAT, and
-discusses how the order of elaboration of program units can be controlled in
+This appendix describes the handling of elaboration code in Ada and GNAT and
+discusses how you can control the order of elaboration of program units in
GNAT, either automatically or with explicit programming features.
.. _Elaboration_Code:
@@ -36,7 +36,7 @@ initializing data. These sections are referred to as **elaboration code**.
Elaboration code is executed as follows:
* All partitions of an Ada program are executed in parallel with one another,
- possibly in a separate address space, and possibly on a separate computer.
+ possibly in a separate address space and possibly on a separate computer.
* The execution of a partition involves running the environment task for that
partition.
@@ -71,8 +71,9 @@ In addition to the Ada terminology, this appendix defines the following terms:
* *Target*
- A construct elaborated by a scenario is referred to as *elaboration target*
- or simply **target**. GNAT recognizes the following targets:
+ A construct elaborated by a scenario is referred to as an
+ *elaboration target* or simply a **target**. GNAT recognizes the
+ following targets:
- For ``'Access`` of entries, operators, and subprograms, the target is the
entry, operator, or subprogram being aliased.
@@ -188,7 +189,8 @@ factors:
* invocations performed in elaboration code
-A program may have several elaboration orders depending on its structure.
+A program may have several possible elaboration orders depending on
+its structure:
.. code-block:: ada
@@ -256,7 +258,7 @@ Ada states that a total elaboration order must exist, but it does not define
what this order is. A compiler is thus tasked with choosing a suitable
elaboration order which satisfies the dependencies imposed by |with| clauses,
unit categorization, elaboration-control pragmas, and invocations performed in
-elaboration code. Ideally an order that avoids ABE problems should be chosen,
+elaboration code. Ideally, an order that avoids ABE problems should be chosen,
however a compiler may not always find such an order due to complications with
respect to control and data flow.
@@ -277,7 +279,7 @@ provides three lines of defense:
* *Dynamic semantics*
- Dynamic checks are performed at run time, to ensure that a target is
+ Dynamic checks are performed at run time to ensure that a target is
elaborated prior to a scenario that invokes it, thus avoiding ABE problems.
A failed run-time check raises exception ``Program_Error``. The following
restrictions apply:
@@ -304,7 +306,7 @@ provides three lines of defense:
* *Elaboration control*
- Pragmas are provided for the programmer to specify the desired elaboration
+ Ada provides pragmas for you to specify the desired elaboration
order.
.. _Controlling_the_Elaboration_Order_in_Ada:
@@ -312,12 +314,12 @@ provides three lines of defense:
Controlling the Elaboration Order in Ada
========================================
-Ada provides several idioms and pragmas to aid the programmer with specifying
-the desired elaboration order and avoiding ABE problems altogether.
+Ada provides several idioms and pragmas to aid you in specifying your
+desired elaboration order and avoiding ABE problems.
* *Packages without a body*
- A library package which does not require a completing body does not suffer
+ A library package that does not require a completing body does not suffer
from ABE problems.
.. code-block:: ada
@@ -391,9 +393,9 @@ the desired elaboration order and avoiding ABE problems altogether.
body of Server
spec of Client
- because the spec of ``Server`` must be elaborated prior to ``Client`` by
- virtue of the |with| clause, and in addition the body of ``Server`` must be
- elaborated immediately after the spec of ``Server``.
+ because the spec of ``Server`` must be elaborated prior to
+ ``Client`` by virtue of the |with| clause and the body of ``Server``
+ must be elaborated immediately after the spec of ``Server``.
Removing pragma ``Elaborate_Body`` could result in the following incorrect
elaboration order:
@@ -420,7 +422,7 @@ depend on.
* *pragma Elaborate (Unit)*
- Pragma ``Elaborate`` can be placed in the context clauses of a unit, after a
+ You can place pragma ``Elaborate`` in the context clauses of a unit, after a
|with| clause. It guarantees that both the spec and body of its argument will
be elaborated prior to the unit with the pragma. Note that other unrelated
units may be elaborated in between the spec and the body.
@@ -473,11 +475,12 @@ depend on.
* *pragma Elaborate_All (Unit)*
- Pragma ``Elaborate_All`` is placed in the context clauses of a unit, after
- a |with| clause. It guarantees that both the spec and body of its argument
- will be elaborated prior to the unit with the pragma, as well as all units
- |withed| by the spec and body of the argument, recursively. Note that other
- unrelated units may be elaborated in between the spec and the body.
+ You can place pragma ``Elaborate_All`` in the context clauses of a
+ unit, after a |with| clause. It guarantees that both the spec and
+ body of its argument will be elaborated prior to the unit with the
+ pragma as well as all units |withed| by the spec and body of the
+ argument, recursively. Note that other unrelated units may be
+ elaborated in between the spec and the body.
.. code-block:: ada
@@ -566,12 +569,12 @@ the server unit requires a body and does not have pragma Pure, Preelaborate,
or Elaborate_Body, then the client unit should have pragma Elaborate or
Elaborate_All for the server unit.*
-If the rule outlined above is not followed, then a program may fall in one of
-the following states:
+If you do not follow the rule outlined above, a program may fall in one of
+the following ways:
* *No elaboration order exists*
- In this case a compiler must diagnose the situation, and refuse to build an
+ In this case a compiler must diagnose the situation and refuse to build an
executable program.
* *One or more incorrect elaboration orders exist*
@@ -581,17 +584,17 @@ the following states:
* *Several elaboration orders exist, some correct, some incorrect*
- In this case the programmer has not controlled the elaboration order. As a
- result, a compiler may or may not pick one of the correct orders, and the
+ In this case, you have not controlled the elaboration order. As a
+ result, a compiler may or may not pick one of the correct orders and the
program may or may not raise ``Program_Error`` when it is run. This is the
- worst possible state because the program may fail on another compiler, or
- even another version of the same compiler.
+ worst possible state because the program may fail on another compiler or
+ even a different version of the same compiler.
* *One or more correct orders exist*
- In this case a compiler can build an executable program, and the program is
+ In this case a compiler can build an executable program and the program is
run successfully. This state may be guaranteed by following the outlined
- rules, or may be the result of good program architecture.
+ rules or may be the result of good program architecture.
Note that one additional advantage of using ``Elaborate`` and ``Elaborate_All``
is that the program continues to stay in the last state (one or more correct
@@ -602,9 +605,9 @@ orders exist) even if maintenance changes the bodies of targets.
Controlling the Elaboration Order in GNAT
=========================================
-In addition to Ada semantics and rules synthesized from them, GNAT offers
-three elaboration models to aid the programmer with specifying the correct
-elaboration order and to diagnose elaboration problems.
+In addition to Ada semantics and rules synthesized from them, GNAT
+offers three elaboration models to aid you in specifying the correct
+elaboration order and in diagnosing elaboration problems.
.. index:: Dynamic elaboration model
@@ -631,7 +634,7 @@ elaboration order and to diagnose elaboration problems.
assumptions stated above. An order obtained using the dynamic model may fail
an ABE check at run time when GNAT ignored an invocation.
- The dynamic model is enabled with compiler switch :switch:`-gnatE`.
+ You enable the dynamic model with the compiler switch :switch:`-gnatE`.
.. index:: Static elaboration model
@@ -678,24 +681,25 @@ elaboration order and to diagnose elaboration problems.
following legacy models:
- `Legacy elaboration-checking model` available in pre-18.x versions of GNAT.
- This model is enabled with compiler switch :switch:`-gnatH`.
+ You can enable this model with compiler switch :switch:`-gnatH`.
- `Legacy elaboration-order model` available in pre-20.x versions of GNAT.
- This model is enabled with binder switch :switch:`-H`.
+ You can enable this model with binder switch :switch:`-H`.
.. index:: Relaxed elaboration mode
-The dynamic, legacy, and static models can be relaxed using compiler switch
-:switch:`-gnatJ`, making them more permissive. Note that in this mode, GNAT
-may not diagnose certain elaboration issues or install run-time checks.
+You can relax the dynamic, legacy, and static models by specifying
+compiler switch :switch:`-gnatJ`, which makes them more permissive. Note
+that in this mode, GNAT may not diagnose certain elaboration issues or
+install run-time checks.
.. _Mixing_Elaboration_Models:
Mixing Elaboration Models
=========================
-It is possible to mix units compiled with a different elaboration model,
-however the following rules must be observed:
+You can mix units compiled with different elaboration models. However
+you must observe the following rules:
* A client unit compiled with the dynamic model can only |with| a server unit
that meets at least one of the following criteria:
@@ -718,7 +722,7 @@ violated, the binder emits a warning:
warning: "x.ads" has dynamic elaboration checks and with's
warning: "y.ads" which has static elaboration checks
-The warnings can be suppressed by binder switch :switch:`-ws`.
+You can suppress these warnings by specifying binder switch :switch:`-ws`.
.. _ABE_Diagnostics:
@@ -729,14 +733,14 @@ GNAT performs extensive diagnostics on a unit-by-unit basis for all scenarios
that invoke internal targets, regardless of whether the dynamic, SPARK, or
static model is in effect.
-Note that GNAT emits warnings rather than hard errors whenever it encounters an
+Note that GNAT emits warnings rather than errors whenever it encounters an
elaboration problem. This is because the elaboration model in effect may be too
-conservative, or a particular scenario may not be invoked due conditional
-execution. The warnings can be suppressed selectively with ``pragma Warnings
+conservative or a particular scenario may not be invoked due to conditional
+execution. You can selectively suppress the warnings with ``pragma Warnings
(Off)`` or globally with compiler switch :switch:`-gnatwL`.
A *guaranteed ABE* arises when the body of a target is not elaborated early
-enough, and causes *all* scenarios that directly invoke the target to fail.
+enough and causes *all* scenarios that directly invoke the target to fail.
.. code-block:: ada
@@ -763,7 +767,7 @@ the declaration of ``Val``. This invokes function ``ABE``, however the body of
>>> warning: Program_Error will be raised at run time
A *conditional ABE* arises when the body of a target is not elaborated early
-enough, and causes *some* scenarios that directly invoke the target to fail.
+enough and causes *some* scenarios that directly invoke the target to fail.
.. code-block:: ada
@@ -821,8 +825,8 @@ SPARK Diagnostics
=================
GNAT enforces the SPARK rules of elaboration as defined in the SPARK Reference
-Manual section 7.7 when compiler switch :switch:`-gnatd.v` is in effect. Note
-that GNAT emits hard errors whenever it encounters a violation of the SPARK
+Manual section 7.7 when you specify compiler switch :switch:`-gnatd.v`. Note
+that GNAT emits errors whenever it encounters a violation of the SPARK
rules.
::
@@ -938,7 +942,7 @@ subprograms, where the program controls the order of initialization explicitly.
Although this is the most desirable option, it may be impractical and involve
too much modification, especially in the case of complex legacy code.
-When faced with an elaboration circularity, the programmer should also consider
+When faced with an elaboration circularity, you should also consider
the tactics given in the suggestions section of the circularity diagnostic.
Depending on the units involved in the circularity, their |with| clauses,
purity, preelaborability, presence of elaboration-control pragmas and
@@ -951,10 +955,9 @@ following tactics to eliminate the circularity:
remove pragma Elaborate for unit "..." in unit "..."
- This tactic is suggested when the binder has determined that pragma
- ``Elaborate``:
+ The binder suggests this tactic when it has determined that:
- - Prevents a set of units from being elaborated.
+ - pragma ``Elaborate`` prevents a set of units from being elaborated.
- The removal of the pragma will not eliminate the semantic effects of the
pragma. In other words, the argument of the pragma will still be elaborated
@@ -962,7 +965,7 @@ following tactics to eliminate the circularity:
- The removal of the pragma will enable the successful ordering of the units.
- The programmer should remove the pragma as advised, and rebuild the program.
+ You should remove the pragma as advised and rebuild the program.
* Pragma Elaborate_All elimination
@@ -970,10 +973,10 @@ following tactics to eliminate the circularity:
remove pragma Elaborate_All for unit "..." in unit "..."
- This tactic is suggested when the binder has determined that pragma
- ``Elaborate_All``:
+ The binder suggests this tactic when it has determined that:
- - Prevents a set of units from being elaborated.
+ - pragma ``Elaborate_All`` prevents a set of units from being
+ elaborated.
- The removal of the pragma will not eliminate the semantic effects of the
pragma. In other words, the argument of the pragma along with its |with|
@@ -981,7 +984,7 @@ following tactics to eliminate the circularity:
- The removal of the pragma will enable the successful ordering of the units.
- The programmer should remove the pragma as advised, and rebuild the program.
+ You should remove the pragma as advised and rebuild the program.
* Pragma Elaborate_All downgrade
@@ -989,12 +992,12 @@ following tactics to eliminate the circularity:
change pragma Elaborate_All for unit "..." to Elaborate in unit "..."
- This tactic is always suggested with the pragma ``Elaborate_All`` elimination
- tactic. It offers a different alternative of guaranteeing that the argument
- of the pragma will still be elaborated prior to the unit containing the
- pragma.
+ The binder always suggests this tactic when it suggests the pragma
+ ``Elaborate_All`` elimination tactic. It offers a different
+ alternative of guaranteeing that the argument of the pragma will
+ still be elaborated prior to the unit containing the pragma.
- The programmer should update the pragma as advised, and rebuild the program.
+ You should update the pragma as advised and rebuild the program.
* Pragma Elaborate_Body elimination
@@ -1002,10 +1005,9 @@ following tactics to eliminate the circularity:
remove pragma Elaborate_Body in unit "..."
- This tactic is suggested when the binder has determined that pragma
- ``Elaborate_Body``:
+ The binder suggests this tactic when it has determined that:
- - Prevents a set of units from being elaborated.
+ - pragma ``Elaborate_Body`` prevents a set of units from being elaborated.
- The removal of the pragma will enable the successful ordering of the units.
@@ -1013,7 +1015,8 @@ following tactics to eliminate the circularity:
other purposes, such as guaranteeing the initialization of a variable
declared in the spec by elaboration code in the body.
- The programmer should remove the pragma as advised, and rebuild the program.
+ If the pragma is not required for another purpose, you should remove
+ the pragma as advised and rebuild the program.
* Use of pragma Restrictions
@@ -1021,7 +1024,7 @@ following tactics to eliminate the circularity:
use pragma Restrictions (No_Entry_Calls_In_Elaboration_Code)
- This tactic is suggested when the binder has determined that a task
+ The binder suggests this tactic when it has determined that a task
activation at elaboration time:
- Prevents a set of units from being elaborated.
@@ -1046,16 +1049,16 @@ following tactics to eliminate the circularity:
- The use of the dynamic model will enable the successful ordering of the
units.
- The programmer has two options:
+ You have two options:
- Determine the units involved in the invocation using the detailed
- invocation information, and add compiler switch :switch:`-gnatE` to the
- compilation arguments of selected files only. This approach will yield
+ invocation information and add compiler switch :switch:`-gnatE` to the
+ compilation arguments of those units only. This approach will yield
safer elaboration orders compared to the other option because it will
minimize the opportunities presented to the dynamic model for ignoring
invocations.
- - Add compiler switch :switch:`-gnatE` to the general compilation arguments.
+ - Add compiler switch :switch:`-gnatE` to the global compilation arguments.
* Use of detailed invocation information
@@ -1063,13 +1066,13 @@ following tactics to eliminate the circularity:
use detailed invocation information (compiler switch -gnatd_F)
- This tactic is always suggested with the use of the dynamic model tactic. It
- causes the circularity section of the circularity diagnostic to describe the
- flow of elaboration code from a unit to a unit, enumerating all such paths in
- the process.
+ The binder always suggests this tactic when it suggests use of the
+ dynamic model tactic. It causes the circularity section of the
+ circularity diagnostic to describe the flow of elaboration code from
+ a unit to a unit, enumerating all such paths in the process.
- The programmer should analyze this information to determine which units
- should be compiled with the dynamic model.
+ You should analyze this information to determine which units should
+ be compiled with the dynamic model.
* Forced-dependency elimination
@@ -1077,16 +1080,16 @@ following tactics to eliminate the circularity:
remove the dependency of unit "..." on unit "..." from the argument of switch -f
- This tactic is suggested when the binder has determined that a dependency
- present in the forced-elaboration-order file indicated by binder switch
- :switch:`-f`:
+ The binder suggests this tactic when it has determined that a
+ dependency present in the forced-elaboration-order file indicated by
+ binder switch :switch:`-f`:
- Prevents a set of units from being elaborated.
- The removal of the dependency will enable the successful ordering of the
units.
- The programmer should edit the forced-elaboration-order file, remove the
+ You should edit the forced-elaboration-order file, remove the
dependency, and rebind the program.
* All forced-dependency elimination
@@ -1095,11 +1098,11 @@ following tactics to eliminate the circularity:
remove switch -f
- This tactic is suggested in case editing the forced-elaboration-order file is
- not an option.
+ The binder suggests this tactic when editing the
+ forced-elaboration-order file is not an option.
- The programmer should remove binder switch :switch:`-f` from the binder
- arguments, and rebind.
+ You should remove binder switch :switch:`-f` from the binder
+ arguments and rebind.
* Multiple-circularities diagnostic
@@ -1107,16 +1110,16 @@ following tactics to eliminate the circularity:
diagnose all circularities (binder switch -d_C)
- By default, the binder will diagnose only the highest-precedence circularity.
- If the program contains multiple circularities, the binder will suggest the
- use of binder switch :switch:`-d_C` in order to obtain the diagnostics of all
- circularities.
+ By default, the binder only diagnoses the highest-precedence
+ circularity. If the program contains multiple circularities, the
+ binder will suggest the use of binder switch :switch:`-d_C` in order
+ to obtain the diagnostics for each circularity.
- The programmer should add binder switch :switch:`-d_C` to the binder
- arguments, and rebind.
+ You should add binder switch :switch:`-d_C` to the binder arguments
+ and rebind.
If none of the tactics suggested by the binder eliminate the elaboration
-circularity, the programmer should consider using one of the legacy elaboration
+circularity, you should consider using one of the legacy elaboration
models, in the following order:
* Use the pre-20.x legacy elaboration-order model, with binder switch
@@ -1150,7 +1153,7 @@ the elaboration order chosen by the binder.
.. index:: -gnatel (gnat)
:switch:`-gnatel`
- Turn on info messages on generated Elaborate[_All] pragmas
+ Turn on informational messages on generated Elaborate[_All] pragmas
This switch is only applicable to the pre-20.x legacy elaboration models.
The post-20.x elaboration model no longer relies on implicitly generated
@@ -1280,23 +1283,23 @@ the elaboration order chosen by the binder.
Summary of Procedures for Elaboration Control
=============================================
-A programmer should first compile the program with the default options, using
+You should first compile the program with the default options, using
none of the binder or compiler switches. If the binder succeeds in finding an
elaboration order, then apart from possible cases involving dispatching calls
and access-to-subprogram types, the program is free of elaboration errors.
-If it is important for the program to be portable to compilers other than GNAT,
-then the programmer should use compiler switch :switch:`-gnatel` and consider
-the messages about missing or implicitly created ``Elaborate`` and
-``Elaborate_All`` pragmas.
+If it is important for the program to be portable to compilers other
+than GNAT, you should use compiler switch :switch:`-gnatel` and
+consider the messages about missing or implicitly created
+``Elaborate`` and ``Elaborate_All`` pragmas.
-If the binder reports an elaboration circularity, the programmer has several
+If the binder reports an elaboration circularity, you have several
options:
-* Ensure that elaboration warnings are enabled. This will allow the static
+* Ensure that elaboration warnings are enabled. This allows the static
model to output trace information of elaboration issues. The trace
- information could shed light on previously unforeseen dependencies, as well
- as their origins. Elaboration warnings are enabled with compiler switch
+ information could shed light on previously unforeseen dependencies as well
+ as their origins. You enable elaboration warnings with compiler switch
:switch:`-gnatwl`.
* Cosider the tactics given in the suggestions section of the circularity
@@ -7,7 +7,7 @@ Example of Binder Output File
.. index:: Binder output (example)
This Appendix displays the source code for the output file
-generated by *gnatbind* for a simple 'Hello World' program.
+generated by ``gnatbind`` for a simple 'Hello World' program.
Comments have been added for clarification purposes.
@@ -24,8 +24,7 @@ Comments have been added for clarification purposes.
-- The main program saves the parameters (argument count,
-- argument values, environment pointer) in global variables
- -- for later access by other units including
- -- Ada.Command_Line.
+ -- for later access by other units including Ada.Command_Line.
gnat_argc : Integer;
gnat_argv : System.Address;
@@ -400,8 +399,8 @@ Comments have been added for clarification purposes.
package body ada_main is
pragma Warnings (Off);
- -- These values are reference counter associated to units which have
- -- been elaborated. It is also used to avoid elaborating the
+ -- These values are reference counters associated with units that have
+ -- been elaborated. They are used to avoid elaborating the
-- same unit twice.
E72 : Short_Integer; pragma Import (Ada, E72, "system__os_lib_E");
@@ -559,8 +558,8 @@ Comments have been added for clarification purposes.
-- Now we have the elaboration calls for all units in the partition.
-- The Elab_Spec and Elab_Body attributes generate references to the
-- implicit elaboration procedures generated by the compiler for
- -- each unit that requires elaboration. Increment a counter of
- -- reference for each unit.
+ -- each unit that requires elaboration. Also increment a reference
+ -- counter for each unit.
System.Soft_Links'Elab_Spec;
System.Exception_Table'Elab_Body;
@@ -625,11 +624,10 @@ Comments have been added for clarification purposes.
end adafinal;
-- We get to the main program of the partition by using
- -- pragma Import because if we try to with the unit and
- -- call it Ada style, then not only do we waste time
- -- recompiling it, but also, we don't really know the right
- -- switches (e.g.@: identifier character set) to be used
- -- to compile it.
+ -- pragma Import because if we try to 'with' the unit and
+ -- call it in Ada style, not only do we waste time recompiling it,
+ -- but we don't know the right switches (e.g.@: identifier
+ -- character set) to be used to compile it.
procedure Ada_Main_Program;
pragma Import (Ada, Ada_Main_Program, "_ada_hello");
@@ -734,9 +732,9 @@ binder. We have added comments to more clearly indicate the function
of each part of the generated ``Ada_Main`` package.
The code is standard Ada in all respects, and can be processed by any
-tools that handle Ada. In particular, it is possible to use the debugger
+tools that handle Ada. In particular, you can use the debugger
in Ada mode to debug the generated ``Ada_Main`` package. For example,
-suppose that for reasons that you do not understand, your program is crashing
+suppose that for reasons you don't understand, your program is crashing
during elaboration of the body of ``Ada.Text_IO``. To locate this bug,
you can place a breakpoint on the call:
@@ -745,5 +743,5 @@ you can place a breakpoint on the call:
Ada.Text_Io'Elab_Body;
and trace the elaboration routine for this package to find out where
-the problem might be (more usually of course you would be debugging
+the problem might be (more usually, of course, you would be debugging
elaboration code in your own application).
@@ -22,57 +22,58 @@ For information on GNAT Studio please refer to the
System Requirements
===================
-Even though any machine can run the GNAT toolset and GNAT Studio IDE, in order
-to get the best experience, we recommend using a machine with as many cores
-as possible since all individual compilations can run in parallel.
+Even though any machine can run the GNAT toolset and GNAT Studio IDE,
+to get the best experience we recommend using a machine with as many cores
+as possible, allowing individual compilations to run in parallel.
A comfortable setup for a compiler server is a machine with 24 physical cores
or more, with at least 48 GB of memory (2 GB per core).
-For a desktop machine, a minimum of 4 cores is recommended (8 preferred),
+For a desktop machine, we recommend a minimum of 4 cores (8 is preferred),
with at least 2GB per core (so 8 to 16GB).
-In addition, for running and navigating sources in GNAT Studio smoothly, we
-recommend at least 1.5 GB plus 3 GB of RAM per 1 million source line of code.
-In other words, we recommend at least 3 GB for for 500K lines of code and
+In addition, for running and smoothly navigating sources in GNAT Studio, we
+recommend at least 1.5 GB, plus 3 GB of RAM per million source lines of code.
+So we recommend at least 3 GB for 500K lines of code and
7.5 GB for 2 million lines of code.
-Note that using local and fast drives will also make a difference in terms of
-build and link time. Network drives such as NFS, SMB, or worse, configuration
-management filesystems (such as ClearCase dynamic views) should be avoided as
-much as possible and will produce very degraded performance (typically 2 to 3
-times slower than on local fast drives). If such slow drives cannot be avoided
-for accessing the source code, then you should at least configure your project
-file so that the result of the compilation is stored on a drive local to the
-machine performing the run. This can be achieved by setting the ``Object_Dir``
-project file attribute.
+Using fast, local drives can make a significant difference in build
+and link times. You should avoid network drives such as NFS, SMB, or
+worse, configuration management filesystems (such as ClearCase dynamic
+views) as much as possible since these will produce very degraded
+performance (typically 2 to 3 times slower than on fast, local
+drives). If you cannot avoid using such slow drives for accessing
+source code, you should at least configure your project file so
+the result of the compilation is stored on a drive local to the
+machine performing the compilation. You can do this by setting the
+``Object_Dir`` project file attribute.
.. _Running_GNAT:
Running GNAT
============
-Three steps are needed to create an executable file from an Ada source
-file:
+You need to take three steps to create an executable file from an Ada
+source file:
-* The source file(s) must be compiled.
-* The file(s) must be bound using the GNAT binder.
-* All appropriate object files must be linked to produce an executable.
+* You must compile the source file(s).
+* You must bind the file(s) using the GNAT binder.
+* You must link all appropriate object files to produce an executable.
-All three steps are most commonly handled by using the ``gnatmake``
-utility program that, given the name of the main program, automatically
-performs the necessary compilation, binding and linking steps.
+You most commonly perform all three steps by using the ``gnatmake``
+utility program. You pass it the name of the main program and it automatically
+performs the necessary compilation, binding, and linking steps.
.. _Running_a_Simple_Ada_Program:
Running a Simple Ada Program
============================
-Any text editor may be used to prepare an Ada program.
-(If Emacs is used, the optional Ada mode may be helpful in laying out the
+You may use any text editor to prepare an Ada program.
+(If you use Emacs, an optional Ada mode may be helpful in laying out the
program.)
The program text is a normal text file. We will assume in our initial
example that you have used your editor to prepare the following
-standard format text file:
+standard format text file named :file:`hello.adb`:
.. code-block:: ada
@@ -83,21 +84,18 @@ standard format text file:
Put_Line ("Hello WORLD!");
end Hello;
-This file should be named :file:`hello.adb`.
With the normal default file naming conventions, GNAT requires
that each file
contain a single compilation unit whose file name is the
-unit name,
-with periods replaced by hyphens; the
+unit name with periods replaced by hyphens; the
extension is :file:`ads` for a
spec and :file:`adb` for a body.
You can override this default file naming convention by use of the
-special pragma ``Source_File_Name`` (for further information please
-see :ref:`Using_Other_File_Names`).
+special pragma ``Source_File_Name`` (see :ref:`Using_Other_File_Names`).
Alternatively, if you want to rename your files according to this default
convention, which is probably more convenient if you will be using GNAT
-for all your compilations, then the ``gnatchop`` utility
-can be used to generate correctly-named source files
+for all your compilations, then you use can use the ``gnatchop`` utility
+to generate correctly-named source files
(see :ref:`Renaming_Files_with_gnatchop`).
You can compile the program using the following command (``$`` is used
@@ -108,16 +106,16 @@ as the command prompt in the examples in this document):
$ gcc -c hello.adb
-``gcc`` is the command used to run the compiler. This compiler is
+``gcc`` is the command used to run the compiler. It is
capable of compiling programs in several languages, including Ada and
-C. It assumes that you have given it an Ada program if the file extension is
-either :file:`.ads` or :file:`.adb`, and it will then call
+C. It assumes you have given it an Ada program if the file extension is
+either :file:`.ads` or :file:`.adb`, in which case it will call
the GNAT compiler to compile the specified file.
The :switch:`-c` switch is required. It tells ``gcc`` to only do a
compilation. (For C programs, ``gcc`` can also do linking, but this
-capability is not used directly for Ada programs, so the :switch:`-c`
-switch must always be present.)
+capability is not used directly for Ada programs, so you must always
+specify the :switch:`-c`.)
This compile command generates a file
:file:`hello.o`, which is the object
@@ -126,11 +124,11 @@ an 'Ada Library Information' file :file:`hello.ali`,
which contains additional information used to check
that an Ada program is consistent.
-To build an executable file, use either ``gnatmake`` or gprbuild with
-the name of the main file: these tools are builders that will take care of
+To build an executable file, use either ``gnatmake`` or ``gprbuild`` with
+the name of the main file: these tools are builders that perform
all the necessary build steps in the correct order.
In particular, these builders automatically recompile any sources that have
-been modified since they were last compiled, or sources that depend
+been modified since they were last compiled, as well as sources that depend
on such modified sources, so that 'version skew' is avoided.
.. index:: Version skew (avoided by ``gnatmake``)
@@ -139,7 +137,7 @@ on such modified sources, so that 'version skew' is avoided.
$ gnatmake hello.adb
-The result is an executable program called :file:`hello`, which can be
+The result is an executable program called :file:`hello`, which you can
run by entering:
.. code-block:: sh
@@ -160,8 +158,8 @@ appear in response to this command.
Running a Program with Multiple Units
=====================================
-Consider a slightly more complicated example that has three files: a
-main program, and the spec and body of a package:
+Consider a slightly more complicated example with three files: a
+main program and the spec and body of a package:
.. code-block:: ada
@@ -210,15 +208,15 @@ following three separate files:
Note that there is no required order of compilation when using GNAT.
In particular it is perfectly fine to compile the main program first.
Also, it is not necessary to compile package specs in the case where
-there is an accompanying body; you only need to compile the body. If you want
+there is an accompanying body; you only need compile the body. If you want
to submit these files to the compiler for semantic checking and not code
-generation, then use the :switch:`-gnatc` switch:
+generation, use the :switch:`-gnatc` switch:
.. code-block:: sh
$ gcc -c greetings.ads -gnatc
-Although the compilation can be done in separate steps, in practice it is
+Although you can do the compilation in separate steps, in practice it's
almost always more convenient to use the ``gnatmake`` or ``gprbuild`` tools:
.. code-block:: sh
@@ -33,16 +33,16 @@ Running and Debugging Ada Programs
This section discusses how to debug Ada programs.
-An incorrect Ada program may be handled in three ways by the GNAT compiler:
+The GNAT compiler handles an incorrect Ada program in three ways:
* The illegality may be a violation of the static semantics of Ada. In
- that case GNAT diagnoses the constructs in the program that are illegal.
- It is then a straightforward matter for the user to modify those parts of
+ that case, GNAT diagnoses the constructs in the program that are illegal.
+ It's then a straightforward matter for you to modify those parts of
the program.
* The illegality may be a violation of the dynamic semantics of Ada. In
that case the program compiles and executes, but may generate incorrect
- results, or may terminate abnormally with some exception.
+ results or may terminate abnormally with some exception.
* When presented with a program that contains convoluted errors, GNAT
itself may terminate abnormally without providing full diagnostics on
@@ -58,56 +58,57 @@ The GNAT Debugger GDB
---------------------
``GDB`` is a general purpose, platform-independent debugger that
-can be used to debug mixed-language programs compiled with ``gcc``,
+you can use to debug mixed-language programs, including compiled with ``gcc``,
and in particular is capable of debugging Ada programs compiled with
GNAT. The latest versions of ``GDB`` are Ada-aware and can handle
complex Ada data structures.
See :title:`Debugging with GDB`,
for full details on the usage of ``GDB``, including a section on
-its usage on programs. This manual should be consulted for full
+its usage on programs. That manual should be consulted for full
details. The section that follows is a brief introduction to the
philosophy and use of ``GDB``.
-When GNAT programs are compiled, the compiler optionally writes debugging
+When programs are compiled, the compiler optionally writes debugging
information into the generated object file, including information on
-line numbers, and on declared types and variables. This information is
+line numbers and on declared types and variables. This information is
separate from the generated code. It makes the object files considerably
larger, but it does not add to the size of the actual executable that
-will be loaded into memory, and has no impact on run-time performance. The
+is loaded into memory and has no impact on run-time performance. The
generation of debug information is triggered by the use of the
:switch:`-g` switch in the ``gcc`` or ``gnatmake`` command
-used to carry out the compilations. It is important to emphasize that
-the use of these options does not change the generated code.
+you used to perform the compilations. It is important to emphasize that
+it's a goal of GCC, and hence GNAT, that the use of this switch does
+not change the generated code.
-The debugging information is written in standard system formats that
+The compiler writes the debugging information in standard system formats that
are used by many tools, including debuggers and profilers. The format
of the information is typically designed to describe C types and
semantics, but GNAT implements a translation scheme which allows full
details about Ada types and variables to be encoded into these
standard C formats. Details of this encoding scheme may be found in
-the file exp_dbug.ads in the GNAT source distribution. However, the
-details of this encoding are, in general, of no interest to a user,
+the file :file:`exp_dbug.ads` in the GNAT source distribution. However, the
+details of this encoding are, in most cases, of no interest to a user,
since ``GDB`` automatically performs the necessary decoding.
When a program is bound and linked, the debugging information is
-collected from the object files, and stored in the executable image of
+collected from the object files and stored in the executable image of
the program. Again, this process significantly increases the size of
-the generated executable file, but it does not increase the size of
-the executable program itself. Furthermore, if this program is run in
+the generated executable file, but does not increase the size of
+the executable program in memory. Furthermore, if this program is run in
the normal manner, it runs exactly as if the debug information were
-not present, and takes no more actual memory.
+not present and takes no more actual memory.
However, if the program is run under control of ``GDB``, the
debugger is activated. The image of the program is loaded, at which
-point it is ready to run. If a run command is given, then the program
-will run exactly as it would have if ``GDB`` were not present. This
-is a crucial part of the ``GDB`` design philosophy. ``GDB`` is
+point it is ready to run. If you give a run command, the program
+runs exactly as it would have if ``GDB`` were not present. This
+is a crucial part of the ``GDB`` design philosophy: ``GDB`` is
entirely non-intrusive until a breakpoint is encountered. If no
-breakpoint is ever hit, the program will run exactly as it would if no
+breakpoint is ever hit, the program runs exactly as it would if no
debugger were present. When a breakpoint is hit, ``GDB`` accesses
the debugging information and can respond to user commands to inspect
-variables, and more generally to report on the state of execution.
+variables and more generally to report on the state of execution.
.. _Running_GDB:
@@ -116,9 +117,9 @@ Running GDB
This section describes how to initiate the debugger.
-The debugger can be launched from a ``GNAT Studio`` menu or
+You can launch the debugger from a ``GNAT Studio`` menu or
directly from the command line. The description below covers the latter use.
-All the commands shown can be used in the ``GNAT Studio`` debug console window,
+You can use all the commands shown in the ``GNAT Studio`` debug console window,
but there are usually more GUI-based ways to achieve the same effect.
The command to run ``GDB`` is
@@ -131,7 +132,7 @@ where ``program`` is the name of the executable file. This
activates the debugger and results in a prompt for debugger commands.
The simplest command is simply ``run``, which causes the program to run
exactly as if the debugger were not present. The following section
-describes some of the additional commands that can be given to ``GDB``.
+describes some of the additional commands that you can give to ``GDB``.
.. _Introduction_to_GDB_Commands:
@@ -144,17 +145,17 @@ See :title:`Debugging with GDB` for extensive documentation on the use
of these commands, together with examples of their use. Furthermore,
the command *help* invoked from within GDB activates a simple help
facility which summarizes the available commands and their options.
-In this section we summarize a few of the most commonly
+In this section, we summarize a few of the most commonly
used commands to give an idea of what ``GDB`` is about. You should create
a simple program with debugging information and experiment with the use of
-these ``GDB`` commands on the program as you read through the
+these ``GDB`` commands on that program as you read through the
following section.
* :samp:`set args {arguments}`
- The *arguments* list above is a list of arguments to be passed to
- the program on a subsequent run command, just as though the arguments
- had been entered on a normal invocation of the program. The ``set args``
- command is not needed if the program does not require arguments.
+ *arguments* is a list of arguments to be passed to the program on
+ a subsequent run command, just as though the arguments had been
+ entered on a normal invocation of the program. You do not need the
+ ``set args`` command if the program does not require arguments.
* :samp:`run`
@@ -162,37 +163,39 @@ following section.
the beginning. If the program is already running, that is to say if
you are currently positioned at a breakpoint, then a prompt will ask
for confirmation that you want to abandon the current execution and
- restart.
+ restart. You can also specify program arguments on this command and
+ if you specify ``run`` with no arguments, the arguments used on
+ the previous command will be used again.
* :samp:`breakpoint {location}`
- The breakpoint command sets a breakpoint, that is to say a point at which
+ This command sets a breakpoint, that is to say a point at which
execution will halt and ``GDB`` will await further
- commands. *location* is
- either a line number within a file, given in the format ``file:linenumber``,
- or it is the name of a subprogram. If you request that a breakpoint be set on
- a subprogram that is overloaded, a prompt will ask you to specify on which of
- those subprograms you want to breakpoint. You can also
- specify that all of them should be breakpointed. If the program is run
- and execution encounters the breakpoint, then the program
- stops and ``GDB`` signals that the breakpoint was encountered by
- printing the line of code before which the program is halted.
+ commands. *location* is either a line number within a file, which
+ you specify in the format ``file:linenumber``, or the name of a
+ subprogram. If you request a breakpoint be set on a subprogram
+ that is overloaded, either a prompt will ask you to specify on
+ which of those subprograms you want to breakpoint or a breakpoint
+ will be set on all of them. If the program is run and execution
+ encounters the breakpoint, the program stops and ``GDB``
+ signals that the breakpoint was encountered by printing the line
+ of code before which the program is halted.
* :samp:`catch exception {name}`
This command causes the program execution to stop whenever exception
- ``name`` is raised. If ``name`` is omitted, then the execution is
+ ``name`` is raised. If you omit ``name``, execution is
suspended when any exception is raised.
* :samp:`print {expression}`
- This will print the value of the given expression. Most simple
+ This prints the value of the given expression. Most
Ada expression formats are properly handled by ``GDB``, so the expression
can contain function calls, variables, operators, and attribute references.
* :samp:`continue`
- Continues execution following a breakpoint, until the next breakpoint or the
+ Continues execution following a breakpoint until the next breakpoint or the
termination of the program.
@@ -203,29 +206,33 @@ following section.
* :samp:`next`
- Executes a single line. If this line is a subprogram call, executes and
- returns from the call.
+ Executes a single line. If this line is a subprogram call, the
+ program executes that call and returns.
* :samp:`list`
- Lists a few lines around the current source location. In practice, it
- is usually more convenient to have a separate edit window open with the
- relevant source file displayed. Successive applications of this command
- print subsequent lines. The command can be given an argument which is a
- line number, in which case it displays a few lines around the specified one.
+
+ Lists a few lines around the current source location. In practice,
+ it is usually more convenient to have a separate edit window open
+ with the relevant source file displayed. ``emacs`` has debugging
+ modes that display both the relevant source and ``GDB`` commands
+ and output. Successive applications of this command print
+ subsequent lines. You can give this command an argument which is a
+ line number, in which case it displays a few lines around the
+ specified line.
* :samp:`backtrace`
Displays a backtrace of the call chain. This command is typically
- used after a breakpoint has occurred, to examine the sequence of calls that
+ used after a breakpoint has occurred to examine the sequence of calls that
leads to the current breakpoint. The display includes one line for each
activation record (frame) corresponding to an active subprogram.
* :samp:`up`
At a breakpoint, ``GDB`` can display the values of variables local
- to the current frame. The command ``up`` can be used to
- examine the contents of other active frames, by moving the focus up
+ to the current frame. You can use the command ``up`` to
+ examine the contents of other active frames by moving the focus up
the stack, that is to say from callee to caller, one frame at a time.
@@ -241,24 +248,26 @@ following section.
* :samp:`kill`
Kills the child process in which the program is running under GDB.
- This may be useful for several purposes:
+ You may find this useful for several purposes:
* It allows you to recompile and relink your program, since on many systems
you cannot regenerate an executable file while it is running in a process.
- * You can run your program outside the debugger, on systems that do not
+ * You can run your program outside the debugger on systems that do not
permit executing a program outside GDB while breakpoints are set
within GDB.
* It allows you to debug a core dump rather than a running process.
-The above list is a very short introduction to the commands that
+The above is a very short introduction to the commands that
``GDB`` provides. Important additional capabilities, including conditional
breakpoints, the ability to execute command sequences on a breakpoint,
the ability to debug at the machine instruction level and many other
features are described in detail in :title:`Debugging with GDB`.
Note that most commands can be abbreviated
-(for example, c for continue, bt for backtrace).
+(for example, "c" for ``continue`` and "bt" for ``backtrace``) and only enough
+characters need be typed to disambiguate the command (e.g., "br" for
+``breakpoint``).
.. _Using_Ada_Expressions:
@@ -268,18 +277,18 @@ Using Ada Expressions
.. index:: Ada expressions (in gdb)
-``GDB`` supports a fairly large subset of Ada expression syntax, with some
+``GDB`` supports a very large subset of Ada expression syntax, with some
extensions. The philosophy behind the design of this subset is
- * That ``GDB`` should provide basic literals and access to operations for
+ * ``GDB`` should provide basic literals and access to operations for
arithmetic, dereferencing, field selection, indexing, and subprogram calls,
leaving more sophisticated computations to subprograms written into the
program (which therefore may be called from ``GDB``).
- * That type safety and strict adherence to Ada language restrictions
+ * Type safety and strict adherence to Ada language restrictions
are not particularly relevant in a debugging context.
- * That brevity is important to the ``GDB`` user.
+ * Brevity is important to the ``GDB`` user.
Thus, for brevity, the debugger acts as if there were
implicit ``with`` and ``use`` clauses in effect for all user-written
@@ -296,29 +305,29 @@ Calling User-Defined Subprograms
--------------------------------
An important capability of ``GDB`` is the ability to call user-defined
-subprograms while debugging. This is achieved simply by entering
+subprograms while debugging. You do this by simply entering
a subprogram call statement in the form:
::
call subprogram-name (parameters)
-The keyword ``call`` can be omitted in the normal case where the
+You can omit the keyword ``call`` in the normal case where the
``subprogram-name`` does not coincide with any of the predefined
``GDB`` commands.
The effect is to invoke the given subprogram, passing it the
-list of parameters that is supplied. The parameters can be expressions and
+list of parameters that is supplied. The parameters you specify can be expressions and
can include variables from the program being debugged. The
subprogram must be defined
-at the library level within your program, and ``GDB`` will call the
+at the library level within your program and ``GDB`` will call the
subprogram within the environment of your program execution (which
means that the subprogram is free to access or even modify variables
within your program).
-The most important use of this facility is in allowing the inclusion of
+The most important use of this facility that you can include
debugging routines that are tailored to particular data structures
-in your program. Such debugging routines can be written to provide a suitably
+in your program. You can write such debugging routines to provide a suitably
high-level description of an abstract type, rather than a low-level dump
of its physical layout. After all, the standard
``GDB print`` command only knows the physical layout of your
@@ -330,21 +339,21 @@ the contents of the tree nodes used to represent the program internally.
But tree nodes are represented simply by an integer value (which in turn
is an index into a table of nodes).
Using the ``print`` command on a tree node would simply print this integer
-value, which is not very useful. But the PN routine (defined in file
-treepr.adb in the GNAT sources) takes a tree node as input, and displays
+value, which is not very useful. But the ``PN`` routine (defined in file
+:file:`treepr.adb` in the GNAT sources) takes a tree node as input and displays
a useful high level representation of the tree node, which includes the
-syntactic category of the node, its position in the source, the integers
-that denote descendant nodes and parent node, as well as varied
+syntactic category of the node, its position in the source,
+the descendant nodes and parent node, as well as lots of
semantic information. To study this example in more detail, you might want to
-look at the body of the PN procedure in the stated file.
+look at the body of the ``PN`` procedure in the above file.
-Another useful application of this capability is to deal with situations of
+Another useful application of this capability is to deal with situations where
complex data which are not handled suitably by GDB. For example, if you specify
Convention Fortran for a multi-dimensional array, GDB does not know that
the ordering of array elements has been switched and will not properly
address the array elements. In such a case, instead of trying to print the
elements directly from GDB, you can write a callable procedure that prints
-the elements in the desired format.
+the elements in the format you desire.
.. _Using_the_Next_Command_in_a_Function:
@@ -358,7 +367,7 @@ arises in the case of a ``return`` statement.
Part of the code for a return statement is the 'epilogue' of the function.
This is the code that returns to the caller. There is only one copy of
-this epilogue code, and it is typically associated with the last return
+this epilogue code and it is typically associated with the last return
statement in the function if there is more than one return. In some
implementations, this epilogue is associated with the first statement
of the function.
@@ -426,8 +435,8 @@ Ada Tasks
* 4 80ae800 3 80b8000 15 Running c
- In this listing, the asterisk before the first task indicates it to be the
- currently running task. The first column lists the task ID that is used
+ In this listing, the asterisk before the first task indicates it's
+ currently running task. The first column lists the task ID used
to refer to tasks in the following commands.
@@ -439,12 +448,12 @@ Ada Tasks
*linespec* specifies source lines.
Use the qualifier :samp:`task {taskid}` with a breakpoint command
- to specify that you only want ``GDB`` to stop the program when a
+ to specify that you only want ``GDB`` to stop the program when that
particular Ada task reaches this breakpoint. *taskid* is one of the
numeric task identifiers assigned by ``GDB``, shown in the first
column of the ``info tasks`` display.
- If you do not specify :samp:`task {taskid}` when you set a
+ If you don't specify :samp:`task {taskid}` when you set a
breakpoint, the breakpoint applies to *all* tasks of your
program.
@@ -457,12 +466,12 @@ Ada Tasks
* :samp:`task {taskno}`
This command allows switching to the task referred by *taskno*. In
- particular, this allows browsing of the backtrace of the specified
- task. It is advisable to switch back to the original task before
- continuing execution otherwise the scheduling of the program may be
- perturbed.
+ particular, it allows browsing the backtrace of the specified
+ task. You should switch back to the original task before
+ continuing execution; otherwise the scheduling of the program may be
+ disturbed.
-For more detailed information on the tasking support,
+For more detailed information on tasking support,
see :title:`Debugging with GDB`.
@@ -474,13 +483,14 @@ see :title:`Debugging with GDB`.
Debugging Generic Units
-----------------------
-GNAT always uses code expansion for generic instantiation. This means that
-each time an instantiation occurs, a complete copy of the original code is
-made, with appropriate substitutions of formals by actuals.
+GNAT always uses the code expansion mechanism for generic
+instantiation. This means that each time an instantiation occurs, the
+compiler makes a complete copy of the original code, with
+appropriate substitutions of formals by actuals.
-It is not possible to refer to the original generic entities in
-``GDB``, but it is always possible to debug a particular instance of
-a generic, by using the appropriate expanded names. For example, if we have
+You can't refer to the original generic entities in ``GDB``, but you
+can debug a particular instance of a generic by using the appropriate
+expanded names. For example, if we have
.. code-block:: ada
@@ -517,8 +527,8 @@ use the command:
(gdb) break g.k2.kp
When the breakpoint occurs, you can step through the code of the
-instance in the normal manner and examine the values of local variables, as for
-other units.
+instance in the normal manner and examine the values of local
+variables, as you do for other units.
.. index:: Remote Debugging with gdbserver
@@ -528,17 +538,17 @@ other units.
Remote Debugging with gdbserver
-------------------------------
-On platforms where gdbserver is supported, it is possible to use this tool
+On platforms that support ``gdbserver``, you can use this tool
to debug your application remotely. This can be useful in situations
where the program needs to be run on a target host that is different
from the host used for development, particularly when the target has
a limited amount of resources (either CPU and/or memory).
-To do so, start your program using gdbserver on the target machine.
-gdbserver then automatically suspends the execution of your program
-at its entry point, waiting for a debugger to connect to it. The
-following commands starts an application and tells gdbserver to
-wait for a connection with the debugger on localhost port 4444.
+To do so, start your program using ``gdbserver`` on the target machine.
+``gdbserver`` automatically suspends the execution of your program
+at its entry point, waiting for a debugger to connect to it. You use the
+following commands to start an application and tell ``gdbserver`` to
+wait for a connection with the debugger on ``localhost`` port 4444.
::
@@ -547,10 +557,10 @@ wait for a connection with the debugger on localhost port 4444.
Process program created; pid = 5685
Listening on port 4444
-Once gdbserver has started listening, we can tell the debugger to establish
-a connection with this gdbserver, and then start the same debugging session
-as if the program was being debugged on the same host, directly under
-the control of GDB.
+Once ``gdbserver`` has started listening, you can tell the debugger to
+establish a connection with this ``gdbserver``, and then start a
+debugging session as if the program was being debugged on the
+same host, directly under the control of ``GDB``.
::
@@ -566,13 +576,14 @@ the control of GDB.
Breakpoint 1, foo () at foo.adb:4
4 end foo;
-It is also possible to use gdbserver to attach to an already running
-program, in which case the execution of that program is simply suspended
-until the connection between the debugger and gdbserver is established.
+You can also use ``gdbserver`` to attach to an already running
+program, in which case the execution of that program is suspended
+until you have established the connection between the debugger and ``gdbserver``.
-For more information on how to use gdbserver, see the *Using the gdbserver Program*
-section in :title:`Debugging with GDB`.
-GNAT provides support for gdbserver on x86-linux, x86-windows and x86_64-linux.
+For more information on how to use ``gdbserver``, see the *Using the
+gdbserver Program* section in :title:`Debugging with GDB`. GNAT
+provides support for ``gdbserver`` on x86-linux, x86-windows and
+x86_64-linux.
.. index:: Abnormal Termination or Failure to Terminate
@@ -584,7 +595,7 @@ GNAT Abnormal Termination or Failure to Terminate
When presented with programs that contain serious errors in syntax
or semantics,
-GNAT may on rare occasions experience problems in operation, such
+GNAT may, on rare occasions, experience problems such
as aborting with a
segmentation fault or illegal memory access, raising an internal
exception, terminating abnormally, or failing to terminate at all.
@@ -592,13 +603,13 @@ In such cases, you can activate
various features of GNAT that can help you pinpoint the construct in your
program that is the likely source of the problem.
-The following strategies are presented in increasing order of
-difficulty, corresponding to your experience in using GNAT and your
-familiarity with compiler internals.
+The following strategies for you to use in such cases are presented in
+increasing order of difficulty, corresponding to your experience in
+using GNAT and your familiarity with compiler internals.
-* Run ``gcc`` with the :switch:`-gnatf`. This first
- switch causes all errors on a given line to be reported. In its absence,
- only the first error on a line is displayed.
+* Run ``gcc`` with the :switch:`-gnatf`. This switch causes all errors
+ on a given line to be reported. In its absence, GNAT only displays
+ the first error on a line.
The :switch:`-gnatdO` switch causes errors to be displayed as soon as they
are encountered, rather than after compilation is terminated. If GNAT
@@ -609,7 +620,7 @@ familiarity with compiler internals.
mode, ``gcc`` produces ongoing information about the progress of the
compilation and provides the name of each procedure as code is
generated. This switch allows you to find which Ada procedure was being
- compiled when it encountered a code generation problem.
+ compiled when it encountered a problem.
.. index:: -gnatdc switch
@@ -620,7 +631,7 @@ familiarity with compiler internals.
* Finally, you can start
``gdb`` directly on the ``gnat1`` executable. ``gnat1`` is the
- front-end of GNAT, and can be run independently (normally it is just
+ front-end of GNAT and can be run independently (normally it is just
called from ``gcc``). You can use ``gdb`` on ``gnat1`` as you
would on a C program (but :ref:`The_GNAT_Debugger_GDB` for caveats). The
``where`` command is the first line of attack; the variable
@@ -635,7 +646,7 @@ familiarity with compiler internals.
Naming Conventions for GNAT Source Files
----------------------------------------
-In order to examine the workings of the GNAT system, the following
+In order to bettter understand the workings of the GNAT system, the following
brief description of its organization may be helpful:
* Files with prefix :file:`sc` contain the lexical scanner.
@@ -646,14 +657,18 @@ brief description of its organization may be helpful:
* All files prefixed with :file:`sem` perform semantic analysis. The
numbers correspond to chapters of the Ada standard. For example, all
- issues involving context clauses can be found in :file:`sem_ch10.adb`. In
- addition, some features of the language require sufficient special processing
- to justify their own semantic files: sem_aggr for aggregates, sem_disp for
- dynamic dispatching, etc.
+ issues involving context clauses can be found in
+ :file:`sem_ch10.adb`. In addition, some features of the language
+ require sufficient special processing to justify their own semantic
+ files, such as :file:`sem_aggr.adb` for aggregates and
+ :file:`sem_disp.adb` for dynamic dispatching.
* All files prefixed with :file:`exp` perform normalization and
expansion of the intermediate representation (abstract syntax tree, or AST).
- these files use the same numbering scheme as the parser and semantics files.
+ The expansion has the effect of lowering the semantic level of the AST to
+ a level closer to what the backend can handle. For example, it converts
+ tasking operations into calls to the appropriate runtime routines.
+ These files use the same numbering scheme as the parser and semantics files.
For example, the construction of record initialization procedures is done in
:file:`exp_ch3.adb`.
@@ -670,6 +685,10 @@ brief description of its organization may be helpful:
* The files :file:`einfo.ads` and :file:`einfo.adb` detail the attributes of
all entities, computed during semantic analysis.
+* The files prefixed with :file:`gen_il` generate most of the functions
+ defined in :file:`sinfo.ads` and :file:`einfo.ads`, which set and get
+ various fields and flags of the AST.
+
* Library management issues are dealt with in files with prefix
:file:`lib`.
@@ -701,7 +720,7 @@ Getting Internal Debugging Information
--------------------------------------
Most compilers have internal debugging switches and modes. GNAT
-does also, except GNAT internal debugging switches and modes are not
+does too, except GNAT internal debugging switches and modes are not
secret. A summary and full description of all the compiler and binder
debug flags are in the file :file:`debug.adb`. You must obtain the
sources of the compiler to see the full detailed effects of these flags.
@@ -709,11 +728,11 @@ sources of the compiler to see the full detailed effects of these flags.
The switches that print the source of the program (reconstructed from
the internal tree) are of general interest for user programs, as are the
options to print
-the full internal tree, and the entity table (the symbol table
+the full internal tree and the entity table (the symbol table
information). The reconstructed source provides a readable version of the
-program after the front-end has completed analysis and expansion,
+program after the front-end has completed analysis and expansion
and is useful when studying the performance of specific constructs.
-For example, constraint checks are indicated, complex aggregates
+For example, constraint checks are shown explicitly, complex aggregates
are replaced with loops and assignments, and tasking primitives
are replaced with run-time calls.
@@ -740,7 +759,7 @@ that is to say the subprogram currently executing the instruction
from which we want to obtain the traceback.
Note that there is no runtime performance penalty when stack traceback
-is enabled, and no exception is raised during program execution.
+is enabled and no exception is raised during program execution.
.. index:: traceback, non-symbolic
@@ -755,15 +774,16 @@ for a complete list of supported platforms.
.. rubric:: Tracebacks From an Unhandled Exception
-A runtime non-symbolic traceback is a list of addresses of call instructions.
-To enable this feature you must use the :switch:`-E` ``gnatbind`` option. With
-this option a stack traceback is stored as part of exception information.
+A runtime non-symbolic traceback is a list of addresses of call
+instructions. To enable this feature you must use the :switch:`-E`
+``gnatbind`` switch. With this switch, a stack traceback is stored at
+runtime as part of exception information.
You can translate this information using the ``addr2line`` tool, provided that
the program is compiled with debugging options (see :ref:`Switches_for_gcc`)
and linked at a fixed position with :switch:`-no-pie`.
-Here is a simple example with ``gnatmake``:
+Here's a simple example with ``gnatmake``:
.. code-block:: ada
@@ -794,11 +814,11 @@ Here is a simple example with ``gnatmake``:
Call stack traceback locations:
0x401373 0x40138b 0x40139c 0x401335 0x4011c4 0x4011f1 0x77e892a4
-As we see the traceback lists a sequence of addresses for the unhandled
-exception ``CONSTRAINT_ERROR`` raised in procedure P1. It is easy to
-guess that this exception come from procedure P1. To translate these
-addresses into the source lines where the calls appear, the ``addr2line``
-tool needs to be invoked like this:
+As we can see, the traceback lists a sequence of addresses for the unhandled
+exception ``CONSTRAINT_ERROR`` raised in procedure P1. It's easy to
+see that this exception come from procedure P1. To translate these
+addresses into the source lines where the calls appear, you need to
+invoke the ``addr2line`` tool like this:
::
@@ -836,13 +856,13 @@ The ``addr2line`` tool has several other useful options:
0x77e892a4: ?? ??:0
-From this traceback we can see that the exception was raised in :file:`stb.adb`
+From this traceback, we can see that the exception was raised in :file:`stb.adb`
at line 5, which was reached from a procedure call in :file:`stb.adb` at line
-10, and so on. The :file:`b~std.adb` is the binder file, which contains the
-call to the main program. :ref:`Running_gnatbind`. The remaining entries are
-assorted runtime routines and the output will vary from platform to platform.
+10, and so on. :file:`b~std.adb` is the binder file, which contains the
+call to the main program; :ref:`Running_gnatbind`. The remaining entries are
+assorted runtime routines. The output will vary from platform to platform.
-It is also possible to use ``GDB`` with these traceback addresses to debug
+You can also use ``GDB`` with these traceback addresses to debug
the program. For example, we can break at a given code location, as reported
in the stack traceback::
@@ -868,9 +888,9 @@ Executables on recent Linux and Windows versions, in other words without
using the switch :switch:`-no-pie` during linking, you need to use the
``gnatsymbolize`` tool with :switch:`--load` instead of the ``addr2line``
tool. The main difference is that you need to copy the Load Address output
-in the traceback ahead of the sequence of addresses. And the default mode
+in the traceback ahead of the sequence of addresses. The default mode
of ``gnatsymbolize`` is equivalent to that of ``addr2line`` with the above
-switches, so none of them is needed::
+switches, so none of them are needed::
$ gnatmake stb -g -bargs -E
$ stb
@@ -895,10 +915,10 @@ switches, so none of them is needed::
.. rubric:: Tracebacks From Exception Occurrences
-Non-symbolic tracebacks are obtained by using the :switch:`-E` binder argument.
-The stack traceback is attached to the exception information string, and can
-be retrieved in an exception handler within the Ada program, by means of the
-Ada facilities defined in ``Ada.Exceptions``. Here is a simple example:
+Non-symbolic tracebacks are obtained by using the :switch:`-E` binder switch.
+The stack traceback is attached to the exception information string and you can
+retrieve it in an exception handler within the Ada program by means of the
+Ada facilities defined in ``Ada.Exceptions``. Here's a simple example:
.. code-block:: ada
@@ -941,15 +961,15 @@ Ada facilities defined in ``Ada.Exceptions``. Here is a simple example:
.. rubric:: Tracebacks From Anywhere in a Program
-It is also possible to retrieve a stack traceback from anywhere in a program.
-For this you need to use the ``GNAT.Traceback`` API. This package includes a
-procedure called ``Call_Chain`` that computes a complete stack traceback, as
-well as useful display procedures described below. It is not necessary to use
-the :switch:`-E` ``gnatbind`` option in this case, because the stack traceback
+You can also retrieve a stack traceback from anywhere in a program.
+For this, you need to use the ``GNAT.Traceback`` API. This package includes a
+procedure called ``Call_Chain`` that computes a complete stack traceback as
+well as useful display procedures described below. You don't have to use
+the :switch:`-E` ``gnatbind`` switch in this case because the stack traceback
mechanism is invoked explicitly.
-In the following example we compute a traceback at a specific location in the
-program, and we display it using ``GNAT.Debug_Utilities.Image`` to convert
+In the following example, we compute a traceback at a specific location in the
+program and display it using ``GNAT.Debug_Utilities.Image`` to convert
addresses to strings:
@@ -1011,7 +1031,7 @@ addresses to strings:
0x4011F1 0x77E892A4
-You can then get further information by invoking the ``addr2line`` tool or
+You can get even more information by invoking the ``addr2line`` tool or
the ``gnatsymbolize`` tool as described earlier (note that the hexadecimal
addresses need to be specified in C format, with a leading '0x').
@@ -1030,7 +1050,7 @@ Note that this feature is not supported on all platforms. See
list of currently supported platforms.
Note that the symbolic traceback requires that the program be compiled
-with debug information. If it is not compiled with debug information
+with debug information. If you do not compile it with debug information,
only the non-symbolic information will be valid.
@@ -1083,10 +1103,10 @@ Here is an example:
.. rubric:: Tracebacks From Anywhere in a Program
-It is possible to get a symbolic stack traceback
-from anywhere in a program, just as for non-symbolic tracebacks.
+You can get a symbolic stack traceback
+from anywhere in a program, just as you can for non-symbolic tracebacks.
The first step is to obtain a non-symbolic
-traceback, and then call ``Symbolic_Traceback`` to compute the symbolic
+traceback. Then call ``Symbolic_Traceback`` to compute the symbolic
information. Here is an example:
.. code-block:: ada
@@ -1123,11 +1143,11 @@ information. Here is an example:
.. rubric:: Automatic Symbolic Tracebacks
-Symbolic tracebacks may also be enabled by using the -Es switch to gnatbind (as
-in ``gprbuild -g ... -bargs -Es``).
-This will cause the Exception_Information to contain a symbolic traceback,
-which will also be printed if an unhandled exception terminates the
-program.
+You may also enable symbolic tracebacks by using
+the :switch:`-Es` switch to gnatbind (as in ``gprbuild -g ... -bargs -Es``).
+This causes the Exception_Information to contain a symbolic
+traceback, which will also be printed if an unhandled exception
+terminates the program.
.. _Pretty-Printers_For_The_GNAT_Runtime:
@@ -1161,8 +1181,8 @@ standard container, such as ``Ada.Containers.Ordered_Maps.Map``:
end PP;
When this program is built with debugging information and run under
-GDB up to the ``Map.Clear`` statement, trying to print ``Map`` will
-yield information that is only relevant to the developers of our standard
+``GDB`` up to the ``Map.Clear`` statement, trying to print ``Map`` will
+yield information that is only relevant to the developers of the standard
containers:
::
@@ -1181,18 +1201,19 @@ containers:
)
)
-Fortunately, GDB has a feature called `pretty-printers
+Fortunately, ``GDB ``has a feature called `pretty-printers
<http://docs.adacore.com/gdb-docs/html/gdb.html#Pretty_002dPrinter-Introduction>`_,
-which allows customizing how GDB displays data structures. The GDB
-shipped with GNAT embeds such pretty-printers for the most common
-containers in the standard library. To enable them, either run the
-following command manually under GDB or add it to your ``.gdbinit`` file:
+which allows customizing how ``GDB`` displays data structures. The
+``GDB`` shipped with GNAT embeds such pretty-printers for the most
+common containers in the standard library. To enable them, either run
+the following command manually under ``GDB`` or add it to your
+:file:`.gdbinit` file:
::
python import gnatdbg; gnatdbg.setup()
-Once this is done, GDB's ``print`` command will automatically use
+Once you've done this, ``GDB``'s ``print`` command will automatically use
these pretty-printers when appropriate. Using the previous example:
::
@@ -1209,8 +1230,8 @@ including when displaying the arguments of a called subprogram (in
GDB's ``backtrace`` command) or when printing the value returned by a
function (in GDB's ``finish`` command).
-To display a value without involving pretty-printers, ``print`` can be
-invoked with its ``/r`` option:
+To display a value without involving pretty-printers, you can invoke
+``print`` with its ``/r`` option:
::
@@ -1218,7 +1239,7 @@ invoked with its ``/r`` option:
$1 = (
tree => (...
-Finer control of pretty-printers is also possible: see `GDB's online
+You can also obtain finer control of pretty-printers: see `GDB's online
documentation
<http://docs.adacore.com/gdb-docs/html/gdb.html#Pretty_002dPrinter-Commands>`_
for more information.
@@ -1243,20 +1264,21 @@ Profiling an Ada Program with gprof
-----------------------------------
This section is not meant to be an exhaustive documentation of ``gprof``.
-Full documentation for it can be found in the :title:`GNU Profiler User's Guide`
+You can find full documentation for it in the :title:`GNU Profiler User's Guide`
documentation that is part of this GNAT distribution.
Profiling a program helps determine the parts of a program that are executed
-most often, and are therefore the most time-consuming.
+most often and are therefore the most time-consuming.
``gprof`` is the standard GNU profiling tool; it has been enhanced to
better handle Ada programs and multitasking.
-It is currently supported on the following platforms
+It's currently supported on the following platforms
* Linux x86/x86_64
* Windows x86/x86_64 (without PIE support)
-In order to profile a program using ``gprof``, several steps are needed:
+In order to profile a program using ``gprof``, you need to perform the
+following steps:
#. Instrument the code, which requires a full recompilation of the project with the
proper switches.
@@ -1266,7 +1288,7 @@ In order to profile a program using ``gprof``, several steps are needed:
#. Analyze the results using the ``gprof`` tool.
-The following sections detail the different steps, and indicate how
+The following sections detail the different steps and indicate how
to interpret the results.
@@ -1278,22 +1300,22 @@ Compilation for profiling
.. index:: -pg (gcc), for profiling
.. index:: -pg (gnatlink), for profiling
-In order to profile a program the first step is to tell the compiler
-to generate the necessary profiling information. The compiler switch to be used
-is ``-pg``, which must be added to other compilation switches. This
-switch needs to be specified both during compilation and link stages, and can
-be specified once when using gnatmake:
+In order to profile a program, you must first to tell the compiler
+to generate the necessary profiling information. You do this using the compiler switch :switch:`-pg`, which you must add to other compilation switches. You need
+to specify this
+switch during compilation and link stages, and you can
+specified it only once when using ``gnatmake``:
::
$ gnatmake -f -pg -P my_project
-Note that only the objects that were compiled with the ``-pg`` switch will
-be profiled; if you need to profile your whole project, use the ``-f``
-gnatmake switch to force full recompilation.
+Note that only the objects that were compiled with the :switch:`-pg` switch will
+be profiled; if you need to profile your whole project, use the :switch:`-f`
+``gnatmake`` switch to force full recompilation.
-Note that on Windows, gprof does not support PIE. The ``-no-pie`` switch
-should be added to the linker flags to disable this feature.
+Note that on Windows, ``gprof`` does not support PIE. You should add
+the :switch:`-no-pie` switch to the linker flags to disable PIE.
.. _Program_execution:
@@ -1310,7 +1332,7 @@ properly analyzed.
Once the program completes execution, a data file called :file:`gmon.out` is
generated in the directory where the program was launched from. If this file
-already exists, it will be overwritten.
+already exists, it will be overwritten by running the program.
.. _Running_gprof:
@@ -1318,7 +1340,7 @@ already exists, it will be overwritten.
Running gprof
^^^^^^^^^^^^^
-The ``gprof`` tool is called as follow:
+You can call the ``gprof`` tool as follows:
::
@@ -1330,71 +1352,71 @@ or simply:
$ gprof my_prog
-The complete form of the gprof command line is the following:
+The complete form of the ``gprof`` command line is the following:
::
$ gprof [switches] [executable [data-file]]
-``gprof`` supports numerous switches. The order of these
-switch does not matter. The full list of options can be found in
-the GNU Profiler User's Guide documentation that comes with this documentation.
+``gprof`` supports numerous switches, whose order does not matter. You
+can find the full list of switches in the :title:`GNU Profiler
+User's Guide`.
-The following is the subset of those switches that is most relevant:
+The following are the most relevant of those switches:
.. index:: --demangle (gprof)
-:samp:`--demangle[={style}]`, :samp:`--no-demangle`
- These options control whether symbol names should be demangled when
- printing output. The default is to demangle C++ symbols. The
- ``--no-demangle`` option may be used to turn off demangling. Different
+:switch:`--demangle[={style}]`, :switch:`--no-demangle`
+ These switches control whether symbol names should be demangled when
+ printing output. The default is to demangle C++ symbols. You can use
+ :switch:`--no-demangle` to turn off demangling. Different
compilers have different mangling styles. The optional demangling style
argument can be used to choose an appropriate demangling style for your
compiler, in particular Ada symbols generated by GNAT can be demangled using
- ``--demangle=gnat``.
+ :switch:`--demangle=gnat`.
.. index:: -e (gprof)
-:samp:`-e {function_name}`
- The :samp:`-e {function}` option tells ``gprof`` not to print
- information about the function ``function_name`` (and its
- children...) in the call graph. The function will still be listed
+:switch:`-e {function_name}`
+ The :switch:`-e {function}` option tells ``gprof`` not to print
+ information about the function ``function_name`` and its
+ children in the call graph. The function will still be listed
as a child of any functions that call it, but its index number will be
- shown as ``[not printed]``. More than one ``-e`` option may be
- given; only one ``function_name`` may be indicated with each ``-e``
- option.
+ shown as ``[not printed]``. You may specify more than one :switch:`-e` switch,
+ but you may only include one ``function_name`` with each :switch:`-e`
+ switch.
.. index:: -E (gprof)
-:samp:`-E {function_name}`
- The :samp:`-E {function}` option works like the ``-e`` option, but
+:switch:`-E {function_name}`
+ The :switch:`-E {function}` switch works like the :switch:`-e` switch, but
execution time spent in the function (and children who were not called from
- anywhere else), will not be used to compute the percentages-of-time for
- the call graph. More than one :switch:`-E` option may be given; only one
- ``function_name`` may be indicated with each :switch:`-E`` option.
+ anywhere else) will not be used to compute the percentages-of-time for
+ the call graph. You may specify more than one :switch:`-E` switch, but
+ you may only include one ``function_name`` with each :switch:`-E` switch.
.. index:: -f (gprof)
-:samp:`-f {function_name}`
- The :samp:`-f {function}` option causes ``gprof`` to limit the
- call graph to the function ``function_name`` and its children (and
- their children...). More than one ``-f`` option may be given;
- only one ``function_name`` may be indicated with each ``-f``
- option.
+:switch:`-f {function_name}`
+ The :switch:`-f {function}` switch causes ``gprof`` to limit the
+ call graph to the function ``function_name`` and its children and
+ their children. You may specify more than one :switch:`-f` switch,
+ but you may only include one ``function_name`` with each :switch:`-f` switch.
.. index:: -F (gprof)
-:samp:`-F {function_name}`
- The :samp:`-F {function}` option works like the ``-f`` option, but
- only time spent in the function and its children (and their
- children...) will be used to determine total-time and
- percentages-of-time for the call graph. More than one ``-F`` option
- may be given; only one ``function_name`` may be indicated with each
- ``-F`` option. The ``-F`` option overrides the ``-E`` option.
+:switch:`-F {function_name}`
+ The :switch:`-F {function}` switch works like the :switch:`-f` switch, but
+ only time spent in the function and its children and their
+ children will be used to determine total-time and
+ percentages-of-time for the call graph. You may specify more than one
+ :switch:`-F` switch, but you may include only one ``function_name`` with each
+ :switch:`-F` switch. The :switch:`-F` switch overrides the :switch:`-E`
+ switch.
.. _Interpretation_of_profiling_results:
@@ -1402,17 +1424,17 @@ The following is the subset of those switches that is most relevant:
Interpretation of profiling results
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-The results of the profiling analysis are represented by two arrays: the
-'flat profile' and the 'call graph'. Full documentation of those outputs
-can be found in the GNU Profiler User's Guide.
+The results of the profiling analysis are represented by two arrays:
+the 'flat profile' and the 'call graph'. You can find full
+documentation of those outputs in the :title:`GNU Profiler User's Guide`.
-The flat profile shows the time spent in each function of the program, and how
-many time it has been called. This allows you to locate easily the most
+The flat profile shows the time spent in each function of the program and how
+many time it has been called. This allows you to easily locate the most
time-consuming functions.
The call graph shows, for each subprogram, the subprograms that call it,
and the subprograms that it calls. It also provides an estimate of the time
-spent in each of those callers/called subprograms.
+spent in each of those callers and called subprograms.
@@ -1424,7 +1446,7 @@ Improving Performance
.. index:: Improving performance
This section presents several topics related to program performance.
-It first describes some of the tradeoffs that need to be considered
+It first describes some of the tradeoffs that you need to consider
and some of the techniques for making your program run faster.
It then documents the unused subprogram/data elimination feature,
@@ -1436,7 +1458,7 @@ Performance Considerations
--------------------------
The GNAT system provides a number of options that allow a trade-off
-between
+between:
* performance of the generated code
@@ -1446,9 +1468,9 @@ between
* the degree of run-time checking.
-The defaults (if no options are selected) aim at improving the speed
+The default (if you don't select any switches) aims at improving the speed
of compilation and minimizing dependences, at the expense of performance
-of the generated code:
+of the generated code and consists of:
* no optimization
@@ -1457,7 +1479,7 @@ of the generated code:
* all run-time checks enabled except overflow and elaboration checks
These options are suitable for most program development purposes. This
-section describes how you can modify these choices, and also provides
+section describes how you can modify these choices and also provides
some guidelines on debugging optimized code.
@@ -1467,32 +1489,32 @@ Controlling Run-Time Checks
^^^^^^^^^^^^^^^^^^^^^^^^^^^
By default, GNAT generates all run-time checks, except stack overflow
-checks, and checks for access before elaboration on subprogram
-calls. The latter are not required in default mode, because all
+checks and checks for access before elaboration on subprogram
+calls. The latter are not required in default mode because all
necessary checking is done at compile time.
.. index:: -gnatp (gcc)
.. index:: -gnato (gcc)
-The gnat switch, :switch:`-gnatp` allows this default to be modified. See
+The GNAT switch, :switch:`-gnatp` allows you to modify this default; see
:ref:`Run-Time_Checks`.
Our experience is that the default is suitable for most development
purposes.
-Elaboration checks are off by default, and also not needed by default, since
-GNAT uses a static elaboration analysis approach that avoids the need for
-run-time checking. This manual contains a full chapter discussing the issue
-of elaboration checks, and if the default is not satisfactory for your use,
-you should read this chapter.
+Elaboration checks are off by default and also not needed by default
+since GNAT uses a static elaboration analysis approach that avoids the
+need for run-time checking. This manual contains a full chapter
+discussing the issue of elaboration checks and you should read this
+chapter if the default is not satisfactory for your use,
For validity checks, the minimal checks required by the Ada Reference
-Manual (for case statements and assignments to array elements) are on
-by default. These can be suppressed by use of the :switch:`-gnatVn` switch.
+Manual (for case statements and assignments to array elements) are enabled
+by default. You can suppress these by using the :switch:`-gnatVn` switch.
Note that in Ada 83, there were no validity checks, so if the Ada 83 mode
is acceptable (or when comparing GNAT performance with an Ada 83 compiler),
it may be reasonable to routinely use :switch:`-gnatVn`. Validity checks
-are also suppressed entirely if :switch:`-gnatp` is used.
+are also suppressed entirely if you use :switch:`-gnatp`.
.. index:: Overflow checks
.. index:: Checks, overflow
@@ -1503,9 +1525,9 @@ are also suppressed entirely if :switch:`-gnatp` is used.
.. index:: pragma Unsuppress
Note that the setting of the switches controls the default setting of
-the checks. They may be modified using either ``pragma Suppress`` (to
+the checks. You may modify them using either ``pragma Suppress`` (to
remove checks) or ``pragma Unsuppress`` (to add back suppressed
-checks) in the program source.
+checks) in your program source.
.. _Use_of_Restrictions:
@@ -1513,31 +1535,32 @@ checks) in the program source.
Use of Restrictions
^^^^^^^^^^^^^^^^^^^
-The use of pragma Restrictions allows you to control which features are
-permitted in your program. Apart from the obvious point that if you avoid
-relatively expensive features like finalization (enforceable by the use
-of pragma Restrictions (No_Finalization)), the use of this pragma does not
-affect the generated code in most cases.
+You can use pragma Restrictions to control which features are
+permitted in your program. In most cases, the use of this pragma
+itself does not affect the generated code (but, of course, if you
+avoid relatively expensive features like finalization, you'll have
+more efficient programs and that's enforceable by the use of pragma
+Restrictions (No_Finalization).
One notable exception to this rule is that the possibility of task abort
results in some distributed overhead, particularly if finalization or
-exception handlers are used. The reason is that certain sections of code
-have to be marked as non-abortable.
+exception handlers are used. This is because certain sections of code
+must be marked as non-abortable.
-If you use neither the ``abort`` statement, nor asynchronous transfer
-of control (``select ... then abort``), then this distributed overhead
-is removed, which may have a general positive effect in improving
-overall performance. Especially code involving frequent use of tasking
-constructs and controlled types will show much improved performance.
-The relevant restrictions pragmas are
+If you use neither the ``abort`` statement nor asynchronous transfer
+of control (``select ... then abort``), this distributed overhead can
+be removed, which may have a general positive effect in improving
+overall performance, especially in code involving frequent use of
+tasking constructs and controlled types, which will show much improved
+performance. The relevant restrictions pragmas are
.. code-block:: ada
pragma Restrictions (No_Abort_Statements);
pragma Restrictions (Max_Asynchronous_Select_Nesting => 0);
-It is recommended that these restriction pragmas be used if possible. Note
-that this also means that you can write code without worrying about the
+We recommend that you use these restriction pragmas if possible. If you do
+this, it also means you can write code without worrying about the
possibility of an immediate abort at any point.
@@ -1548,26 +1571,23 @@ Optimization Levels
.. index:: -O (gcc)
-Without any optimization option,
-the compiler's goal is to reduce the cost of
-compilation and to make debugging produce the expected results.
-Statements are independent: if you stop the program with a breakpoint between
-statements, you can then assign a new value to any variable or change
-the program counter to any other statement in the subprogram and get exactly
-the results you would expect from the source code.
+Without any optimization switch, the compiler's goal is to reduce the
+cost of compilation and to make debugging produce the expected
+results. This means that statements are independent: if you stop the
+program with a breakpoint between statements, you can then assign a
+new value to any variable or change the program counter to any other
+statement in the subprogram and get exactly the results you would
+expect from the source code. However, the generated programs are
+considerably larger and slower than when optimization is enabled.
Turning on optimization makes the compiler attempt to improve the
performance and/or code size at the expense of compilation time and
possibly the ability to debug the program.
-If you use multiple
--O options, with or without level numbers,
-the last such option is the one that is effective.
+If you use multiple :switch:`-O` switches, with or without level
+numbers, the last such switch is the one that's used.
-The default is optimization off. This results in the fastest compile
-times, but GNAT makes absolutely no attempt to optimize, and the
-generated programs are considerably larger and slower than when
-optimization is enabled. You can use the
+You can use the
:switch:`-O` switch (the permitted forms are :switch:`-O0`, :switch:`-O1`
:switch:`-O2`, :switch:`-O3`, and :switch:`-Os`)
to ``gcc`` to control the optimization level:
@@ -1576,24 +1596,26 @@ to ``gcc`` to control the optimization level:
* :switch:`-O0`
No optimization (the default);
generates unoptimized code but has
- the fastest compilation time.
+ the fastest compilation time. Debugging is easiest with this switch.
- Note that many other compilers do substantial optimization even
- if 'no optimization' is specified. With gcc, it is very unusual
- to use :switch:`-O0` for production if execution time is of any concern,
- since :switch:`-O0` means (almost) no optimization. This difference
- between gcc and other compilers should be kept in mind when
- doing performance comparisons.
+ Note that many other compilers do substantial optimization even if
+ 'no optimization' is specified. With GCC, it is very unusual to
+ use :switch:`-O0` for production if execution time is of any
+ concern, since :switch:`-O0` means (almost) no optimization. You
+ should keep this difference between GCC and other compilers in
+ mind when doing performance comparisons.
* :switch:`-O1`
- Moderate optimization;
- optimizes reasonably well but does not
- degrade compilation time significantly.
+ Moderate optimization; optimizes reasonably well but does not
+ degrade compilation time significantly. You may not be able to see
+ some variables in the debugger and changing the value of some
+ variables in the debugger may not have the effect you desire.
* :switch:`-O2`
Full optimization;
generates highly optimized code and has
- the slowest compilation time.
+ the slowest compilation time. You may see significant impacts on
+ your ability to display and modify variables in the debugger.
* :switch:`-O3`
Full optimization as in :switch:`-O2`;
@@ -1617,10 +1639,10 @@ of the optimization settings in general terms.
See the *Options That Control Optimization* section in
:title:`Using the GNU Compiler Collection (GCC)`
for details about
-the :switch:`-O` settings and a number of :switch:`-f` options that
+the :switch:`-O` settings and a number of :switch:`-f` switches that
individually enable or disable specific optimizations.
-Unlike some other compilation systems, ``gcc`` has
+Unlike some other compilation systems, GCC has
been tested extensively at all optimization levels. There are some bugs
which appear only with optimization turned on, but there have also been
bugs which show up only in *unoptimized* code. Selecting a lower
@@ -1628,7 +1650,7 @@ level of optimization does not improve the reliability of the code
generator, which in practice is highly reliable at all optimization
levels.
-Note regarding the use of :switch:`-O3`: The use of this optimization level
+A note regarding the use of :switch:`-O3`: The use of this optimization level
ought not to be automatically preferred over that of level :switch:`-O2`,
since it often results in larger executables which may run more slowly.
See further discussion of this point in :ref:`Inlining_of_Subprograms`.
@@ -1678,10 +1700,10 @@ These are the most common cases:
may not be able to stop on what looks like a statement.
- *Invariant code motion:* moving an expression that does not change within a
- loop, to the beginning of the loop.
+ loop to the beginning of the loop.
- *Instruction scheduling:* moving instructions so as to
- overlap loads and stores (typically) with other code, or in
+ overlap loads and stores (typically) with other code or in
general to move computations of values closer to their uses. Often
this causes you to pass an assignment statement without the assignment
happening and then later bounce back to the statement when the
@@ -1703,7 +1725,7 @@ These are the most common cases:
- In a subprogram prologue, a parameter may not yet have been moved to its
'home'.
- - A variable may be dead, and its register re-used. This is
+ - A variable may be dead and its register re-used. This is
probably the most common cause.
- As mentioned above, the assignment of a value to a variable may
@@ -1715,14 +1737,14 @@ These are the most common cases:
In general, when an unexpected value appears for a local variable or parameter
you should first ascertain if that value was actually computed by
- your program, as opposed to being incorrectly reported by the debugger.
+ your program as opposed to being incorrectly reported by the debugger.
Record fields or
array elements in an object designated by an access value
- are generally less of a problem, once you have ascertained that the access
+ are generally less of a problem once you have verified that the access
value is sensible.
Typically, this means checking variables in the preceding code and in the
calling subprogram to verify that the value observed is explainable from other
- values (one must apply the procedure recursively to those
+ values (you must apply the procedure recursively to those
other values); or re-running the code and stopping a little earlier
(perhaps before the call) and stepping to better see how the variable obtained
the value in question; or continuing to step *from* the point of the
@@ -1750,8 +1772,8 @@ following conditions are met:
* The optimization level is at least :switch:`-O1`.
-* The called subprogram is suitable for inlining: It must be small enough
- and not contain something that ``gcc`` cannot support in inlined
+* The called subprogram is suitable for inlining: it must be small enough
+ and not contain something that the backend cannot support in inlined
subprograms.
.. index:: pragma Inline
@@ -1760,16 +1782,17 @@ following conditions are met:
* Any one of the following applies: ``pragma Inline`` is applied to the
subprogram; the subprogram is local to the unit and called once from
within it; the subprogram is small and optimization level :switch:`-O2` is
- specified; optimization level :switch:`-O3` is specified.
+ specified; optimization level :switch:`-O3` is specified; or the subprogram
+ is an expression function.
Calls to subprograms in |withed| units are normally not inlined.
-To achieve actual inlining (that is, replacement of the call by the code
+To achieve inlining in those case (that is, replacement of the call by the code
in the body of the subprogram), the following conditions must all be true:
* The optimization level is at least :switch:`-O1`.
* The called subprogram is suitable for inlining: It must be small enough
- and not contain something that ``gcc`` cannot support in inlined
+ and not contain something that the backend cannot support in inlined
subprograms.
* There is a ``pragma Inline`` for the subprogram.
@@ -1777,7 +1800,7 @@ in the body of the subprogram), the following conditions must all be true:
* The :switch:`-gnatn` switch is used on the command line.
Even if all these conditions are met, it may not be possible for
-the compiler to inline the call, due to the length of the body,
+the compiler to inline the call due to the length of the body,
or features in the body that make it impossible for the compiler
to do the inlining.
@@ -1813,7 +1836,7 @@ is compiled, the call will be inlined if the body of ``Q`` is small
enough, but now ``Main`` depends on the body of ``R`` in
:file:`r.adb` as well as on the spec. This means that if this body is edited,
the main program must be recompiled. Note that this extra dependency
-occurs whether or not the call is in fact inlined by ``gcc``.
+occurs whether or not the call is in fact inlined by the backend.
The use of front end inlining with :switch:`-gnatN` generates similar
additional dependencies.
@@ -1821,42 +1844,45 @@ additional dependencies.
.. index:: -fno-inline (gcc)
Note: The :switch:`-fno-inline` switch overrides all other conditions and ensures that
-no inlining occurs, unless requested with pragma Inline_Always for ``gcc``
+no inlining occurs, unless requested with pragma Inline_Always for most
back-ends. The extra dependences resulting from :switch:`-gnatn` will still be active,
even if this switch is used to suppress the resulting inlining actions.
.. index:: -fno-inline-functions (gcc)
-Note: The :switch:`-fno-inline-functions` switch can be used to prevent
-automatic inlining of subprograms if :switch:`-O3` is used.
+For the GCC backend, you can use the
+:switch:`-fno-inline-functions` switch to prevent automatic inlining
+of subprograms if you use :switch:`-O3`.
.. index:: -fno-inline-small-functions (gcc)
-Note: The :switch:`-fno-inline-small-functions` switch can be used to prevent
-automatic inlining of small subprograms if :switch:`-O2` is used.
+For the GCC backend, you can use the
+:switch:`-fno-inline-small-functions` switch to prevent automatic
+inlining of small subprograms if you use :switch:`-O2`.
.. index:: -fno-inline-functions-called-once (gcc)
-Note: The :switch:`-fno-inline-functions-called-once` switch
-can be used to prevent inlining of subprograms local to the unit
-and called once from within it if :switch:`-O1` is used.
+For the GC backend, you can use the
+:switch:`-fno-inline-functions-called-once` switch to prevent inlining
+of subprograms local to the unit and called once from within it if you
+use :switch:`-O1`.
-Note regarding the use of :switch:`-O3`: :switch:`-gnatn` is made up of two
-sub-switches :switch:`-gnatn1` and :switch:`-gnatn2` that can be directly
-specified in lieu of it, :switch:`-gnatn` being translated into one of them
+A note regarding the use of :switch:`-O3`: :switch:`-gnatn` is made up of two
+sub-switches :switch:`-gnatn1` and :switch:`-gnatn2` that you can directly
+specify. :switch:`-gnatn` is translated into one of them
based on the optimization level. With :switch:`-O2` or below, :switch:`-gnatn`
is equivalent to :switch:`-gnatn1` which activates pragma ``Inline`` with
moderate inlining across modules. With :switch:`-O3`, :switch:`-gnatn` is
equivalent to :switch:`-gnatn2` which activates pragma ``Inline`` with
full inlining across modules. If you have used pragma ``Inline`` in
-appropriate cases, then it is usually much better to use :switch:`-O2`
+appropriate cases, it's usually much better to use :switch:`-O2`
and :switch:`-gnatn` and avoid the use of :switch:`-O3` which has the additional
effect of inlining subprograms you did not think should be inlined. We have
found that the use of :switch:`-O3` may slow down the compilation and increase
the code size by performing excessive inlining, leading to increased
instruction cache pressure from the increased code size and thus minor
-performance improvements. So the bottom line here is that you should not
-automatically assume that :switch:`-O3` is better than :switch:`-O2`, and
+performance degradations. So the bottom line here is that you should not
+automatically assume that :switch:`-O3` is better than :switch:`-O2` and
indeed you should use :switch:`-O3` only if tests show that it actually
improves performance for your program.
@@ -1867,43 +1893,42 @@ Floating Point Operations
.. index:: Floating-Point Operations
-On almost all targets, GNAT maps Float and Long_Float to the 32-bit and
-64-bit standard IEEE floating-point representations, and operations will
+On almost all targets, GNAT maps ``Float`` and ``Long_Float`` to the 32-bit and
+64-bit standard IEEE floating-point representations and operations will
use standard IEEE arithmetic as provided by the processor. On most, but
-not all, architectures, the attribute Machine_Overflows is False for these
+not all, architectures, the attribute ``Machine_Overflows`` is ``False`` for these
types, meaning that the semantics of overflow is implementation-defined.
In the case of GNAT, these semantics correspond to the normal IEEE
treatment of infinities and NaN (not a number) values. For example,
1.0 / 0.0 yields plus infinitiy and 0.0 / 0.0 yields a NaN. By
avoiding explicit overflow checks, the performance is greatly improved
-on many targets. However, if required, floating-point overflow can be
-enabled by the use of the pragma Check_Float_Overflow.
+on many targets. However, if required, you can enable floating-point overflow
+by using the pragma ``Check_Float_Overflow``.
Another consideration that applies specifically to x86 32-bit
architectures is which form of floating-point arithmetic is used.
-By default the operations use the old style x86 floating-point,
+By default, the operations use the old style x86 floating-point,
which implements an 80-bit extended precision form (on these
-architectures the type Long_Long_Float corresponds to that form).
+architectures the type ``Long_Long_Float`` corresponds to that form).
In addition, generation of efficient code in this mode means that
-the extended precision form will be used for intermediate results.
+the extended precision form is used for intermediate results.
This may be helpful in improving the final precision of a complex
-expression. However it means that the results obtained on the x86
-will be different from those on other architectures, and for some
+expression, but it means that the results obtained on the x86
+may be different from those on other architectures and, for some
algorithms, the extra intermediate precision can be detrimental.
In addition to this old-style floating-point, all modern x86 chips
implement an alternative floating-point operation model referred
-to as SSE2. In this model there is no extended form, and furthermore
+to as SSE2. In this model, there is no extended form and
execution performance is significantly enhanced. To force GNAT to use
this more modern form, use both of the switches:
-msse2 -mfpmath=sse
A unit compiled with these switches will automatically use the more
-efficient SSE2 instruction set for Float and Long_Float operations.
+efficient SSE2 instruction set for ``Float`` and ``Long_Float`` operations.
Note that the ABI has the same form for both floating-point models,
-so it is permissible to mix units compiled with and without these
-switches.
+so you can mix units compiled with and without these switches.
@@ -1916,17 +1941,20 @@ Vectorization of loops
.. index:: Optimization Switches
-You can take advantage of the auto-vectorizer present in the ``gcc``
-back end to vectorize loops with GNAT. The corresponding command line switch
-is :switch:`-ftree-vectorize` but, as it is enabled by default at :switch:`-O3`
-and other aggressive optimizations helpful for vectorization also are enabled
-by default at this level, using :switch:`-O3` directly is recommended.
-
-You also need to make sure that the target architecture features a supported
-SIMD instruction set. For example, for the x86 architecture, you should at
-least specify :switch:`-msse2` to get significant vectorization (but you don't
-need to specify it for x86-64 as it is part of the base 64-bit architecture).
-Similarly, for the PowerPC architecture, you should specify :switch:`-maltivec`.
+The GCC and LLVM backends have an auto-vectorizer that's enabled by
+default at some optimization levels. For the GCC backend, it's
+enabled by default at :switch:`-O3` and you can request it at other
+levels with :switch:`-ftree-vectorize`. For the LLVM backend, it's
+enabled by default at lower levels, but you can explicitly enable or
+disable it with the :switch:`-fno-vectorize`, :switch:`-fvectorize`,
+:switch:`-fno-slp-vectorize`, and :switch:`-fslp-vectorize` switches.
+
+To get auto-vectorization, you also need to make sure that the target
+architecture features a supported SIMD instruction set. For example,
+for the x86 architecture, you should at least specify :switch:`-msse2`
+to get significant vectorization (but you don't need to specify it for
+x86-64 as it is part of the base 64-bit architecture). Similarly, for
+the PowerPC architecture, you should specify :switch:`-maltivec`.
The preferred loop form for vectorization is the ``for`` iteration scheme.
Loops with a ``while`` iteration scheme can also be vectorized if they are
@@ -1950,7 +1978,7 @@ contain a single nested loop, if it can be vectorized when considered alone:
end Sum;
The vectorizable operations depend on the targeted SIMD instruction set, but
-the adding and some of the multiplying operators are generally supported, as
+addition and some multiplication operators are generally supported, as
well as the logical operators for modular types. Note that compiling
with :switch:`-gnatp` might well reveal cases where some checks do thwart
vectorization.
@@ -1993,11 +2021,11 @@ or unconstrained array types:
The quality of the generated code decreases when the dynamic aspect of the
array type increases, the worst code being generated for unconstrained array
-types. This is so because, the less information the compiler has about the
+types. This is because the less information the compiler has about the
bounds of the array, the more fallback code it needs to generate in order to
fix things up at run time.
-It is possible to specify that a given loop should be subject to vectorization
+You can specify that a given loop should be subject to vectorization
preferably to other optimizations by means of pragma ``Loop_Optimize``:
.. code-block:: ada
@@ -2005,9 +2033,10 @@ preferably to other optimizations by means of pragma ``Loop_Optimize``:
pragma Loop_Optimize (Vector);
placed immediately within the loop will convey the appropriate hint to the
-compiler for this loop.
+compiler for this loop. This is currently only supported for the GCC
+backend.
-It is also possible to help the compiler generate better vectorized code
+You can also help the compiler generate better vectorized code
for a given loop by asserting that there are no loop-carried dependencies
in the loop. Consider for example the procedure:
@@ -2036,6 +2065,7 @@ be overcome by another hint:
placed immediately within the loop will tell the compiler that it can safely
omit the non-vectorized version of the loop as well as the run-time test.
+This is also currently only supported by the GCC backend.
.. _Other_Optimization_Switches:
@@ -2045,15 +2075,16 @@ Other Optimization Switches
.. index:: Optimization Switches
-Since GNAT uses the ``gcc`` back end, all the specialized
-``gcc`` optimization switches are potentially usable. These switches
-have not been extensively tested with GNAT but can generally be expected
-to work. Examples of switches in this category are :switch:`-funroll-loops`
-and the various target-specific :switch:`-m` options (in particular, it has
-been observed that :switch:`-march=xxx` can significantly improve performance
-on appropriate machines). For full details of these switches, see
-the *Submodel Options* section in the *Hardware Models and Configurations*
-chapter of :title:`Using the GNU Compiler Collection (GCC)`.
+You can also use any specialized optimization switches supported by
+the backend being used. These switches have not been extensively
+tested with GNAT but can generally be expected to work. Examples of
+switches in this category for the GCC backend are
+:switch:`-funroll-loops` and the various target-specific :switch:`-m`
+options (in particular, it has been observed that :switch:`-march=xxx`
+can significantly improve performance on appropriate machines). For
+full details of these switches, see the *Submodel Options* section in
+the *Hardware Models and Configurations* chapter of :title:`Using the
+GNU Compiler Collection (GCC)`.
.. _Optimization_and_Strict_Aliasing:
@@ -2091,7 +2122,7 @@ the following example:
...
end;
-In this example, since ``V2`` can only access objects of type ``Int2``
+Here, since ``V2`` can only access objects of type ``Int2``
and ``I1`` is not one of them, there is no possibility that the assignment
to ``V2.all`` affects the value of ``I1``. This means that the compiler
optimizer can infer that the value ``I1`` is constant for all iterations
@@ -2100,12 +2131,13 @@ instead of in every iteration (this is called load hoisting).
This kind of optimizations, based on strict type-based aliasing, is
triggered by specifying an optimization level of :switch:`-O2` or
-higher (or :switch:`-Os`) and allows the compiler to generate more
+higher (or :switch:`-Os`) for the GCC backend and :switch:`-O1` or higher for the
+LLVM backend and allows the compiler to generate more
efficient code.
However, although this optimization is always correct in terms of
-the formal semantics of the Ada Reference Manual, difficulties can
-arise if features like ``Unchecked_Conversion`` are used to break
+the formal semantics of the Ada Reference Manual, you can run into difficulties
+arise if you use features like ``Unchecked_Conversion`` to break
the typing system. Consider the following complete program example:
.. code-block:: ada
@@ -2145,7 +2177,7 @@ the typing system. Consider the following complete program example:
Put_Line (Int1'Image (V1.all));
end;
-This program prints out ``0`` in :switch:`-O0` or :switch:`-O1` modes,
+This program prints out ``0`` in :switch:`-O0` mode,
but it prints out ``1`` in :switch:`-O2` mode. That's because in strict
aliasing mode, the compiler may and does assume that the assignment to
``V2.all`` could not affect the value of ``V1.all``, since different
@@ -2160,12 +2192,12 @@ does not point to an object of type ``Int2``. This means that the effect
is entirely unpredictable.
However, although that explanation may satisfy a language lawyer, in
-practice an application programmer expects an unchecked conversion
+practice, you probably expect an unchecked conversion
involving pointers to create true aliases and the behavior of printing
``1`` is questionable. In this case, the strict type-based aliasing
optimizations are clearly unwelcome.
-Indeed the compiler recognizes this possibility and the instantiation of
+Indeed, the compiler recognizes this possibility and the instantiation of
Unchecked_Conversion generates a warning:
::
@@ -2182,26 +2214,26 @@ the suspicious instance of ``Unchecked_Conversion``.
As implied by the warning message, there are approaches you can use to
avoid the unwanted strict aliasing optimizations in a case like this.
-One possibility is to simply avoid the use of :switch:`-O2`, but
-that is quite drastic, since it throws away a number of useful
-optimizations that do not involve strict aliasing assumptions.
+One possibility is to simply avoid the use of higher levels of optimization,
+but that is quite drastic, since it throws away a number of useful
+optimizations that don't involve strict aliasing assumptions.
-A less drastic approach is to compile the program using the
-option :switch:`-fno-strict-aliasing`. Actually it is only the
+A less drastic approach is for you to compile the program using the
+:switch:`-fno-strict-aliasing` switch. Actually, it is only the
unit containing the dereferencing of the suspicious pointer
-that needs to be compiled. So in this case, if we compile
-unit ``M`` with this switch, then we get the expected
-value of zero printed. Analyzing which units might need
-the switch can be painful, so a more reasonable approach
+that you need to compile with that switch. So, in this case, if you compile
+unit ``M`` with this switch, you get the expected
+value of ``0`` printed. Analyzing which units might need
+the switch can be painful, so you may find it a more reasonable approach
is to compile the entire program with options :switch:`-O2`
-and :switch:`-fno-strict-aliasing`. If the performance is
-satisfactory with this combination of options, then the
-advantage is that the entire issue of possible problematic
-optimizations due to strict aliasing is avoided.
-
-To avoid the use of compiler switches, the configuration
-pragma ``No_Strict_Aliasing`` with no parameters may be
-used to specify that for all access types, the strict
+and :switch:`-fno-strict-aliasing`. If you obtain satisfactory performance
+with this combination of options, then the
+advantage is that you have avoided the entire issue of possible problematic
+optimizations due to strict aliasing.
+
+To avoid the use of compiler switches, you may use the configuration
+pragma ``No_Strict_Aliasing`` with no parameters
+to specify that for all access types, the strict
aliasing optimizations should be suppressed.
However, these approaches are still overkill, in that they cause
@@ -2211,16 +2243,16 @@ access type identified as problematic.
The first possibility is to move the instantiation of unchecked
conversion to the unit in which the type is declared. In this
-example, we would move the instantiation of ``Unchecked_Conversion``
+example, you would move the instantiation of ``Unchecked_Conversion``
from the body of package ``P2`` to the spec of package ``P1``.
-Now the warning disappears because any use of the access type
-knows there is a suspicious unchecked conversion, and the strict
+Now, the warning disappears because any use of the access type
+knows there is a suspicious unchecked conversion and the strict
aliasing optimizations are automatically suppressed for it.
-If it is not practical to move the unchecked conversion to the same unit
+If it's not practical to move the unchecked conversion to the same unit
in which the destination access type is declared (perhaps because the
-source type is not visible in that unit), the second possibiliy is to
-use pragma ``No_Strict_Aliasing`` for the type. This pragma must occur
+source type is not visible in that unit), the second possibiliy is for you to
+use pragma ``No_Strict_Aliasing`` for the type. You must place this pragma
in the same declarative part as the declaration of the access type:
.. code-block:: ada
@@ -2242,13 +2274,13 @@ type in the universe, by using pragma ``Universal_Aliasing``:
pragma Universal_Aliasing (Int2);
The effect is equivalent to applying pragma ``No_Strict_Aliasing`` to
-every access type designating ``Int2``, in particular ``A2``, and more
-generally to every reference made to an object of declared type ``Int2``,
-so it is very powerful and effectively takes ``Int2`` out of the alias
+every access type designating ``Int2``, in particular ``A2``, and, more
+generally, to every reference made to an object of declared type ``Int2``,
+so it's very powerful and effectively takes ``Int2`` out of the alias
analysis performed by the compiler in all circumstances.
-This pragma can also be used to deal with aliasing issues that arise
-again from the use of ``Unchecked_Conversion`` in the source code but
+You can also use this pragma used to deal with aliasing issues that arise
+from the use of ``Unchecked_Conversion`` in the source code but
without the presence of access types. The typical example is code
that streams data by means of arrays of storage units (bytes):
@@ -2281,12 +2313,12 @@ This generates the following warning for the call to ``Send``:
dump.adb:8:25: warning: to enable RM 13.9(12) implementation permission
This occurs because the formal parameter ``S`` of ``Send`` is passed by
-reference by the compiler and it is not possible to pass a reference to
+reference by the compiler and it's not possible to pass a reference to
``R`` directly in the call without violating strict type-based aliasing.
That's why the compiler generates a temporary of type ``Chunk_Of_Bytes``
just before the call and passes a reference to this temporary instead.
-As implied by the warning message, it is possible to avoid the temporary
+As implied by the warning message, you can avoid the temporary
(and the warning) by means of pragma ``Universal_Aliasing``:
.. code-block:: ada
@@ -2294,7 +2326,7 @@ As implied by the warning message, it is possible to avoid the temporary
type Chunk_Of_Bytes is array (1 .. 64) of Byte;
pragma Universal_Aliasing (Chunk_Of_Bytes);
-The pragma can also be applied to the component type instead:
+You can also apply this pragma to the component type instead:
.. code-block:: ada
@@ -2304,18 +2336,18 @@ The pragma can also be applied to the component type instead:
and every array type whose component is ``Byte`` will inherit the pragma.
-To sum up, the alias analysis performed in strict aliasing mode by the
-compiler can have significant benefits. We have seen cases of large scale
-application code where the execution time is increased by up to 5% when
-these optimizations are turned off. However, if you have code that make
-significant use of unchecked conversion, you might want to just stick
-with :switch:`-O1` and avoid the entire issue. If you get adequate
-performance at this level of optimization, that's probably the safest
-approach. If tests show that you really need higher levels of
-optimization, then you can experiment with :switch:`-O2` and
-:switch:`-O2 -fno-strict-aliasing` to see how much effect this
-has on size and speed of the code. If you really need to use
-:switch:`-O2` with strict aliasing in effect, then you should
+To summarize, the alias analysis performed in strict aliasing mode by
+the compiler can have significant benefits. We've seen cases of large
+scale application code where the execution time is increased by up to
+5% when these optimizations are turned off. However, if you have code
+that make significant use of unchecked conversion, you might want to
+just stick with :switch:`-O1` (with the GCC backend) and avoid the
+entire issue. If you get adequate performance at this level of
+optimization, that's probably the safest approach. If tests show that
+you really need higher levels of optimization, then you can experiment
+with :switch:`-O2` and :switch:`-O2 -fno-strict-aliasing` to see how
+much effect this has on size and speed of the code. If you really need
+to use :switch:`-O2` with strict aliasing in effect, then you should
review any uses of unchecked conversion, particularly if you are
getting the warnings described above.
@@ -2327,12 +2359,12 @@ Aliased Variables and Optimization
.. index:: Aliasing
-There are scenarios in which programs may
+There are scenarios in which your programs may
use low level techniques to modify variables
that otherwise might be considered to be unassigned. For example,
-a variable can be passed to a procedure by reference, which takes
-the address of the parameter and uses the address to modify the
-variable's value, even though it is passed as an IN parameter.
+you can pass a variable to a procedure by reference by taking
+the address of the parameter and using that address to modify the
+variable's value, even though the address is passed as an ``in`` parameter.
Consider the following example:
.. code-block:: ada
@@ -2359,21 +2391,23 @@ Consider the following example:
Get_String (Temp, Max_Length);
end;
-where Get_String is a C function that uses the address in Temp to
+where Get_String is a C function that uses the address in ``Temp`` to
modify the variable ``Name``. This code is dubious, and arguably
-erroneous, and the compiler would be entitled to assume that
+erroneous, and the compiler is entitled to assume that
``Name`` is never modified, and generate code accordingly.
-However, in practice, this would cause some existing code that
-seems to work with no optimization to start failing at high
+However, in practice, this could cause some existing code that
+seems to work with no optimization to start failing at higher
levels of optimization.
-What the compiler does for such cases is to assume that marking
-a variable as aliased indicates that some "funny business" may
-be going on. The optimizer recognizes the aliased keyword and
-inhibits optimizations that assume the value cannot be assigned.
-This means that the above example will in fact "work" reliably,
-that is, it will produce the expected results.
+What the compiler does for such cases, is to assume that marking a
+variable as aliased indicates that some "funny business" may be going
+on. The optimizer recognizes the ``aliased`` keyword and inhibits any
+optimizations that assume the variable cannot be assigned to. This
+means that the above example will in fact "work" reliably, that is, it
+will produce the expected results. However, you should nevertheless
+avoid code such as this if possible because it's not portable and may not
+functin as you expect with all compilers.
.. _Atomic_Variables_and_Optimization:
@@ -2383,19 +2417,19 @@ Atomic Variables and Optimization
.. index:: Atomic
-There are two considerations with regard to performance when
-atomic variables are used.
+You need to take two things into consideration with regard to performance when
+you use atomic variables.
First, the RM only guarantees that access to atomic variables
-be atomic, it has nothing to say about how this is achieved,
+be atomic, but has nothing to say about how this is achieved,
though there is a strong implication that this should not be
-achieved by explicit locking code. Indeed GNAT will never
-generate any locking code for atomic variable access (it will
+achieved by explicit locking code. Indeed, GNAT never
+generates any locking code for atomic variable access; it will
simply reject any attempt to make a variable or type atomic
-if the atomic access cannot be achieved without such locking code).
+if the atomic access cannot be achieved without such locking code.
-That being said, it is important to understand that you cannot
-assume that the entire variable will always be accessed. Consider
+That being said, it's important to understand that you cannot
+assume the the program will always access the entire variable. Consider
this example:
.. code-block:: ada
@@ -2414,8 +2448,8 @@ this example:
You cannot assume that the reference to ``RV.B``
will read the entire 32-bit
-variable with a single load instruction. It is perfectly legitimate if
-the hardware allows it to do a byte read of just the B field. This read
+variable with a single load instruction. It is perfectly legitimate, if
+the hardware allows it, to do a byte read of just the ``B`` field. This read
is still atomic, which is all the RM requires. GNAT can and does take
advantage of this, depending on the architecture and optimization level.
Any assumption to the contrary is non-portable and risky. Even if you
@@ -2434,10 +2468,10 @@ as in:
X := RV_Copy.B;
end;
-Now the reference to RV must read the whole variable.
-Actually one can imagine some compiler which figures
+Now the reference to ``RV`` must read the whole variable.
+Actually, one can imagine some compiler which figures
out that the whole copy is not required (because only
-the B field is actually accessed), but GNAT
+the ``B`` field is actually accessed), but GNAT
certainly won't do that, and we don't know of any
compiler that would not handle this right, and the
above code will in practice work portably across
@@ -2447,8 +2481,8 @@ The second issue with atomic variables has to do with
the possible requirement of generating synchronization
code. For more details on this, consult the sections on
the pragmas Enable/Disable_Atomic_Synchronization in the
-GNAT Reference Manual. If performance is critical, and
-such synchronization code is not required, it may be
+:title:``GNAT Reference Manual``. If performance is critical, and
+such synchronization code is not required, you may find it
useful to disable it.
@@ -2459,43 +2493,43 @@ Passive Task Optimization
.. index:: Passive Task
-A passive task is one which is sufficiently simple that
-in theory a compiler could recognize it an implement it
+A passive task is one which is sufficiently simple that,
+in theory, a compiler could recognize it and implement it
efficiently without creating a new thread. The original design
of Ada 83 had in mind this kind of passive task optimization, but
-only a few Ada 83 compilers attempted it. The problem was that
+only a few Ada 83 compilers attempted it. The reason was that
it was difficult to determine the exact conditions under which
the optimization was possible. The result is a very fragile
optimization where a very minor change in the program can
suddenly silently make a task non-optimizable.
With the revisiting of this issue in Ada 95, there was general
-agreement that this approach was fundamentally flawed, and the
+agreement that this approach was fundamentally flawed and the
notion of protected types was introduced. When using protected
-types, the restrictions are well defined, and you KNOW that the
+types, the restrictions are well defined, you KNOW that the
operations will be optimized, and furthermore this optimized
performance is fully portable.
Although it would theoretically be possible for GNAT to attempt to
-do this optimization, but it really doesn't make sense in the
-context of Ada 95, and none of the Ada 95 compilers implement
-this optimization as far as we know. In particular GNAT never
+do this optimization, it really doesn't make sense in the
+context of Ada 95 and none of the Ada 95 compilers implement
+this optimization as far as we know. GNAT never
attempts to perform this optimization.
-In any new Ada 95 code that is written, you should always
+In any new Ada 95 code that you write, you should always
use protected types in place of tasks that might be able to
be optimized in this manner.
-Of course this does not help if you have legacy Ada 83 code
+Of course, this does not help if you have legacy Ada 83 code
that depends on this optimization, but it is unusual to encounter
a case where the performance gains from this optimization
are significant.
Your program should work correctly without this optimization. If
-you have performance problems, then the most practical
+you have performance problems, the most practical
approach is to figure out exactly where these performance problems
-arise, and update those particular tasks to be protected types. Note
-that typically clients of the tasks who call entries, will not have
-to be modified, only the task definition itself.
+arise and update those particular tasks to be protected types. Note
+that typically clients of the tasks who call entries will not have
+to be modified, only the task definitions themselves.
.. _Text_IO_Suggestions:
@@ -2505,20 +2539,20 @@ to be modified, only the task definition itself.
.. index:: Text_IO and performance
-The ``Ada.Text_IO`` package has fairly high overheads due in part to
+The ``Ada.Text_IO`` package has fairly high overhead due in part to
the requirement of maintaining page and line counts. If performance
-is critical, a recommendation is to use ``Stream_IO`` instead of
-``Text_IO`` for volume output, since this package has less overhead.
+is critical, one recommendation is to use ``Stream_IO`` instead of
+``Text_IO`` for large-volume output, since it has less overhead.
-If ``Text_IO`` must be used, note that by default output to the standard
-output and standard error files is unbuffered (this provides better
-behavior when output statements are used for debugging, or if the
-progress of a program is observed by tracking the output, e.g. by
+If you must use ``Text_IO``, note that output to the standard output and
+standard error files is unbuffered by default (this provides
+better behavior when output statements are used for debugging or if
+the progress of a program is observed by tracking the output, e.g. by
using the Unix *tail -f* command to watch redirected output).
-If you are generating large volumes of output with ``Text_IO`` and
+If you're generating large volumes of output with ``Text_IO`` and
performance is an important factor, use a designated file instead
-of the standard output file, or change the standard output file to
+of the standard output file or change the standard output file to
be buffered using ``Interfaces.C_Streams.setvbuf``.
@@ -2537,16 +2571,14 @@ your executable just by setting options at compilation time.
About unused subprogram/data elimination
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-By default, an executable contains all code and data of its composing objects
+By default, an executable contains all code and data of its objects
(directly linked or coming from statically linked libraries), even data or code
-never used by this executable.
+never used by this executable. This feature eliminates such unused code from your
+executable, thus making it smaller (in disk and in memory).
-This feature will allow you to eliminate such unused code from your
-executable, making it smaller (in disk and in memory).
-
-This functionality is available on all Linux platforms except for the IA-64
+You can use this functionality on all Linux platforms except for the IA-64
architecture and on all cross platforms using the ELF binary file format.
-In both cases GNU binutils version 2.16 or later are required to enable it.
+In both cases, GNU binutils version 2.16 or later are required to enable it.
.. _Compilation_options:
@@ -2560,31 +2592,33 @@ is directly performed by the linker.
.. index:: -fdata-sections (gcc)
In order to do this, it has to work with objects compiled with the
-following options:
+following switches passed to the GCC backend:
:switch:`-ffunction-sections` :switch:`-fdata-sections`.
These options are usable with C and Ada files.
-They will place respectively each
+They cause the compiler to place each
function or data in a separate section in the resulting object file.
-Once the objects and static libraries are created with these options, the
-linker can perform the dead code elimination. You can do this by setting
-the :switch:`-Wl,--gc-sections` option to gcc command or in the
-:switch:`-largs` section of ``gnatmake``. This will perform a
-garbage collection of code and data never referenced.
+Once you've created the objects and static libraries with these switches, the
+linker can perform the dead code elimination. You can do this by specifying
+the :switch:`-Wl,--gc-sections` switch to your ``gcc`` command or in the
+:switch:`-largs` section of your invocation of ``gnatmake``. This causes
+the linker to perform a
+garbage collection and remove code and data that are never referenced.
-If the linker performs a partial link (:switch:`-r` linker option), then you
-will need to provide the entry point using the :switch:`-e` / :switch:`--entry`
-linker option.
+If the linker performs a partial link (:switch:`-r` linker switch), then you
+need to provide the entry point using the :switch:`-e` / :switch:`--entry`
+linker switch.
Note that objects compiled without the :switch:`-ffunction-sections` and
:switch:`-fdata-sections` options can still be linked with the executable.
-However, no dead code elimination will be performed on those objects (they will
+However, no dead code elimination can be performed on those objects (they will
be linked as is).
-The GNAT static library is now compiled with -ffunction-sections and
--fdata-sections on some platforms. This allows you to eliminate the unused code
-and data of the GNAT library from your executable.
+The GNAT static library is compiled with :switch:`-ffunction-sections`
+and :switch:`-fdata-sections` on some platforms. This allows you to
+eliminate the unused code and data of the GNAT library from your
+executable.
.. _Example_of_unused_subprogram/data_elimination:
@@ -2592,7 +2626,7 @@ and data of the GNAT library from your executable.
Example of unused subprogram/data elimination
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Here is a simple example:
+Here's a simple example:
.. code-block:: ada
@@ -2624,7 +2658,7 @@ Here is a simple example:
end Aux;
``Unused`` and ``Unused_Data`` are never referenced in this code
-excerpt, and hence they may be safely removed from the final executable.
+excerpt and hence may be safely removed from the final executable.
::
@@ -2643,9 +2677,9 @@ excerpt, and hence they may be safely removed from the final executable.
02005350 T aux__used
0201ffe0 B aux__used_data
-It can be observed that the procedure ``Unused`` and the object
-``Unused_Data`` are removed by the linker when using the
-appropriate options.
+You can see that the procedure ``Unused`` and the object
+``Unused_Data`` are removed by the linker when you've used the
+appropriate switches.
.. index:: Overflow checks
@@ -2672,12 +2706,12 @@ that intermediate results are not out of range. For example:
...
A := A + 1;
-If ``A`` has the value ``Integer'Last``, then the addition may cause
+If ``A`` has the value ``Integer'Last``, the addition will cause
overflow since the result is out of range of the type ``Integer``.
-In this case ``Constraint_Error`` will be raised if checks are
+In this case, execution will raise ``Constraint_Error`` if checks are
enabled.
-A trickier situation arises in examples like the following:
+A trickier situation arises in cases like the following:
.. code-block:: ada
@@ -2686,12 +2720,12 @@ A trickier situation arises in examples like the following:
A := (A + 1) + C;
where ``A`` is ``Integer'Last`` and ``C`` is ``-1``.
-Now the final result of the expression on the right hand side is
+Here, the final result of the expression on the right hand side is
``Integer'Last`` which is in range, but the question arises whether the
intermediate addition of ``(A + 1)`` raises an overflow error.
The (perhaps surprising) answer is that the Ada language
-definition does not answer this question. Instead it leaves
+definition does not answer this question. Instead, it leaves
it up to the implementation to do one of two things if overflow
checks are enabled.
@@ -2700,27 +2734,27 @@ checks are enabled.
* yield the correct mathematical result which is then used in
subsequent operations.
-If the compiler chooses the first approach, then the assignment of this
+If the compiler chooses the first approach, the execution of this
example will indeed raise ``Constraint_Error`` if overflow checking is
-enabled, or result in erroneous execution if overflow checks are suppressed.
+enabled or result in erroneous execution if overflow checks are suppressed.
But if the compiler
-chooses the second approach, then it can perform both additions yielding
+chooses the second approach, it can perform both additions yielding
the correct mathematical result, which is in range, so no exception
-will be raised, and the right result is obtained, regardless of whether
+is raised and the right result is obtained, regardless of whether
overflow checks are suppressed.
-Note that in the first example an
+Note that in the first example, an
exception will be raised in either case, since if the compiler
gives the correct mathematical result for the addition, it will
-be out of range of the target type of the assignment, and thus
+be out of range of the target type of the assignment and thus
fails the range check.
This lack of specified behavior in the handling of overflow for
-intermediate results is a source of non-portability, and can thus
-be problematic when programs are ported. Most typically this arises
-in a situation where the original compiler did not raise an exception,
-and then the application is moved to a compiler where the check is
+intermediate results is a source of non-portability and can thus
+be problematic when you port programs. Most typically, this arises
+in a situation where the original compiler did not raise an exception
+and you move the application to a compiler where the check is
performed on the intermediate result and an unexpected exception is
raised.
@@ -2732,11 +2766,11 @@ assertion forms, another issue arises. Consider:
procedure P (A, B : Integer) with
Pre => A + B <= Integer'Last;
-One often wants to regard arithmetic in a context like this from
-a mathematical point of view. So for example, if the two actual parameters
-for a call to ``P`` are both ``Integer'Last``, then
-the precondition should be regarded as False. If we are executing
-in a mode with run-time checks enabled for preconditions, then we would
+We often want to regard arithmetic in a context such as this from a
+purely mathematical point of view. So, for example, if the two actual
+parameters for a call to ``P`` are both ``Integer'Last`` then the
+precondition should be evaluated as ``False``. If we're executing in a
+mode with run-time checks enabled for preconditions, then we would
like this precondition to fail, rather than raising an exception
because of the intermediate overflow.
@@ -2759,9 +2793,9 @@ Consider the call
Q (A => Integer'Last, B => 1, C => -1);
From a mathematical point of view the precondition
-is True, but at run time we may (but are not guaranteed to) get an
+is ``True``, but at run time we may (but are not guaranteed to) get an
exception raised because of the intermediate overflow (and we really
-would prefer this precondition to be considered True at run time).
+would prefer this precondition to be considered ``True`` at run time).
.. _Management_of_Overflows_in_GNAT:
@@ -2769,11 +2803,11 @@ would prefer this precondition to be considered True at run time).
Management of Overflows in GNAT
-------------------------------
-To deal with the portability issue, and with the problem of
+To deal with the portability issue and with the problem of
mathematical versus run-time interpretation of the expressions in
assertions, GNAT provides comprehensive control over the handling
-of intermediate overflow. GNAT can operate in three modes, and
-furthermore, permits separate selection of operating modes for
+of intermediate overflows. It can operate in three modes, and
+in addition, permits separate selection of operating modes for
the expressions within assertions (here the term 'assertions'
is used in the technical sense, which includes preconditions and so forth)
and for expressions appearing outside assertions.
@@ -2785,7 +2819,7 @@ The three modes are:
In this mode, all intermediate results for predefined arithmetic
operators are computed using the base type, and the result must
be in range of the base type. If this is not the
- case then either an exception is raised (if overflow checks are
+ case, then either an exception is raised (if overflow checks are
enabled) or the execution is erroneous (if overflow checks are suppressed).
This is the normal default mode.
@@ -2806,7 +2840,7 @@ The three modes are:
improvement in space and time behavior.
However, there are cases where ``Long_Long_Integer`` is not large
- enough, consider the following example:
+ enough. Consider the following example:
.. code-block:: ada
@@ -2816,8 +2850,8 @@ The three modes are:
where ``A`` = ``B`` = ``C`` = ``D`` = ``Integer'Last``.
Now the intermediate results are
out of the range of ``Long_Long_Integer`` even though the final result
- is in range and the precondition is True (from a mathematical point
- of view). In such a case, operating in this mode, an overflow occurs
+ is in range and the precondition is ``True`` from a mathematical point
+ of view. In such a case, operating in this mode, an overflow occurs
for the intermediate computation (which is why this mode
says *most* intermediate overflows are avoided). In this case,
an exception is raised if overflow checks are enabled, and the
@@ -2830,7 +2864,7 @@ The three modes are:
mode, the above example with ``A**2 * B**2`` would
not cause intermediate overflow, because the intermediate result
would be evaluated using sufficient precision, and the result
- of evaluating the precondition would be True.
+ of evaluating the precondition would be ``True``.
This mode has the advantage of avoiding any intermediate
overflows, but at the expense of significant run-time overhead,
@@ -2840,12 +2874,12 @@ The three modes are:
This mode provides cleaner semantics for assertions, since now
the run-time behavior emulates true arithmetic behavior for the
predefined arithmetic operators, meaning that there is never a
- conflict between the mathematical view of the assertion, and its
+ conflict between the mathematical view of the assertion and its
run-time behavior.
Note that in this mode, the behavior is unaffected by whether or
not overflow checks are suppressed, since overflow does not occur.
- It is possible for gigantic intermediate expressions to raise
+ Gigantic intermediate expressions can still raise
``Storage_Error`` as a result of attempting to compute the
results of such expressions (e.g. ``Integer'Last ** Integer'Last``)
but overflow is impossible.
@@ -2855,17 +2889,17 @@ Note that these modes apply only to the evaluation of predefined
arithmetic, membership, and comparison operators for signed integer
arithmetic.
-For fixed-point arithmetic, checks can be suppressed. But if checks
-are enabled
-then fixed-point values are always checked for overflow against the
-base type for intermediate expressions (that is such checks always
+For fixed-point arithmetic, you suppress checks. But if checks
+are enabled,
+fixed-point values are always checked for overflow against the
+base type for intermediate expressions (i.e., such checks always
operate in the equivalent of ``STRICT`` mode).
For floating-point, on nearly all architectures, ``Machine_Overflows``
-is False, and IEEE infinities are generated, so overflow exceptions
-are never raised. If you want to avoid infinities, and check that
-final results of expressions are in range, then you can declare a
-constrained floating-point type, and range checks will be carried
+is ``False``, and IEEE infinities are generated, so overflow exceptions
+are never raised. If you want to avoid infinities and check that
+final results of expressions are in range, you can declare a
+constrained floating-point type and range checks are carried
out in the normal manner (with infinite values always failing all
range checks).
@@ -2877,9 +2911,10 @@ Specifying the Desired Mode
.. index:: pragma Overflow_Mode
-The desired mode of for handling intermediate overflow can be specified using
+You can specify
+the desired mode of for handling intermediate overflow using
either the ``Overflow_Mode`` pragma or an equivalent compiler switch.
-The pragma has the form
+The pragma has the form:
.. code-block:: ada
@@ -2894,9 +2929,9 @@ where ``MODE`` is one of
The case is ignored, so ``MINIMIZED``, ``Minimized`` and
``minimized`` all have the same effect.
-If only the ``General`` parameter is present, then the given ``MODE`` applies
-to expressions both within and outside assertions. If both arguments
-are present, then ``General`` applies to expressions outside assertions,
+If you only specify the ``General`` parameter, the given ``MODE`` applies
+to expressions both within and outside assertions. If you specify both arguments,
+the value of ``General`` applies to expressions outside assertions,
and ``Assertions`` applies to expressions within assertions. For example:
.. code-block:: ada
@@ -2904,18 +2939,18 @@ and ``Assertions`` applies to expressions within assertions. For example:
pragma Overflow_Mode
(General => Minimized, Assertions => Eliminated);
-specifies that general expressions outside assertions be evaluated
-in 'minimize intermediate overflows' mode, and expressions within
+specifies that expressions outside assertions be evaluated
+in 'minimize intermediate overflows' mode and expressions within
assertions be evaluated in 'eliminate intermediate overflows' mode.
This is often a reasonable choice, avoiding excessive overhead
outside assertions, but assuring a high degree of portability
-when importing code from another compiler, while incurring
+when importing code from another compiler while incurring
the extra overhead for assertion expressions to ensure that
the behavior at run time matches the expected mathematical
behavior.
The ``Overflow_Mode`` pragma has the same scoping and placement
-rules as pragma ``Suppress``, so it can occur either as a
+rules as pragma ``Suppress``, so you can use it either as a
configuration pragma, specifying a default for the whole
program, or in a declarative scope, where it applies to the
remaining declarations and statements in that scope.
@@ -2930,9 +2965,9 @@ or ``Unsuppress`` in the usual manner.
.. index:: -gnato? (gcc)
.. index:: -gnato?? (gcc)
-Additionally, a compiler switch :switch:`-gnato?` or :switch:`-gnato??`
-can be used to control the checking mode default (which can be subsequently
-overridden using pragmas).
+Additionally, you can use the compiler switch :switch:`-gnato?` or
+:switch:`-gnato??` to control the checking mode default (which you can
+subsequently override using the above pragmas).
Here ``?`` is one of the digits ``1`` through ``3``:
@@ -2942,16 +2977,15 @@ Here ``?`` is one of the digits ``1`` through ``3``:
``3`` eliminate intermediate overflows (``ELIMINATED``)
====== ======================================================
-As with the pragma, if only one digit appears then it applies to all
-cases; if two digits are given, then the first applies outside
-assertions, and the second within assertions. Thus the equivalent
+As with the pragma, if only one digit appears, it applies to all
+cases; if two digits are given, the first applies to expressions outside
+assertions and the second within assertions. Thus the equivalent
of the example pragma above would be
:switch:`-gnato23`.
-If no digits follow the :switch:`-gnato`, then it is equivalent to
-:switch:`-gnato11`,
-causing all intermediate operations to be computed using the base
-type (``STRICT`` mode).
+If you don't provide any digits following the :switch:`-gnato`, it's
+equivalent to :switch:`-gnato11`, causing all intermediate operations
+to be computed using the base type (``STRICT`` mode).
.. _Default_Settings:
@@ -2969,11 +3003,10 @@ which causes all computations both inside and outside assertions to use the
base type, and is equivalent to :switch:`-gnato` (with no digits following).
The pragma ``Suppress (Overflow_Check)`` disables overflow
-checking, but it has no effect on the method used for computing
+checking but has no effect on the method used for computing
intermediate results.
-
The pragma ``Unsuppress (Overflow_Check)`` enables overflow
-checking, but it has no effect on the method used for computing
+checking but has no effect on the method used for computing
intermediate results.
@@ -2982,15 +3015,15 @@ intermediate results.
Implementation Notes
--------------------
-In practice on typical 64-bit machines, the ``MINIMIZED`` mode is
-reasonably efficient, and can be generally used. It also helps
-to ensure compatibility with code imported from some other
-compiler to GNAT.
+In practice, on typical 64-bit machines, the ``MINIMIZED`` mode is
+reasonably efficient and you can generally use it. It also helps
+to ensure compatibility with code imported from other
+compilers to GNAT.
Setting all intermediate overflows checking (``STRICT`` mode)
makes sense if you want to
-make sure that your code is compatible with any other possible
-Ada implementation. This may be useful in ensuring portability
+make sure your code is compatible with any other
+Ada implementations. You may find this useful in ensuring portability
for code that is to be exported to some other compiler than GNAT.
The Ada standard allows the reassociation of expressions at
@@ -3022,7 +3055,7 @@ still has the same bounds as its associated constrained
type at run-time.
Currently, the ``ELIMINATED`` mode is only available on target
-platforms for which ``Long_Long_Integer`` is 64-bits (nearly all GNAT
+platforms for which ``Long_Long_Integer`` is at least 64-bits (nearly all GNAT
platforms).
@@ -3034,25 +3067,25 @@ Performing Dimensionality Analysis in GNAT
.. index:: Dimensionality analysis
-The GNAT compiler supports dimensionality checking. The user can
-specify physical units for objects, and the compiler will verify that uses
-of these objects are compatible with their dimensions, in a fashion that is
+The GNAT compiler supports dimensionality checking. You can
+specify physical units for objects and the compiler verifies that uses
+of these objects are compatible with their dimension, in a fashion that is
familiar to engineering practice. The dimensions of algebraic expressions
(including powers with static exponents) are computed from their constituents.
.. index:: Dimension_System aspect
.. index:: Dimension aspect
-This feature depends on Ada 2012 aspect specifications, and is available from
-version 7.0.1 of GNAT onwards.
+This feature depends on Ada 2012 aspect specifications and is available for
+versions 7.0.1 and later of GNAT.
The GNAT-specific aspect ``Dimension_System``
allows you to define a system of units; the aspect ``Dimension``
-then allows the user to declare dimensioned quantities within a given system.
+allows you to declare dimensioned quantities within a given system.
(These aspects are described in the *Implementation Defined Aspects*
-chapter of the *GNAT Reference Manual*).
+chapter of the :title:`GNAT Reference Manual`).
The major advantage of this model is that it does not require the declaration of
-multiple operators for all possible combinations of types: it is only necessary
+multiple operators for all possible combinations of types: you is only need
to use the proper subtypes in object declarations.
.. index:: System.Dim.Mks package (GNAT library)
@@ -3060,9 +3093,9 @@ to use the proper subtypes in object declarations.
The simplest way to impose dimensionality checking on a computation is to make
use of one of the instantiations of the package ``System.Dim.Generic_Mks``, which
-are part of the GNAT library. This generic package defines a floating-point
+is part of the GNAT library. This generic package defines a floating-point
type ``MKS_Type``, for which a sequence of dimension names are specified,
-together with their conventional abbreviations. The following should be read
+together with their conventional abbreviations. You should read the following
together with the full specification of the package, in file
:file:`s-digemk.ads`.
@@ -3122,7 +3155,7 @@ GNAT library:
* ``System.Dim.Mks`` based on ``Long_Long_Float`` defined in :file:`s-dimmks.ads`.
Using one of these packages, you can then define a derived unit by providing
-the aspect that specifies its dimensions within the MKS system, as well as the
+the aspect that specifies its dimensions within the MKS system as well as the
string to be used for output of a value of that unit:
.. code-block:: ada
@@ -3133,7 +3166,7 @@ string to be used for output of a value of that unit:
Second => -2,
others => 0);
-Here is a complete example of use:
+Here's a complete example:
.. code-block:: ada
@@ -3184,7 +3217,7 @@ are rejected with the following diagnoses:
>>> left-hand side has dimension [L]
>>> right-hand side has dimension [M]
-The dimensions of an expression are properly displayed, even if there is
+The dimensions of an expression are properly displayed even if there is
no explicit subtype for it. If we add to the program:
.. code-block:: ada
@@ -3193,7 +3226,7 @@ no explicit subtype for it. If we add to the program:
Put (G * T, Aft =>2, Exp =>0);
Put_Line ("");
-then the output includes:
+the output includes:
::
@@ -3247,7 +3280,7 @@ mathematical definitions for the vector operations that are used:
* :samp:`DV({op expr})`, where *op* is a unary operator, is :samp:`DV({expr})`
-* :samp:`DV({expr1 op expr2})` where *op* is "+" or "-" is :samp:`DV({expr1})`
+* :samp:`DV({expr1 op expr2})`, where *op* is "+" or "-", is :samp:`DV({expr1})`
provided that :samp:`DV({expr1})` = :samp:`DV({expr2})`.
If this condition is not met then the construct is illegal.
@@ -3266,7 +3299,7 @@ combine a dimensioned and dimensionless value. Thus an expression such as
``Acceleration``.
The dimensionality checks for relationals use the same rules as
-for "+" and "-", except when comparing to a literal; thus
+for "+" and "-" except when comparing to a literal; thus
.. code-block:: ada
@@ -3284,40 +3317,40 @@ and is thus illegal, but
acc > 10.0
-is accepted with a warning. Analogously a conditional expression requires the
+is accepted with a warning. Analogously, a conditional expression requires the
same dimension vector for each branch (with no exception for literals).
The dimension vector of a type conversion :samp:`T({expr})` is defined
as follows, based on the nature of ``T``:
-* If ``T`` is a dimensioned subtype then :samp:`DV(T({expr}))` is ``DV(T)``
+* If ``T`` is a dimensioned subtype, then :samp:`DV(T({expr}))` is ``DV(T)``
provided that either *expr* is dimensionless or
:samp:`DV(T)` = :samp:`DV({expr})`. The conversion is illegal
if *expr* is dimensioned and :samp:`DV({expr})` /= ``DV(T)``.
Note that vector equality does not require that the corresponding
Unit_Names be the same.
- As a consequence of the above rule, it is possible to convert between
- different dimension systems that follow the same international system
- of units, with the seven physical components given in the standard order
- (length, mass, time, etc.). Thus a length in meters can be converted to
- a length in inches (with a suitable conversion factor) but cannot be
- converted, for example, to a mass in pounds.
+ As a consequence of the above rule, you can convert between
+ different dimension systems that follow the same international
+ system of units, with the seven physical components given in the
+ standard order (length, mass, time, etc.). Thus, you can convert a
+ length in meters to a length in inches (with a suitable conversion
+ factor) but not, for example, to a mass in pounds.
* If ``T`` is the base type for *expr* (and the dimensionless root type of
the dimension system), then :samp:`DV(T({expr}))` is ``DV(expr)``.
Thus, if *expr* is of a dimensioned subtype of ``T``, the conversion may
be regarded as a "view conversion" that preserves dimensionality.
- This rule makes it possible to write generic code that can be instantiated
- with compatible dimensioned subtypes. The generic unit will contain
+ This rule means you can write generic code that can be instantiated
+ with compatible dimensioned subtypes. You include in the generic unit
conversions that will consequently be present in instantiations, but
conversions to the base type will preserve dimensionality and make it
possible to write generic code that is correct with respect to
dimensionality.
* Otherwise (i.e., ``T`` is neither a dimensioned subtype nor a dimensionable
- base type), :samp:`DV(T({expr}))` is the empty vector. Thus a dimensioned
+ base type), :samp:`DV(T({expr}))` is the empty vector. Thus, a dimensioned
value can be explicitly converted to a non-dimensioned subtype, which
of course then escapes dimensionality analysis.
@@ -3330,14 +3363,14 @@ An assignment statement
Source := Target;
-requires ``DV(Source)`` = ``DV(Target)``, and analogously for parameter
+requires ``DV(Source)`` = ``DV(Target)`` and analogously for parameter
passing (the dimension vector for the actual parameter must be equal to the
dimension vector for the formal parameter).
-When using dimensioned types with elementary functions it is necessary to
+When using dimensioned types with elementary functions, you need not
instantiate the ``Ada.Numerics.Generic_Elementary_Functions`` package using
-the ``Mks_Type`` and not any of the derived subtypes such as ``Distance``.
-For functions such as ``Sqrt`` the dimensional analysis will fail when using
+the ``Mks_Type`` nor for any of the derived subtypes such as ``Distance``.
+For functions such as ``Sqrt``, the dimensional analysis will fail when using
the subtypes because both the parameter and return are of the same type.
An example instantiation
@@ -3367,7 +3400,7 @@ Stack Overflow Checking
For most operating systems, ``gcc`` does not perform stack overflow
checking by default. This means that if the main environment task or
-some other task exceeds the available stack space, then unpredictable
+some other task exceeds the available stack space, unpredictable
behavior will occur. Most native systems offer some level of protection by
adding a guard page at the end of each task stack. This mechanism is usually
not enough for dealing properly with stack overflow situations because
@@ -3377,7 +3410,7 @@ guard page is hit, there may not be any space left on the stack for executing
the exception propagation code. Enabling stack checking avoids
such situations.
-To activate stack checking, compile all units with the ``gcc`` option
+To activate stack checking, compile all units with the ``gcc`` switch
:switch:`-fstack-check`. For example:
::
@@ -3387,17 +3420,19 @@ To activate stack checking, compile all units with the ``gcc`` option
Units compiled with this option will generate extra instructions to check
that any use of the stack (for procedure calls or for declaring local
variables in declare blocks) does not exceed the available stack space.
-If the space is exceeded, then a ``Storage_Error`` exception is raised.
+If the space is exceeded, a ``Storage_Error`` exception is raised.
For declared tasks, the default stack size is defined by the GNAT runtime,
whose size may be modified at bind time through the ``-d`` bind switch
-(:ref:`Switches_for_gnatbind`). Task specific stack sizes may be set using the
+(:ref:`Switches_for_gnatbind`). You can set task specific stack sizes using the
``Storage_Size`` pragma.
For the environment task, the stack size is determined by the operating system.
Consequently, to modify the size of the environment task please refer to your
operating system documentation.
+When using the LLVM backend, this switch doesn't perform full stack overflow
+checking, but just checks for very large local dynamic allocations.
.. _Static_Stack_Usage_Analysis:
@@ -3408,9 +3443,9 @@ Static Stack Usage Analysis
.. index:: -fstack-usage
-A unit compiled with ``-fstack-usage`` will generate an extra file
+A unit compiled with the :switch:`-fstack-usage` switch generate an extra file
that specifies
-the maximum amount of stack used, on a per-function basis.
+the maximum amount of stack used on a per-function basis.
The file has the same
basename as the target object file with a :file:`.su` extension.
Each line of this file is made up of three fields:
@@ -3435,9 +3470,12 @@ of the function stack analysis. When it is qualified with ``bounded``, it
means that the second field is a reliable maximum of the function stack
utilization.
-A unit compiled with ``-Wstack-usage`` will issue a warning for each
-subprogram whose stack usage might be larger than the specified amount of
-bytes. The wording is in keeping with the qualifier documented above.
+Compilation of a unit with the :switch:`-Wstack-usage` switch will
+issue a warning for each subprogram whose stack usage might be larger
+than the specified amount of bytes. The wording of that warning is
+consistent with that in the file documented above.
+
+This is not supported by the LLVM backend.
.. _Dynamic_Stack_Usage_Analysis:
@@ -3445,7 +3483,7 @@ bytes. The wording is in keeping with the qualifier documented above.
Dynamic Stack Usage Analysis
----------------------------
-It is possible to measure the maximum amount of stack used by a task, by
+You can measure the maximum amount of stack used by a task by
adding a switch to ``gnatbind``, as:
::
@@ -3458,16 +3496,16 @@ Note that this switch is not compatible with tools like
Valgrind and DrMemory; they will report errors.
It is not always convenient to output the stack usage when the program
-is still running. Hence, it is possible to delay this output until program
-termination. for a given number of tasks specified as the argument of the
-``-u`` option. For instance:
+is still running. Hence, you can delay this output until the
+termination of the number of tasks specified as the argument of the
+:switch:`-u` switch. For example:
::
$ gnatbind -u100 file
-will buffer the stack usage information of the first 100 tasks to terminate and
-output this info at program termination. Results are displayed in four
+buffers the stack usage information of the first 100 tasks to terminate and
+outputs it when the program terminates. Results are displayed in four
columns:
::
@@ -3487,10 +3525,11 @@ where:
is not entirely analyzed, and it's not possible to know exactly how
much has actually been used.
-By default the environment task stack, the stack that contains the main unit,
-is not processed. To enable processing of the environment task stack, the
-environment variable GNAT_STACK_LIMIT needs to be set to the maximum size of
-the environment task stack. This amount is given in kilobytes. For example:
+By default, ``gnatbind`` does not process the environment task stack,
+the stack that contains the main unit. To enable processing of the
+environment task stack, set the environment variable GNAT_STACK_LIMIT
+to the maximum size of the environment task stack. This amount is
+given in kilobytes. For example:
::
@@ -3499,6 +3538,8 @@ the environment task stack. This amount is given in kilobytes. For example:
would specify to the analyzer that the environment task stack has a limit
of 1.6 megabytes. Any stack usage beyond this will be ignored by the analysis.
+This is not suppored by the LLVM backend.
+
The package ``GNAT.Task_Stack_Usage`` provides facilities to get
stack-usage reports at run time. See its body for the details.
@@ -3509,7 +3550,7 @@ stack-usage reports at run time. See its body for the details.
Memory Management Issues
========================
-This section describes some useful memory pools provided in the GNAT library
+This section describes some useful memory pools provided in the GNAT library,
and in particular the GNAT Debug Pool facility, which can be used to detect
incorrect uses of access values (including 'dangling references').
@@ -3526,14 +3567,14 @@ Some Useful Memory Pools
.. index:: Memory Pool
.. index:: storage, pool
-The ``System.Pool_Global`` package offers the Unbounded_No_Reclaim_Pool
+The ``System.Pool_Global`` package provides the ``Unbounded_No_Reclaim_Pool``
storage pool. Allocations use the standard system call ``malloc`` while
deallocations use the standard system call ``free``. No reclamation is
performed when the pool goes out of scope. For performance reasons, the
standard default Ada allocators/deallocators do not use any explicit storage
pools but if they did, they could use this storage pool without any change in
behavior. That is why this storage pool is used when the user
-manages to make the default implicit allocator explicit as in this example:
+makes the default implicit allocator explicit as in this example:
.. code-block:: ada
@@ -3545,8 +3586,8 @@ manages to make the default implicit allocator explicit as in this example:
-- the above is equivalent to
for T2'Storage_Pool use System.Pool_Global.Global_Pool_Object;
-The ``System.Pool_Local`` package offers the ``Unbounded_Reclaim_Pool`` storage
-pool. The allocation strategy is similar to ``Pool_Local``
+The ``System.Pool_Local`` package provides the ``Unbounded_Reclaim_Pool`` storage
+pool. Its allocation strategy is similar to ``Pool_Local``
except that the all
storage allocated with this pool is reclaimed when the pool object goes out of
scope. This pool provides a explicit mechanism similar to the implicit one
@@ -3581,7 +3622,8 @@ The whole storage for the pool is
allocated at once, usually on the stack at the point where the access type is
elaborated. It is automatically reclaimed when exiting the scope where the
access type is defined. This package is not intended to be used directly by the
-user and it is implicitly used for each such declaration:
+user; it is implicitly used for each declaration with a specified
+``Storage_Size``:
.. code-block:: ada
@@ -3597,14 +3639,14 @@ The GNAT Debug Pool Facility
.. index:: Debug Pool
.. index:: storage, pool, memory corruption
-The use of unchecked deallocation and unchecked conversion can easily
+Using unchecked deallocation and unchecked conversion can easily
lead to incorrect memory references. The problems generated by such
-references are usually difficult to tackle because the symptoms can be
+references are usually difficult to find because the symptoms can be
very remote from the origin of the problem. In such cases, it is
very helpful to detect the problem as early as possible. This is the
purpose of the Storage Pool provided by ``GNAT.Debug_Pools``.
-In order to use the GNAT specific debugging pool, the user must
+In order to use the GNAT specific debugging pool, you must
associate a debug pool object with each of the access types that may be
related to suspected memory problems. See Ada Reference Manual 13.11.
@@ -3616,12 +3658,12 @@ related to suspected memory problems. See Ada Reference Manual 13.11.
``GNAT.Debug_Pools`` is derived from a GNAT-specific kind of
pool: the ``Checked_Pool``. Such pools, like standard Ada storage pools,
-allow the user to redefine allocation and deallocation strategies. They
-also provide a checkpoint for each dereference, through the use of
+allow you to redefine allocation and deallocation strategies. They
+also provide a checkpoint for each dereference through the use of
the primitive operation ``Dereference`` which is implicitly called at
each dereference of an access value.
-Once an access type has been associated with a debug pool, operations on
+Once you have associated an access type with a debug pool, operations on
values of the type may raise four distinct exceptions,
which correspond to four potential kinds of memory corruption:
@@ -3633,17 +3675,17 @@ which correspond to four potential kinds of memory corruption:
For types associated with a Debug_Pool, dynamic allocation is performed using
the standard GNAT allocation routine. References to all allocated chunks of
memory are kept in an internal dictionary. Several deallocation strategies are
-provided, whereupon the user can choose to release the memory to the system,
+provided, allowing you to choose to release the memory to the system,
keep it allocated for further invalid access checks, or fill it with an easily
recognizable pattern for debug sessions. The memory pattern is the old IBM
hexadecimal convention: ``16#DEADBEEF#``.
-See the documentation in the file g-debpoo.ads for more information on the
-various strategies.
+See the documentation in the file :file:`g-debpoo.ads` for more
+information on the various strategies.
Upon each dereference, a check is made that the access value denotes a
-properly allocated memory location. Here is a complete example of use of
-``Debug_Pools``, that includes typical instances of memory corruption:
+properly allocated memory location. Here's a complete example of use of
+``Debug_Pools``, which includes typical instances of memory corruption:
.. code-block:: ada
@@ -3737,8 +3779,8 @@ execution of this erroneous program:
The ``gnatmem`` utility monitors dynamic allocation and
deallocation activity in a program, and displays information about
incorrect deallocations and possible sources of memory leaks.
- It is designed to work for fixed-position executables in association
- with a static runtime library only and in this context provides three
+ It is designed to work for fixed-position executables that use
+ a static runtime library and, in this context, provides three
types of information:
* General information concerning memory management, such as the total
@@ -3746,8 +3788,8 @@ execution of this erroneous program:
memory and the high water mark, i.e., the largest amount of allocated
memory in the course of program execution.
- * Backtraces for all incorrect deallocations, that is to say deallocations
- which do not correspond to a valid allocation.
+ * Backtraces for all incorrect deallocations, which are deallocations
+ that do not correspond to a valid allocation.
* Information on each allocation that is potentially the origin of a memory
leak.
@@ -3769,36 +3811,36 @@ execution of this erroneous program:
$ gnatmem [ switches ] [ DEPTH ] user_program
- The user program must be linked with the instrumented version of the
- allocation and deallocation routines. This is done by linking with the
+ You must link your program with the instrumented version of the
+ allocation and deallocation routines. You do this by linking with the
:file:`libgmem.a` library. For correct symbolic backtrace information,
- the user program should also both be compiled with debugging options
- (see :ref:`Switches_for_gcc`) and be linked at a fixed position with
- :switch:`-no-pie`. For example to build :file:`my_program` with
+ you should also compile your program with debugging options
+ (see :ref:`Switches_for_gcc`) and be linked at a fixed position (with
+ :switch:`-no-pie`). For example to build :file:`my_program` with
``gnatmake``:
::
$ gnatmake my_program -g -largs -lgmem -no-pie
- As library :file:`libgmem.a` contains an alternate body for package
- ``System.Memory``, :file:`s-memory.adb` should not be compiled and linked
- when an executable is linked with library :file:`libgmem.a`. It is then not
- recommended to use ``gnatmake`` with switch :switch:`-a`.
+ Because library :file:`libgmem.a` contains an alternate body for package
+ ``System.Memory``, you should not compile and link :file:`s-memory.adb`
+ when you link an executable with library :file:`libgmem.a`. In that case,
+ we don't recommended specifying switch :switch:`-a` to ``gnatmake``.
When :file:`my_program` is executed, the file :file:`gmem.out` is produced.
This file contains information about all allocations and deallocations
performed by the program. It is produced by the instrumented allocations and
deallocations routines and will be used by ``gnatmem``.
- In order to produce symbolic backtrace information for allocations and
+ To produce symbolic backtrace information for allocations and
deallocations performed by the GNAT run-time library, you need to use a
version of that library that has been compiled with the :switch:`-g` switch
(see :ref:`Rebuilding_the_GNAT_Run-Time_Library`).
- ``gnatmem`` must be supplied with the :file:`gmem.out` file and the executable to
+ You must supply ``gnatmem`` with the :file:`gmem.out` file and the executable to
examine. If the location of :file:`gmem.out` file was not explicitly supplied by
- :switch:`-i` switch, gnatmem will assume that this file can be found in the
+ :switch:`-i` switch, ``gnatmem`` assumes that this file can be found in the
current directory. For example, after you have executed :file:`my_program`,
:file:`gmem.out` can be analyzed by ``gnatmem`` using the command:
@@ -3834,14 +3876,14 @@ execution of this erroneous program:
.
The first block of output gives general information. In this case, the
- Ada construct ``new`` was executed 45 times, and only 6 calls to an
- Unchecked_Deallocation routine occurred.
+ Ada construct ``new`` was executed 45 times and only 6 calls to an
+ ``Unchecked_Deallocation`` routine occurred.
- Subsequent paragraphs display information on all allocation roots.
- An allocation root is a specific point in the execution of the program
+ Subsequent paragraphs display information on all allocation roots.
+ An *allocation root* is a specific point in the execution of the program
that generates some dynamic allocation, such as a ``new``
construct. This root is represented by an execution backtrace (or subprogram
- call stack). By default the backtrace depth for allocations roots is 1, so
+ call stack). By default, the backtrace depth for allocations roots is 1, so
that a root corresponds exactly to a source location. The backtrace can
be made deeper, to make the root more specific.
@@ -3854,59 +3896,60 @@ execution of this erroneous program:
.. index:: -q (gnatmem)
- :samp:`-q`
+ :switch:`-q`
Quiet. Gives the minimum output needed to identify the origin of the
memory leaks. Omits statistical information.
.. index:: DEPTH switch (gnatmem)
- :samp:`{DEPTH}`
+ :switch:`{DEPTH}`
``DEPTH`` is an integer literal (usually between 1 and 10) which controls
the depth of the backtraces defining allocation root. The default value for
DEPTH is 1. The deeper the backtrace, the more precise the localization of
the root. Note that the total number of roots can depend on this
- parameter, in other words there may be more roots when the requested
- backtrace depth is higher. This parameter must be specified *before* the
+ parameter; in other words there may be more roots when the requested
+ backtrace depth is higher. You must specify this parameter *before* the
name of the executable to be analyzed, to avoid ambiguity.
.. index:: -b (gnatmem)
- :samp:`-b {N}`
+ :switch:`-b {N}`
This switch has the same effect as just a depth parameter ``N``.
.. index:: -i (gnatmem)
- :samp:`-i {file}`
+ :switch:`-i {file}`
Do the ``gnatmem`` processing starting from :file:`file`, rather than
:file:`gmem.out` in the current directory.
.. index:: -m (gnatmem)
- :samp:`-m {n}`
+ :switch:`-m {n}`
This switch causes ``gnatmem`` to mask the allocation roots that have less
- than n leaks. The default value is 1. Specifying the value of 0 will allow
+ than ``n`` leaks. The default value is 1. Specifying the value of 0 will allow
examination of even the roots that did not result in leaks.
.. index:: -s (gnatmem)
- :samp:`-s {order}`
- This switch causes ``gnatmem`` to sort the allocation roots according to the
- specified order of sort criteria, each identified by a single letter. The
- currently supported criteria are ``n``, ``h``, and ``w`` standing respectively for
- number of unfreed allocations, high watermark, and final watermark
- corresponding to a specific root. The default order is ``nwh``.
+ :switch:`-s {order}`
+ This switch causes ``gnatmem`` to sort the allocation roots
+ according to the specified sort criteria, each identified by a
+ single letter. The currently supported criteria are ``n``, ``h``,
+ and ``w`` representing, respectively, the number of unfreed
+ allocations, the high watermark, and the final watermark corresponding to
+ a specific root. The default order is ``nwh``.
.. index:: -t (gnatmem)
- :samp:`-t`
+ :switch:`-t`
This switch causes memory allocated size to be always output in bytes.
- Default ``gnatmem`` behavior is to show memory sizes less then 1 kilobyte
+ The default ``gnatmem`` behavior is to show memory sizes less then 1 kilobyte
in bytes, from 1 kilobyte till 1 megabyte in kilobytes and the rest in
megabytes.
@@ -3958,19 +4001,20 @@ execution of this erroneous program:
$ gnatmake -g test_gm -largs -lgmem
- Then we execute the program as usual:
+ We execute the program as usual:
::
$ test_gm
- Then ``gnatmem`` is invoked simply with
+ ``gnatmem`` is invoked simply with
::
$ gnatmem test_gm
- which produces the following output (result may vary on different platforms):
+ which produces the following output (the details may vary on
+ different platforms):
::
@@ -4006,23 +4050,23 @@ execution of this erroneous program:
s-secsta.adb:181 system.secondary_stack.ss_init
- Note that the GNAT runtime contains itself a certain number of
- allocations that have no corresponding deallocation,
+ Note that the GNAT runtime itself contains a certain number of
+ allocations that have no corresponding deallocations,
as shown here for root #2 and root #3.
This is a normal behavior when the number of non-freed allocations
- is one, it allocates dynamic data structures that the run time needs for
+ is one: it allocates dynamic data structures that the run time needs for
the complete lifetime of the program. Note also that there is only one
- allocation root in the user program with a single line back trace:
- test_gm.adb:11 test_gm.my_alloc, whereas a careful analysis of the
- program shows that 'My_Alloc' is called at 2 different points in the
+ allocation root in the user program, with a single line back trace:
+ ``test_gm.adb:11 test_gm.my_alloc``, whereas a careful analysis of the
+ program shows that ``My_Alloc`` is called at 2 different points in the
source (line 21 and line 24). If those two allocation roots need to be
- distinguished, the backtrace depth parameter can be used:
+ distinguished, you can use the backtrace depth parameter:
::
$ gnatmem 3 test_gm
- which will give the following output:
+ which produces the following output:
::
@@ -18,7 +18,7 @@ This chapter describes a number of utility programs:
* :ref:`The_Body_Stub_Generator_gnatstub`
* :ref:`The_Backtrace_Symbolizer_gnatsymbolize`
- It also describes how several of these tools can be used in conjunction
+ It also describes how you can use several of these tools in conjunction
with project files: :ref:`Using_Project_Files_with_GNAT_Tools`
.. only:: FSF
@@ -42,7 +42,7 @@ The File Cleanup Utility ``gnatclean``
.. index:: File cleanup tool
.. index:: gnatclean
-``gnatclean`` is a tool that allows the deletion of files produced by the
+``gnatclean`` is a tool that deletes some files produced by the
compiler, binder and linker, including ALI files, object files, tree files,
expanded source files, library files, interface copy source files, binder
generated files and executable files.
@@ -52,21 +52,21 @@ generated files and executable files.
Running ``gnatclean``
---------------------
-The ``gnatclean`` command has the form:
+You run the ``gnatclean`` command as follow:
::
$ gnatclean switches names
-where ``names`` is a list of source file names. Suffixes :file:`.ads` and
-:file:`adb` may be omitted. If a project file is specified using switch
-:switch:`-P`, then ``names`` may be completely omitted.
+where ``names`` is a list of source file names. You may omit suffixes :file:`.ads` and
+:file:`adb`. If a project file is specified using switch
+:switch:`-P`, then you may completely omit ``names``.
-In normal mode, ``gnatclean`` delete the files produced by the compiler and,
-if switch :switch:`-c` is not specified, by the binder and
-the linker. In informative-only mode, specified by switch
-:switch:`-n`, the list of files that would have been deleted in
-normal mode is listed, but no file is actually deleted.
+In normal mode, ``gnatclean`` deletes the files produced by the compiler and,
+if switch :switch:`-c` is not specified, produced by the binder and
+linker. In information-only mode, specified by switch
+:switch:`-n`, ``gnatclean`` lists the files that would have been deleted in
+normal mode, but doesn't actually delete any files.
.. _Switches_for_gnatclean:
@@ -79,22 +79,22 @@ Switches for ``gnatclean``
.. index:: --version (gnatclean)
:switch:`--version`
- Display copyright and version, then exit disregarding all other options.
+ Display copyright and version, then exit, disregarding all other options.
.. index:: --help (gnatclean)
:switch:`--help`
- If :switch:`--version` was not used, display usage, then exit disregarding
- all other options.
+ If :switch:`--version` was not specified, display usage, then exit
+ disregarding all other options.
:switch:`--subdirs={subdir}`
- Actual object directory of each project file is the subdirectory subdir of the
- object directory specified or defaulted in the project file.
+ Actual object directory of each project file, which is the
+ subdirectory ``subdir`` of the object directory specified or defaulted
+ in the project file.
:switch:`--unchecked-shared-lib-imports`
By default, shared library projects are not allowed to import static library
- projects. When this switch is used on the command line, this restriction is
- relaxed.
+ projects. When this switch is specified, this restriction is lifted.
.. index:: -c (gnatclean)
@@ -106,15 +106,16 @@ Switches for ``gnatclean``
.. index:: -D (gnatclean)
:switch:`-D {dir}`
- Indicate that ALI and object files should normally be found in directory ``dir``.
+ Indicate that ALI and object files should normally be found in
+ directory ``dir``.
.. index:: -F (gnatclean)
:switch:`-F`
- When using project files, if some errors or warnings are detected during
- parsing and verbose mode is not in effect (no use of switch
- -v), then error lines start with the full path name of the project
- file, rather than its simple file name.
+ When using project files, if some errors or warnings are detected
+ during parsing and verbose mode is not in effect (the switch
+ :switch:`-v` is not specified), error lines start with the full path
+ name of the project file, rather than its simple file name.
.. index:: -h (gnatclean)
@@ -130,26 +131,27 @@ Switches for ``gnatclean``
.. index:: -P (gnatclean)
:switch:`-P{project}`
- Use project file ``project``. Only one such switch can be used.
- When cleaning a project file, the files produced by the compilation of the
- immediate sources or inherited sources of the project files are to be
- deleted. This is not depending on the presence or not of executable names
- on the command line.
+ Use project file ``project``. You can specify only one such switch.
+ When cleaning a project file, ``gnatclean`` deletes the files
+ produced by the compilation of the immediate sources or inherited
+ sources of the project files. This does not depend on whether or not
+ you include executable names on the command line.
.. index:: -q (gnatclean)
:switch:`-q`
Quiet output. If there are no errors, do not output anything, except in
- verbose mode (switch -v) or in informative-only mode
- (switch -n).
+ verbose mode (:switch:`-v`) or in information-only mode
+ (:switch:`-n`).
.. index:: -r (gnatclean)
:switch:`-r`
- When a project file is specified (using switch -P),
- clean all imported and extended project files, recursively. If this switch
- is not specified, only the files related to the main project file are to be
- deleted. This switch has no effect if no project file is specified.
+ When a project file is specified (using :switch:`-P`), clean all
+ imported and extended project files, recursively. If you don't
+ specify this switch, ``gnatclean`` only deletes the files related to
+ the main project file. This switch has no effect if you don't
+ specify a project file.
.. index:: -v (gnatclean)
@@ -200,7 +202,7 @@ The GNAT Library Browser ``gnatls``
``gnatls`` is a tool that outputs information about compiled
units. It gives the relationship between objects, unit names and source
-files. It can also be used to check the source dependencies of a unit
+files. You can also use it to check the source dependencies of a unit
as well as various characteristics.
.. _Running_gnatls:
@@ -208,7 +210,7 @@ as well as various characteristics.
Running ``gnatls``
------------------
-The ``gnatls`` command has the form
+You run the ``gnatls`` command as follows:
::
@@ -216,15 +218,15 @@ The ``gnatls`` command has the form
The main argument is the list of object or :file:`ali` files
(see :ref:`The_Ada_Library_Information_Files`)
-for which information is requested.
+for which you are requesting information.
-In normal mode, without additional option, ``gnatls`` produces a
-four-column listing. Each line represents information for a specific
+In the default mode, without additional options, ``gnatls`` produces a
+four-column listing. Each line contains information for a specific
object. The first column gives the full path of the object, the second
-column gives the name of the principal unit in this object, the third
+column gives the name of the principal unit in the object, the third
column gives the status of the source and the fourth column gives the
full path of the source representing this unit.
-Here is a simple example of use:
+Here's a simple example:
::
@@ -239,9 +241,9 @@ Here is a simple example of use:
./text_io_example.o text_io_example OK text_io_example.adb
./tgef.o tgef DIF tgef.adb
-The first line can be interpreted as follows: the main unit which is
+You should interpret the first line as follows: the main unit, which is
contained in
-object file :file:`demo1.o` is demo1, whose main source is in
+object file :file:`demo1.o`, is demo1, whose main source is in
:file:`demo1.adb`. Furthermore, the version of the source used for the
compilation of demo1 has been modified (DIF). Each source file has a status
qualifier which can be:
@@ -253,9 +255,9 @@ qualifier which can be:
*MOK (slightly modified)*
The version of the source file used for the compilation of the
specified unit differs from the actual source file but not enough to
- require recompilation. If you use gnatmake with the option
- :switch:`-m` (minimal recompilation), a file marked
- MOK will not be recompiled.
+ require recompilation (e.g., only comments have been changed). If
+ you run ``gnatmake`` with the option :switch:`-m` (minimal
+ recompilation), it will not recompile a file marked MOK.
*DIF (modified)*
No version of the source found on the path corresponds to the source
@@ -275,20 +277,20 @@ qualifier which can be:
Switches for ``gnatls``
-----------------------
-``gnatls`` recognizes the following switches:
+You can specify the following switches to ``gnatls``:
.. index:: --version (gnatls)
:switch:`--version`
- Display copyright and version, then exit disregarding all other options.
+ Display copyright and version, then exit, disregarding all other options.
.. index:: --help (gnatls)
:switch:`--help`
- If :switch:`--version` was not used, display usage, then exit disregarding
- all other options.
+ If :switch:`--version` was not specified, display usage, then exit,
+ disregarding all other options.
.. index:: -a (gnatls)
@@ -301,7 +303,7 @@ Switches for ``gnatls``
.. index:: -d (gnatls)
:switch:`-d`
- List sources from which specified units depend on.
+ List sources that specified units depend on.
.. index:: -h (gnatls)
@@ -331,10 +333,10 @@ Switches for ``gnatls``
.. index:: -files (gnatls)
:switch:`-files={file}`
- Take as arguments the files listed in text file ``file``.
- Text file ``file`` may contain empty lines that are ignored.
- Each nonempty line should contain the name of an existing file.
- Several such switches may be specified simultaneously.
+ Take as arguments the files listed in text file ``file``, which may
+ contain empty lines that are ignored. Each nonempty line should
+ contain the name of an existing file. Several such switches may be
+ specified on the same command.
.. index:: -aO (gnatls)
@@ -346,8 +348,8 @@ Switches for ``gnatls``
.. index:: -I- (gnatls)
:switch:`-aO{dir}`, :switch:`-aI{dir}`, :switch:`-I{dir}`, :switch:`-I-`, :switch:`-nostdinc`
- Source path manipulation. Same meaning as the equivalent ``gnatmake``
- flags (:ref:`Switches_for_gnatmake`).
+ Source path manipulation. It has the same meaning as the equivalent
+ ``gnatmake`` switches (:ref:`Switches_for_gnatmake`).
.. index:: -aP (gnatls)
@@ -359,14 +361,15 @@ Switches for ``gnatls``
.. index:: --RTS (gnatls)
:switch:`--RTS={rts-path}`
- Specifies the default location of the runtime library. Same meaning as the
- equivalent ``gnatmake`` flag (:ref:`Switches_for_gnatmake`).
+ Specifies the default location of the runtime library. It has the
+ same meaning as the equivalent ``gnatmake`` switch
+ (:ref:`Switches_for_gnatmake`).
.. index:: -v (gnatls)
:switch:`-v`
- Verbose mode. Output the complete source, object and project paths. Do not use
+ Verbose mode. Output the complete source, object and project paths. Don't use
the default column layout but instead use long format giving as much as
information possible on each requested units, including special
characteristics such as:
@@ -394,8 +397,8 @@ Switches for ``gnatls``
Example of ``gnatls`` Usage
---------------------------
-Example of using the verbose switch. Note how the source and
-object paths are affected by the -I switch.
+Here's an example of using the verbose switch. Note how the source and
+object paths are affected by the :switch:`-I` switch.
::
@@ -425,9 +428,9 @@ object paths are affected by the -I switch.
Flags => No_Elab_Code
Source => demo1.adb modified
-The following is an example of use of the dependency list.
-Note the use of the -s switch
-which gives a straight list of source files. This can be useful for
+Here's an example of use of the dependency list.
+Note the use of the :switch:`-s` switch,
+which gives a simple list of source files. You may find this useful for
building specialized scripts.
::
@@ -505,7 +508,7 @@ building specialized scripts.
file name may contain path information; it does not have to follow
the GNAT file naming rules
- Note that it is no longer necessary to specify the Ada language version;
+ Note that you no longer need to specify the Ada language version;
``gnatpp`` can process Ada source code written in any version from Ada 83
onward without specifying any language version switch.
@@ -518,7 +521,7 @@ building specialized scripts.
The following subsections describe the various switches accepted by
``gnatpp``, organized by category.
- You specify a switch by supplying a name and generally also a value.
+ You specify a switch by supplying a name and usually also a value.
In many cases the values for a switch with a given name are incompatible
with each other
(for example the switch that controls the casing of a reserved word may have
@@ -527,7 +530,7 @@ building specialized scripts.
invocation of ``gnatpp``.
If more than one is supplied, the last one is used.
However, some values for the same switch are mutually compatible.
- You may supply several such switches to ``gnatpp``, but then
+ You may supply several such switches to ``gnatpp``, but
each must be specified in full, with both the name and the value.
Abbreviated forms (the name appearing once, followed by each value) are
not permitted.
@@ -548,10 +551,10 @@ building specialized scripts.
:switch:`--layout=default|minimal|compact|tall`
:switch:`default`
- The default layout will follow a compact style but add aligment and put
- some keywords on a separate line.
+ The default layout is a compact style, but ``gnatpp`` adds
+ alignment and puts some keywords on a separate line.
- Alignment is added in the the following constructs:
+ ``gnatpp`` adds alignment in the the following constructs:
* ``:`` in declarations,
* ``:=`` in initializations in declarations,
@@ -560,14 +563,14 @@ building specialized scripts.
* ``at`` keywords in the component clauses in record representation
clauses.
- In addition, ``in`` and ``out`` keywords in parameter specifications are
- also lined up.
+ In addition, ``gnatpp`` also lines up ``in`` and ``out`` keywords
+ in parameter specifications.
- The keyword ``is`` is placed on a separate line in a subprogram body in
- case the spec occupies more than one line.
+ ``gnatpp`` places the keyword ``is`` on a separate line in a
+ subprogram body in case the spec occupies more than one line.
- The keyword ``return`` is placed on a separate line if a subprogram spec
- does not fit on one line.
+ ``gnatpp`` places the keyword ``return`` on a separate line if a
+ subprogram spec does not fit on one line.
:switch:`minimal`
The minimal layout will avoid changing the source layout by keeping all
@@ -576,10 +579,10 @@ building specialized scripts.
the line length limit.
:switch:`compact`
- The compact layout will avoid adding line breaks and alignment by packing
+ The compact layout avoids adding line breaks and alignment by packing
as many subexpressions on the same line as possible.
- Whole-line comments that form a paragraph will be filled in typical word
+ Whole-line comments that form a paragraph are filled in typical word
processor style (that is, moving words between lines to make them similar
in length, except the last one which may be shorter).
@@ -589,7 +592,7 @@ building specialized scripts.
comment.
:switch:`tall`
- The tall layout will favor adding lines breaks and alignment. It adds
+ The tall layout favors adding lines breaks and alignment. It adds
all the alignment and line breaks defined in the ``default`` option,
and in addition:
@@ -628,17 +631,21 @@ building specialized scripts.
.. index:: Casing control in gnatpp
- ``gnatpp`` allows you to specify the casing for reserved words, pragma
- names, attribute designators and identifiers. For identifiers you may define
- a general rule for name casing but also override this rule via a set of
- dictionary files.
+ ``gnatpp`` allows you to specify the casing for reserved words,
+ pragma names, attribute designators, and identifiers. For
+ identifiers, you may define a general rule for name casing but also
+ override this rule via a set of dictionary files.
Three types of casing are supported: 'Lower Case', 'Upper Case', and
- 'Mixed Case'. 'Mixed case' means that the first letter, and also each
- letter immediately following an underscore, are converted to their
- uppercase forms and all the other letters are converted to their lowercase
+ 'Mixed Case'. 'Mixed case' means that the first letter and each
+ letter immediately following an underscore are converted to their
+ uppercase forms and all other letters are converted to their lowercase
forms.
+
+
+
+
.. index:: --name-case-as-declared (gnatpp)
:switch:`--name-case-as-declared, -nD`
@@ -690,24 +697,24 @@ building specialized scripts.
:switch:`--enum-case-as-declared, -neD`
Enumeration literal casing for defining occurrences are as they appear in
- the source file. Overrides -n casing setting.
+ the source file. Overrides the :switch:`-n` casing setting.
.. index:: --enum-upper-case (gnatpp)
:switch:`--enum-upper-case, -neU`
- Enumeration literals are in upper case. Overrides -n casing
+ Enumeration literals are in upper case. Overrides the :switch:`-n` casing
setting.
.. index:: --enum-lower-case (gnatpp)
:switch:`--enum-lower-case, -neL`
- Enumeration literals are in lower case. Overrides -n casing
+ Enumeration literals are in lower case. Overrides the :switch:`-n` casing
setting.
.. index:: --enum-mixed-case (gnatpp)
:switch:`--enum-mixed-case, -neM`
- Enumeration literals are in mixed case. Overrides -n casing
+ Enumeration literals are in mixed case. Overrides the :switch:`-n` casing
setting.
.. index:: --type-case-as-declared (gnatpp)
@@ -715,37 +722,37 @@ building specialized scripts.
:switch:`--type-case-as-declared, -ntD`
Names introduced by type and subtype declarations are always
cased as they appear in the declaration in the source file.
- Overrides -n casing setting.
+ Overrides the :switch:`-n` casing setting.
.. index:: --type-upper-case (gnatpp)
:switch:`--type-upper-case, -ntU`
Names introduced by type and subtype declarations are always in
- upper case. Overrides -n casing setting.
+ upper case. Overrides the :switch:`-n` casing setting.
.. index:: --type-lower-case (gnatpp)
:switch:`--type-lower-case, -ntL`
Names introduced by type and subtype declarations are always in
- lower case. Overrides -n casing setting.
+ lower case. Overrides the :switch:`-n` casing setting.
.. index:: --type-mixed-case (gnatpp)
:switch:`--type-mixed-case, -ntM`
Names introduced by type and subtype declarations are always in
- mixed case. Overrides -n casing setting.
+ mixed case. Overrides the :switch:`-n` casing setting.
.. index:: --number-upper-case (gnatpp)
:switch:`--number-upper-case, -nnU`
Names introduced by number declarations are always in
- upper case. Overrides -n casing setting.
+ upper case. Overrides the :switch:`-n` casing setting.
.. index:: --number-lower-case (gnatpp)
:switch:`--number-lower-case, -nnL`
Names introduced by number declarations are always in
- lower case. Overrides -n casing setting.
+ lower case. Overrides the :switch:`-n` casing setting.
.. index:: --number-mixed-case (gnatpp)
@@ -798,7 +805,7 @@ building specialized scripts.
:switch:`--syntax-only`
Disable the semantic analysis (name resolution) done by libadalang.
- This means gnatpp will not be able to support any of the
+ This means ``gnatpp`` is not able to support any of the
"as-declared" switches.
.. index:: --dictionary (gnatpp)
@@ -821,7 +828,7 @@ building specialized scripts.
:switch:`--dictionary=-, -D=-`
Do not use the default dictionary file;
instead, use the casing
- defined by a ``-n`` switch and any explicit
+ defined by a :switch:`-n` switch and any explicit
dictionary file(s)
The structure of a dictionary file, and details on the conventions
@@ -846,13 +853,13 @@ building specialized scripts.
.. index:: --max-line-length (gnatpp)
:switch:`--max-line-length={nnn}, -M={nnn}`
- Maximum line length, ``nnn`` from 32...256, the default value is 79
+ Maximum line length, ``nnn`` from 32...256. The default value is 79
.. index:: --indentation (gnatpp)
:switch:`--indentation={nnn}, -i={nnn}`
- Indentation level, ``nnn`` from 1...9, the default value is 3
+ Indentation level, ``nnn`` from 1...9. The default value is 3
.. index:: --indent-continuation (gnatpp)
@@ -878,8 +885,8 @@ building specialized scripts.
:switch:`--decimal-grouping={n}`
Put underscores in decimal literals (numeric literals without a base)
every ``n`` characters. If a literal already has one or more
- underscores, it is not modified. For example, with
- ``--decimal-grouping=3``, ``1000000`` will be changed to
+ underscores, ``gnatpp`` will not modify it. For example, with
+ ``--decimal-grouping=3``, ``1000000`` is changed to
``1_000_000``.
@@ -887,16 +894,16 @@ building specialized scripts.
:switch:`--based-grouping={n}`
Same as ``--decimal-grouping``, but for based literals. For
- example, with ``--based-grouping=4``, ``16#0001FFFE#`` will be
+ example, with ``--based-grouping=4``, ``16#0001FFFE#`` is
changed to ``16#0001_FFFE#``.
.. index:: --call-threshold (gnatpp)
:switch:`--call-threshold={nnn}`
- If the number of parameter associations is greater than ``nnn`` and if at
- least one association uses named notation, start each association from
- a new line. If ``nnn`` is 0, no check for the number of associations
- is made; this is the default.
+ If the number of parameter associations is greater than ``nnn``
+ and if at least one association uses named notation, start each
+ association from a new line. If ``nnn`` is 0, ``gnatpp`` does not
+ check for the number of associations; this is the default.
.. index:: --par-threshold (gnatpp)
@@ -904,7 +911,7 @@ building specialized scripts.
If the number of parameter specifications is greater than ``nnn``
(or equal to ``nnn`` in case of a function), start each specification from
a new line. If ``nnn`` is 0, and :switch:`--no-separate-is` was not
- specified, then the ``is`` is placed on a separate line. This feature is
+ specified, then the ``is`` is placed on a separate line. This option is
disabled by default.
@@ -913,8 +920,8 @@ building specialized scripts.
Setting the Source Search Path
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
- To define the search path for the input source file, ``gnatpp``
- uses the same switches as the GNAT compiler, with the same effects:
+ To define the search path for the input source file, pass ``gnatpp``
+ the same switches as the GNAT compiler, with the same effects:
.. index:: -I (gnatpp)
@@ -935,8 +942,8 @@ building specialized scripts.
Output File Control
^^^^^^^^^^^^^^^^^^^
- By default the output overwrites the input file.
- The output may be redirected by the following switches:
+ By default, the output overwrites the input file.
+ You can specify the location of the output with the following switches:
.. index:: --replace (gnatpp)
@@ -950,11 +957,11 @@ building specialized scripts.
.. index:: --output-dir (gnatpp)
:switch:`--output-dir={dir}`
- Generate output file in directory :file:`dir` with the same name as
- the input file. If :file:`dir` is the same as the directory
- containing the input file, the input file is not processed; use
- ``--replace`` if you want to update the input file in
- place.
+ Generate the output file in directory :file:`dir` with the same
+ name as the input file. If :file:`dir` is the same as the
+ directory containing the input file, ``gnatpp`` does not read or
+ process the input file; use ``--replace`` if you want to update
+ the input file in place.
.. index:: --pipe (gnatpp)
@@ -981,7 +988,7 @@ building specialized scripts.
.. index:: --replace-backup (gnatpp)
:switch:`--replace-backup, -r`
- Replace the input source file with the reformatted output, and copy the
+ Replace the input source file with the reformatted output and copy the
original input source into the file whose name is obtained by appending
the :file:`.npp` suffix to the name of the input file.
If a file with this name already exists, ``gnatpp`` terminates without
@@ -1018,11 +1025,13 @@ building specialized scripts.
* *b* - Brackets encoding (default value)
- Options ``--output-file`` and ``--output-force`` are allowed only if
- the call to gnatpp contains only one file to reformat.
+ You may only specify options :switch:`--output-file` and
+ :switch:`--output-force` if the call to ``gnatpp`` contains only
+ one file to reformat.
- Option ``--eol`` and ``--wide-character-encoding`` cannot be used together
- with the ``--pipe`` option.
+ You may not use the option :switch:`--eol` or
+ :switch:`--wide-character-encoding` together with the
+ :switch:`--pipe` option.
.. _Other_gnatpp_Switches:
@@ -1030,25 +1039,26 @@ building specialized scripts.
Other ``gnatpp`` Switches
^^^^^^^^^^^^^^^^^^^^^^^^^
- The additional ``gnatpp`` switches are defined in this subsection.
+ You can also use the additional ``gnatpp`` switches defined in
+ this subsection.
.. index:: --version (gnatpp)
:switch:`--version`
- Display copyright and version, then exit disregarding all other options.
+ Display copyright and version, then exit, disregarding all other options.
.. index:: --help (gnatpp)
:switch:`--help`
- Display usage, then exit disregarding all other options.
+ Display usage, then exit, disregarding all other options.
.. index:: -P (gnatpp)
:switch:`-P {file}`
- Indicates the name of the project file that describes the set of sources
+ Specifies the name of the project file that describes the set of sources
to be processed. The exact set of argument sources depends on other
options specified; see below.
@@ -1056,43 +1066,45 @@ building specialized scripts.
.. index:: -U (gnatpp)
:switch:`-U`
- If a project file is specified and no argument source is explicitly
- specified (either directly or by means of ``--files`` option), process
- all the units of the closure of the argument project. Otherwise this
- option has no effect.
+ If you specify a project file but don't specify a source file,
+ either directly or by means of a :switch:`--files` option,
+ ``gnatpp`` processes all the units of the closure of the
+ specifed project. Otherwise this option has no effect.
:switch:`-U {main_unit}`
- If a project file is specified and no argument source is explicitly
- specified (either directly or by means of ``--files`` option), process
- the closure of units rooted at ``main_unit``. Otherwise this option
- has no effect.
+ If you specify a project file but don't specify a source file,
+ either directly or by means of :switch:`--files` option,
+ ``gnatpp`` will process the closure of units rooted at
+ ``main_unit``. Otherwise this option has no effect.
.. index:: -X (gnatpp)
:switch:`-X{name}={value}`
- Indicates that external variable ``name`` in the argument project
- has the value ``value``. Has no effect if no project is specified.
+ Indicates that external variable ``name`` in the specified project
+ has the value ``value``. Has no effect if you don't specify a project.
.. index:: --RTS (gnatpp)
:switch:`--RTS={rts-path}`
- Specifies the default location of the runtime library. Same meaning as the
- equivalent ``gnatmake`` flag (:ref:`Switches_for_gnatmake`).
+ Specifies the default location of the runtime library. It has the
+ same meaning as the equivalent ``gnatmake`` switch
+ (:ref:`Switches_for_gnatmake`).
.. index:: --incremental (gnatpp)
:switch:`--incremental`
- Incremental processing on a per-file basis. Source files are only
- processed if they have been modified, or if files they depend on have
- been modified. This is similar to the way gnatmake/gprbuild only
- compiles files that need to be recompiled. A project file is required
- in this mode, and the gnat driver (as in *gnat pretty*) is not
- supported.
+
+ ``gnatpp`` will perform incremental processing on a per-file
+ basis. It will only process a source file if it has been
+ modified, or if files it depends on have been modified. This is
+ similar to the way ``gnatmake``/``gprbuild`` only compiles files that
+ need to be recompiled. You must specify a project file in this mode,
+ and the gnat driver (as in *gnat pretty*) is not supported.
(Note: this switch is not yet supported in the libadalang-based
- version of gnatpp.)
+ version of ``gnatpp``.)
.. index:: --pp-off (gnatpp)
@@ -1112,25 +1124,25 @@ building specialized scripts.
.. index:: --files (gnatpp)
:switch:`--files={filename}, -files={filename}`
- Take as arguments the files listed in text file ``file``.
- Text file ``file`` may contain empty lines that are ignored.
+ Take as arguments the files listed in text file ``file``, which
+ may contain empty lines that are ignored.
Each nonempty line should contain the name of an existing file.
- Several such switches may be specified simultaneously.
+ You may specify several such switches on the same command line.
.. index:: --ignore (gnatpp)
:switch:`--ignore={filename}`
- Do not process the sources listed in a specified file. This option cannot
- be used in incremental mode.
+ ``gnatpp`` will not process the sources listed in the specified file.
+ You can't specify this option in incremental mode.
.. index:: --jobs (gnatpp)
:switch:`--jobs={n}, -j={n}`
- With ``--incremental``, use *n* ``gnatpp`` processes to perform
- pretty printing in parallel. If *n* is 0, then the maximum number
- processes is the number of core processors on the platform.
+ With :switch:`--incremental`, use *n* ``gnatpp`` processes to perform
+ pretty printing in parallel. If *n* is 0, the maximum number
+ processes is the number of core processors on the host.
.. index:: --verbose (gnatpp)
@@ -1144,9 +1156,9 @@ building specialized scripts.
:switch:`--quiet, -q`
Quiet mode
- If a project file is specified and no argument source is explicitly
- specified (either directly or by means of ``--files`` option), and no
- ``-U`` is specified, then the set of processed sources is
+ If you specify a project file, but no source files
+ (either directly or by means of a :switch:`--files` option), and you
+ specify the :switch:`-U`, then the set of processed sources is
all the immediate units of the argument project.
@@ -1155,9 +1167,10 @@ building specialized scripts.
Formatting Rules
----------------
- The following subsections show how ``gnatpp`` treats, comments, program
- layout, name casing and how to disable ``gnatpp`` in source code regions.
- They provide more details of the switches shown above.
+ The following subsections show how ``gnatpp`` treats comments,
+ program layout, and name casing as well as how to disable ``gnatpp`` in
+ source code regions. They provide more details of the switches
+ shown above.
.. _Disabling_Pretty_Printing:
@@ -1165,20 +1178,20 @@ building specialized scripts.
Disabling Pretty Printing
^^^^^^^^^^^^^^^^^^^^^^^^^
- Pretty printing is highly heuristic in nature, and sometimes doesn't
- do exactly what you want. If you wish to format a certain region of
+ Pretty printing is highly heuristic in nature and sometimes doesn't
+ do exactly what you want. If you want to format a certain region of
code by hand, you can turn off pretty printing in that region by
surrounding it with special comments that start with ``--!pp off``
- and ``--!pp on``. The text in that region will then be reproduced
+ and ``--!pp on``. The text in that region is reproduced
verbatim in the output with no formatting.
- To disable pretty printing for the whole file, put ``--!pp off`` at
+ To disable pretty printing for an entire file, put ``--!pp off`` at
the top, with no following ``--!pp on``.
- The comments must appear on a line by themselves, with nothing
- preceding except spaces. The initial text of the comment must be
- exactly ``--!pp off`` or ``--!pp on`` (case sensitive), but may
- be followed by arbitrary additional text. For example:
+ You must place each of these comments on a line by themselves, with nothing
+ preceding except spaces. You must have the initial text of the comment be
+ exactly ``--!pp off`` or ``--!pp on`` (case sensitive), but you may
+ follow it by arbitrary additional text. For example:
.. code-block:: ada
@@ -1191,17 +1204,17 @@ building specialized scripts.
--!pp on -- reenable pretty printing
...
- You can specify different comment strings using the ``--pp-off``
- and ``--pp-on`` switches. For example, if you say:
+ You can specify different comment strings using the :switch:`--pp-off`
+ and :switch:`--pp-on` switches. For example, if you say:
::
$ gnatpp --pp-off=' pp-' *.ad?
- then gnatpp will recognize comments of the form
- ``-- pp-`` instead of ``--!pp off`` for disabling pretty
- printing. Note that the leading ``--`` of the comment is not
- included in the argument to these switches.
+ ``gnatpp`` will recognize comments of the form ``-- pp-`` instead
+ of ``--!pp off`` for disabling pretty printing. Note that you do
+ not include the leading ``--`` of the comment in the argument to
+ these switches.
.. _Formatting_Comments:
@@ -1209,17 +1222,17 @@ building specialized scripts.
Formatting Comments
^^^^^^^^^^^^^^^^^^^
- Only ``--layout=compact`` and ``--layout=tall`` format comments.
+ Only :switch:`--layout=compact` and :switch:`--layout=tall` format comments.
Comments in Ada code are of two kinds:
- * a *whole-line comment*, which appears by itself (possibly preceded by
+ * *whole-line comments*, which appear by themselves (possibly preceded by
white space) on a line
- * an *end-of-line comment*, which follows some other Ada code on
+ * *end-of-line comments*, which follows some other Ada code on
the same line.
- A whole-line comment is indented according to the surrounding code,
+ ``gnatpp`` indents whole-line comment according to the surrounding code,
with some exceptions. Comments that start in column 1 are kept
there. If possible, comments are not moved so far to the right that
the maximum line length is exceeded. Special-form comments such as
@@ -1227,16 +1240,17 @@ building specialized scripts.
For an end-of-line comment, ``gnatpp`` tries to leave the same
number of spaces between the end of the preceding Ada code and the
- beginning of the comment as appear in the original source.
+ beginning of the comment, as it appears in the original source.
For each whole-line comment that does not end with two hyphens or that are
not special-form comments, ``gnatpp`` inserts spaces if necessary after the
starting two hyphens to ensure that there are at least two spaces between
these hyphens and the first non-blank character of the comment.
- With ``--layout=compact``, whole-line comments that form a paragraph will be
- filled in typical word processor style (that is, moving words between lines
- to make the lines other than the last similar in length).
+ With :switch:`--layout=compact`, ``gnatpp`` fills in whole-line
+ comments that form a paragraph in typical word processor style
+ (that is, moving words between lines to make the lines other than
+ the last similar in length).
.. _Name_Casing:
@@ -1247,22 +1261,23 @@ building specialized scripts.
``gnatpp`` always converts the usage occurrence of a (simple) name to
the same casing as the corresponding defining identifier.
- You control the casing for defining occurrences via the ``--name...``
- switches. With ``--name-case-as-declared``, which is the default,
+ You control the casing for defining occurrences via the :switch:`--name...`
+ switches. With :switch:`--name-case-as-declared`, which is the default,
defining occurrences appear exactly as in the source file where they
are declared. The other values for this switch --
- ``--name-upper-case``, ``--name-lower-case``, ``--name-mixed-case``
+ :switch:`--name-upper-case`, :switch:`--name-lower-case`, and
+ :switch:``--name-mixed-case``
-- result in upper, lower, or mixed case, respectively. If
``gnatpp`` changes the casing of a defining occurrence, it
- analogously changes the casing of all the usage occurrences of this
+ similarly changes the casing of all the usage occurrences of this
name.
- If the defining occurrence of a name is not in the source compilation
- unit currently being processed by ``gnatpp``, the casing of each
- reference to this name is changed according to the switch (subject to
- the dictionary file mechanism described below). Thus ``gnatpp`` acts
- as though the switch had affected the casing for the defining
- occurrence of the name.
+ If the defining occurrence of a name is not in the source
+ compilation unit currently being processed by ``gnatpp``,
+ ``gnatpp`` changes the casing of each reference to this name
+ according to the switch (subject to the dictionary file mechanism
+ described below). Thus ``gnatpp`` acts as though the switch had
+ affected the casing for the defining occurrence of the name.
The options
:switch:`--attribute...`,
@@ -1276,37 +1291,36 @@ building specialized scripts.
types, named numbers and pragmas, respectively.
:switch:`--type...` cover subtypes as well.
- Some names may need to be spelled with casing conventions that are not
- covered by the upper-, lower-, and mixed-case transformations.
- You can arrange correct casing by placing such names in a
- *dictionary file*,
- and then supplying a ``--dictionary`` switch.
- The casing of names from dictionary files overrides
- any ``--name...`` switch.
-
- To handle the casing of Ada predefined names and the names from GNAT libraries,
- ``gnatpp`` assumes a default dictionary file.
- The name of each predefined entity is spelled with the same casing as is used
- for the entity in the :title:`Ada Reference Manual` (usually mixed case).
- The name of each entity in the GNAT libraries is spelled with the same casing
- as is used in the declaration of that entity.
-
- The ``--dictionary=-`` switch suppresses the use of
- the default dictionary file. Instead, the casing for predefined and
- GNAT-defined names will be established by the
- ``-n`` switch or explicit dictionary files. For
- example, by default the names ``Ada.Text_IO`` and
- ``GNAT.OS_Lib`` will appear as just shown, even in the presence of
- a ``--name-upper-case`` switch. To ensure that even
- such names are rendered in uppercase, additionally supply the
- --dictionary=- switch (or else place these names
- in upper case in a dictionary file).
-
- A dictionary file is a plain text file; each line in this file can be
+ You may need some names to be spelled with casing conventions that
+ are not covered by the upper-, lower-, and mixed-case
+ transformations. You can have ``gnatpp`` produce the correct
+ casing by placing such names in a *dictionary file*, and
+ specifying a :switch:`--dictionary` switch. Specifying any
+ dictionary files overrides any :switch:`--name...` switch.
+
+ ``gnatpp`` uses a default dictionary file to choose the casing of
+ Ada predefined names and the names from GNAT libraries,
+
+ Each predefined entity is converted to the same casing as
+ the entity in the :title:`Ada Reference Manual` (usually
+ mixed case) and each entity in the GNAT libraries is cased
+ the same as its declaration in the library.
+
+ You can specify the :switch:`--dictionary=-` switch to suppress
+ the use of the default dictionary file. Instead, the casing for
+ predefined and GNAT-defined names is given by the :switch:`-n`
+ switch or explicit dictionary files. For example, by default the
+ names ``Ada.Text_IO`` and ``GNAT.OS_Lib`` appear as just shown,
+ even in the presence of a :switch:`--name-upper-case` switch. To
+ ensure that even such names are rendered in uppercase, you must
+ specify the :switch:`--dictionary=-` switch or place these names
+ in upper case in a dictionary file.
+
+ A dictionary file is a plain text file; each line in this file is
either a blank line (containing only space characters), an Ada comment
line, or the specification of exactly one *casing schema*.
- A casing schema is a string that has the following syntax:
+ A casing schema is a string with the following syntax:
::
@@ -1318,36 +1332,38 @@ building specialized scripts.
(See :title:`Ada Reference Manual`, Section 2.3) for the definition of the
``identifier`` lexical element and the ``letter_or_digit`` category.)
- The casing schema string can be followed by white space and/or an Ada-style
- comment; any amount of white space is allowed before the string.
+ You can follow a casing schema string by white space and/or an Ada-style
+ comment. You can also have any amount of white space before the string.
- If a dictionary file is passed as
- the value of a :switch:`--dictionary={file}` switch
- then for every
- simple name and every identifier, ``gnatpp`` checks if the dictionary
- defines the casing for the name or for some of its parts (the term 'subword'
- is used below to denote the part of a name which is delimited by '_' or by
- the beginning or end of the word and which does not contain any '_' inside):
+ If you pass a dictionary file as the value of a
+ :switch:`--dictionary={file}` switch, ``gnatpp`` checks every
+ simple name and identifier to see if the dictionary defines
+ the casing for the name or for some of its parts (the term
+ 'subword' is used below to denote the part of a name that is
+ delimited by '_' or by the beginning or end of the word that
+ doesn't contain any '_' characters):
- * if the whole name is in the dictionary, ``gnatpp`` uses for this name
- the casing defined by the dictionary; no subwords are checked for this word
+ * if the complete name is in the dictionary, ``gnatpp`` uses the
+ casing defined by the dictionary for this name; it does not check
+ any subwords
- * for every subword ``gnatpp`` checks if the dictionary contains the
- corresponding string of the form ``simple_identifier``,
- and if it does, the casing of this ``simple_identifier`` is used
- for this subword
+ * for every subword, ``gnatpp`` checks if the dictionary contains
+ the corresponding string of the form ``simple_identifier``, and
+ if it does, the casing of this ``simple_identifier`` is used for
+ this subword
- * if the whole name does not contain any '_' inside, and if for this name
- the dictionary contains two entries -- one of the form ``identifier``,
- and another of the form ``simple_identifier`` -- then the first one
- is applied to define the casing of this name
+ * if the complete name does not contain any '_' characters and if
+ for this name the dictionary contains two entries -- one of the
+ form ``identifier``, and another of the form
+ ``simple_identifier`` -- ``gnatpp`` uses the first one to obtain
+ the casing of this name
- * if more than one dictionary file is passed as ``gnatpp`` switches, each
- dictionary adds new casing exceptions and overrides all the existing casing
- exceptions set by the previous dictionaries
+ * if you pass more than one dictionary file as ``gnatpp`` switches,
+ each dictionary adds new casing exceptions and overrides all the
+ existing casing exceptions set by the previous dictionaries
* when ``gnatpp`` checks if the word or subword is in the dictionary,
- this check is not case sensitive
+ it uses a check that's not case sensitive
For example, suppose we have the following source to reformat:
@@ -1380,7 +1396,7 @@ building specialized scripts.
$ gnatpp --name-mixed-case --dictionary=dict1 --dictionary=dict2 test.adb
- then we will get the following name casing in the ``gnatpp`` output:
+ then we get the following name casing in the ``gnatpp`` output:
.. code-block:: ada
@@ -1400,9 +1416,9 @@ building specialized scripts.
^^^^^^^^^^^^^^^^^^^^^^^
``gnatpp`` has some support for preprocessor directives.
- You can use preprocessor symbols, as in ``$symbol``.
- In addition, you can use conditional compilation,
- so long as the program text is syntactically legal Ada code
+ You can use preprocessor symbols such as ``$symbol``.
+ In addition, you can use conditional compilation as
+ long as the program text is syntactically legal Ada code
after removing all the preprocessor directives (lines starting
with ``#``). For example, ``gnatpp`` can format the following:
@@ -1480,8 +1496,8 @@ building specialized scripts.
.. index:: --compact (gnatpp)
:switch:`--compact, --no-compact`
- In calls and similar, ``--compact`` packs as many
- subexpressions on the same line as possible. Example:
+ In calls and similar constructs, :switch:`--compact` packs as many
+ subexpressions into the same line as is possible. Example:
.. code-block:: ada
@@ -1489,10 +1505,11 @@ building specialized scripts.
(Short_One, Another_Short_One,
A_Very_Very_Very_Very_Very_Very_Very_Very_Long_One);
- On the contrary, with ``--no-compact``, in calls and similar, if it is
- necessary to split a line between two subexpressions (because otherwise
- the construct would exceed --max-line-length), then all such
- subexpressions are placed on separate lines. Example:
+ On the other hand, if you specify :switch:`--no-compact`,
+ ``gnatpp`` places all such subexpressions on separate lines if
+ it's necessary to split a line between two subexpressions to
+ avoid the construct exceeding :switch:`--max-line-length`. For
+ example:
.. code-block:: ada
@@ -1546,15 +1563,14 @@ building specialized scripts.
.. index:: --indent-named-statements (gnatpp)
:switch:`--indent-named-statements, --no-indent-named-statements`
- Named block and loop statements are indented with respect to
- the name.
+ Indent block and loop statements with respect to the name.
.. index:: --split-line-before-op (gnatpp)
- :switch:`--split-line-before-op, --no-split-line-before-op`
- If it is necessary to split a line at a binary operator, by default
- the line is split after the operator. With this option, it is split
- before the operator.
+ :switch:`--split-line-before-op, --no-split-line-before-op` If it
+ is necessary to split a line at a binary operator, by default the
+ line is split after the operator. When you specify this switch,
+ it is split before the operator.
.. index:: --use-on-new-line (gnatpp)
@@ -1656,7 +1672,7 @@ building specialized scripts.
.. index:: ! gnatstub
``gnatstub`` creates empty but compilable bodies
- for library unit declarations, and empty but compilable
+ for library unit declarations and empty but compilable
subunits for body stubs.
``gnatstub`` is a project-aware tool.
@@ -1668,17 +1684,17 @@ building specialized scripts.
``gnatstub`` switches is named ``gnatstub``.
- By default, all the program unit bodies generated by ``gnatstub``
+ By default, all program unit bodies generated by ``gnatstub``
raise ``Program_Error``, which will catch accidental calls of
- generated stubs. This behavior can be changed with option
- ``--no-exception`` (see below).
+ generated stubs. You can change this behavior with switch
+ :switch:`--no-exception` (see below).
.. _Running_gnatstub:
Running ``gnatstub``
--------------------
- ``gnatstub`` invocation has the following form:
+ You invoke ``gnatstub`` like this:
::
@@ -1686,25 +1702,22 @@ building specialized scripts.
where
- * *filename*
- is the name of the source file that contains a library unit declaration
- for which a body must be created or a library unit body for which subunits
- must be created for the body stubs declared in this body.
- The file name may contain path information.
- If the name does not follow GNAT file naming conventions and the set
- of switches does not contain a project file that defines naming
- conventions, the name of the body file must
- be provided
- explicitly as the value of the :switch:`--output={body-name}` option.
- If the file name follows the GNAT file naming
- conventions and the name of the body file is not provided,
- ``gnatstub``
- takes the naming conventions for the generated source from the
- project file provided as a parameter of ``-P`` switch if any,
- or creates the name file to generate using the standard GNAT
- naming conventions.
-
- Note that it is no longer necessary to specify the Ada language version;
+ * *filename* is the name of the source file that contains a library
+ unit declaration for which you want a body to be created or a
+ library unit body for which you want subunits to be created for
+ the body stubs declared in this body. The file name may contain
+ path information. If the name does not follow GNAT file naming
+ conventions and the set of switches does not contain a project
+ file that defines naming conventions, you must explicitly
+ provide the name of the body file as the value of the
+ :switch:`--output={body-name}` switch. If the file name follows
+ the GNAT file naming conventions and you do not provide the name
+ of the body file ``gnatstub`` uses the naming conventions for
+ the generated source from the project file provided as a
+ parameter of a :switch:`-P` switch if any, or creates the name file
+ using the standard GNAT naming conventions.
+
+ Note that you no longer need to specify the Ada language version;
``gnatstub`` can process Ada source code written in any version from
Ada 83 onward without specifying any language version switch.
@@ -1720,21 +1733,22 @@ building specialized scripts.
.. index:: --version (gnatstub)
:switch:`--version`
- Display copyright and version, then exit disregarding all other options.
+ Display copyright and version, then exit, disregarding all other options.
.. index:: --help (gnatstub)
:switch:`--help`
- Display usage, then exit disregarding all other options.
+ Display usage, then exit, disregarding all other options.
.. index:: -P (gnatstub)
:switch:`-P {file}`
- Indicates the name of the project file that describes the set of sources
- to be processed. An aggregate project is allowed as the file parameter only
- if it has exactly one non-aggregate project being aggregated.
+ Indicates the name of the project file that describes the set of
+ sources to be processed. You can specify an aggregate project as
+ the file parameter only if it has exactly one non-aggregate
+ project being aggregated.
.. index:: -X (gnatstub)
@@ -1747,14 +1761,15 @@ building specialized scripts.
.. index:: --RTS (gnatstub)
:switch:`--RTS={rts-path}`
- Specifies the default location of the runtime library. Same meaning as the
- equivalent ``gnatmake`` flag (:ref:`Switches_for_gnatmake`).
+ Specifies the default location of the runtime library. It has the
+ same meaning as the equivalent ``gnatmake`` flag
+ (:ref:`Switches_for_gnatmake`).
.. index:: --subunits (gnatstub)
:switch:`--subunits`
- Generate subunits for body stubs. If this switch is specified,
+ Generate subunits for body stubs. If you specify this switch,
``gnatstub`` expects a library unit body as an argument file;
otherwise a library unit declaration is expected. If a body stub
already has a corresponding subunit, ``gnatstub`` does not
@@ -1767,7 +1782,7 @@ building specialized scripts.
If the destination directory already contains a file with the name of the
body file
for the argument spec file, replace it with the generated body stub.
- This switch cannot be used together with ``--subunits``.
+ This switch cannot be used together with :switch:`--subunits`.
.. index:: --comment-header-spec (gnatstub)
@@ -1794,8 +1809,8 @@ building specialized scripts.
:switch:`--max-line-length={n}`
(``n`` is a non-negative integer). Set the maximum line length for
- the output files. The default is 79. The maximum value that can be
- specified is 32767.
+ the output files. The default is 79. The maximum value that you can
+ specify is 32767.
.. index:: --indentation (gnatstub)
@@ -1809,51 +1824,51 @@ building specialized scripts.
.. index:: --alphabetical-order (gnatstub)
:switch:`--alphabetical-order`
- Order local bodies alphabetically. (By default local bodies are ordered
+ Order local bodies alphabetically. By default local bodies are ordered
in the same way as the corresponding local specs in the argument
- spec file.)
+ spec file.
.. index:: --no-exception (gnatstub)
:switch:`--no-exception`
Avoid raising Program_Error in the generated bodies of program unit stubs,
- except in the case of functions, where we have no value to return.
+ except in the case of functions, where there will be value to return.
.. index:: --no-local-header (gnatstub)
:switch:`--no-local-header`
- Do not place local comment header with unit name before body stub for a
+ Do not place a local comment header with unit name before body stub for a
unit.
.. index:: --files (gnatstub)
:switch:`--files={filename}`
- Take as arguments the files listed in text file ``file``.
- Text file ``file`` may contain empty lines that are ignored.
- Each nonempty line should contain the name of an existing file.
- Several such switches may be specified.
+ Take as arguments the files listed in text file ``file``, which
+ may contain empty lines that are ignored.
+ You should specify the name of an existing file in each non-empty line.
+ You may specify multiple :switch:`--files=` switches.
.. index:: --output (gnatstub)
- :switch:`--output={body-name}`
- Body file name. This should be set if the argument file name does
- not follow the default GNAT file naming conventions, and the naming
- conventions are not specified by a project file. If this switch and
- ``-P`` are both omitted, the name for the body will be obtained
- according to the default GNAT file naming conventions.
+ :switch:`--output={body-name}` Body file name. You should set this
+ if the argument file name does not follow the default GNAT file
+ naming conventions and the naming conventions are not specified by
+ a project file. If you omit both this switch and :switch:`-P`,
+ ``gnatpp`` will choose the name for the body according to the
+ default GNAT file naming conventions.
.. index:: --output-dir (gnatstub)
- :switch:`--output-dir={dir-name}`
- The directory in which to place the output files.
- If this switch is not set, the generated library unit body is
- placed in the current directory, and generated sununits
- in the directory where the argument body is located.
+ :switch:`--output-dir={dir-name}` The directory in which to place
+ the output files. If you do not specify this switch, ``gnatpp``
+ places the generated library unit body in the current directory
+ and generated sununits in the directory where the argument body is
+ located.
.. index:: --wide-character-encoding (gnatstub)
@@ -1961,7 +1976,7 @@ building specialized scripts.
$ gnatsymbolize [ switches ] filename [ addresses ]
- For instance, consider the following Ada program:
+ For example, consider the following Ada program:
.. code-block:: ada
@@ -2022,7 +2037,7 @@ building specialized scripts.
This program, when built and run, prints a list of addresses which
correspond to the traceback when inside function ``Call_Me_Third``.
- For instance, on x86-64 GNU/Linux:
+ For example, on x86-64 GNU/Linux:
::
@@ -2035,8 +2050,8 @@ building specialized scripts.
0x00005586C9D8128C
0x00005586C9D81069
- ``gnatsymbolize`` can be used to translate those addresses into
- code locations as follow:
+ You can use ``gnatsymbolize`` to translate those addresses into
+ code locations as follows:
::
@@ -2052,7 +2067,7 @@ building specialized scripts.
Switches for ``gnatsymbolize``
------------------------------
- ``gnatsymbolize`` recognizes the following switches:
+ You can specify the following switches for ``gnatsymbolize``:
.. index:: --help (gnatsymbolize)
@@ -2062,7 +2077,7 @@ building specialized scripts.
:switch:`--cache`
Read the symbolic information from the executable and cache them
- in memory in order to accelerate the translation of each address
+ in memory to accelerate the translation of each address
into a symbolic location.
Depending on the size of the executable and the number of addresses
@@ -2070,13 +2085,13 @@ building specialized scripts.
overall.
:switch:`--dump`
- If :switch:`--cache` is used, dump the contents of the cache on
+ If you have specified :switch:`--cache`, dump the contents of the cache to
Standard Output. Has no effect otherwise.
:switch:`--count={N}`
- Compute the symbolic traceback ``N`` times in a row. This option
- is mostly useful for measuring the performance of ``gnatsymbolize``,
- particularly in the case where the cache is being used.
+ Compute the symbolic traceback ``N`` times in a row. You use this switch
+ mostly for measuring the performance of ``gnatsymbolize``,
+ particularly in the case where you have specified the cache to be used.
:switch:`--load`
Interpret the first address as the load address of the executable.
@@ -2086,14 +2101,14 @@ building specialized scripts.
----------------------------------
The translation is performed by reading the DWARF debugging
- information produced by the compiler for each unit. All units
- for which the translation is to be done must therefore be compiled
- such that DWARF debugging information is produced. In most cases,
- this is done by simply compiling with ``-g``.
+ information produced by the compiler for each unit. You must
+ therefore compile all units for which the translation is to be done
+ in a way that DWARF debugging information is produced. In most cases,
+ you do this by simply compiling with :switch:`-g`.
This program provides a functionality similar to ``addr2line``.
It has fewer options to tailor its output, but has been designed
- to require fewer of the DWARF sections to be present in the
+ to require fewer DWARF sections to be present in the
executable. In particular, it works for code compiled with ``-g1``.
@@ -2104,7 +2119,7 @@ building specialized scripts.
Using Project Files with GNAT Tools
===================================
- This section describes how project files can be used in conjunction
+ This section describes how you can use project files in conjunction
with a number of GNAT tools.
For a comprehensive description of project files and the overall
GNAT Project Manager facility, please refer to the
@@ -2129,18 +2144,18 @@ building specialized scripts.
specified, see below.
:switch:`-U`
- If a project file is supplied, say for project ``proj``,
- but no sources are specified for ``proj`` (either by a
+ If you supply a project file, say for project ``proj``,
+ but you don't specify any sources for ``proj`` (either by a
project attribute or through a tool option that provides a list
of the files to be used), process all the source files
from projects imported either directly or indirectly by ``proj``.
Otherwise this option has no effect.
:switch:`-U {source_file}`
- Similar to :switch:`-U`, but if no sources are specified then
+ Similar to :switch:`-U`, but if you don't specify any sources,
process only those source files for units in the closure of
the Ada source contained in ``source_file``. Note that this option
- expects the source file name but not the Ada unit name as its
+ expects the source file name, not the Ada unit name, as its
parameter.
:switch:`-X{name}={val}`
@@ -2148,25 +2163,28 @@ building specialized scripts.
value ``val``. Has no effect if no project has been specified.
:switch:`--subdirs={dir}`
- Use the ``dir`` subdirectory of the project's object directory (or the ``dir``
- subdirectory of the project file directory if the project does not specify
- an object directory) for tool output files. Has no effect if no project
- has been specified or if :switch:`--no-objects-dir` is specified.
+ Use the ``dir`` subdirectory of the project's object directory
+ (or the ``dir`` subdirectory of the project file directory if
+ the project does not specify an object directory) for tool
+ output files. Has no effect if you haven't specified a project
+ and if you haven't specified the if :switch:`--no-objects-dir`
+ switch.
:switch:`--no-objects-dir`
- Place all the result files into the current directory (i.e., the directory
- from which the tool invocation command is issued) instead of the project's
- object directory. Has no effect if no project has been specified.
+ Place all the result files into the current directory (i.e., the
+ directory from which the tool invocation command is issued)
+ instead of the project's object directory. Has no effect if you
+ haven't specified a project.
:switch:`-eL`
Follow all symbolic links when processing project files.
- If a project file is specified and there is neither a :switch:`-U` option,
- nor a :switch:`-U {main_unit}` option, nor some other explicit option to
+ If you specify a project file but neither a :switch:`-U` option,
+ nor a :switch:`-U {main_unit}` option, nor any other explicit option to
specify the source files, then the sources to be processed are the
immediate sources of the specified project (i.e., the source files directly
defined by that project, either implicitly by residing in the project
- source directories, or explicitly through any of the source-related
+ source directories or explicitly through any of the source-related
attributes).
.. _Tool-specific_packages_in_project files:
@@ -2178,7 +2196,8 @@ building specialized scripts.
the package names are given elsewhere in this manual, in the sections that describe
the respective tools.
- A tool-specific package in a project file may define the ``Default_Switches``
- attribute indexed by "ada" (as language name). The value of this attribute
- is a list of switches that will be supplied at tool invocation.
- Project-specific switches cannot be specified through this attribute.
+ A tool-specific package in a project file may define the
+ ``Default_Switches`` attribute indexed by "ada" (as language
+ name). You set the value of this attribute to a list of switches
+ that you want the tool to use when it's invoked. You cannot
+ specify project-specific switches through this attribute.
@@ -9,10 +9,10 @@ Inline Assembler
.. index:: Inline Assembler
If you need to write low-level software that interacts directly
-with the hardware, Ada provides two ways to incorporate assembly
+with the hardware, Ada provides two ways for you to incorporate assembly
language code into your program. First, you can import and invoke
external routines written in assembly language, an Ada feature fully
-supported by GNAT. However, for small sections of code it may be simpler
+supported by GNAT. However, for small sections of code, it may be simpler
or more efficient to include assembly language statements directly
in your Ada source program, using the facilities of the implementation-defined
package ``System.Machine_Code``, which incorporates the gcc
@@ -24,14 +24,14 @@ including the following:
* Automatic usage of the proper calling conventions
* Access to Ada constants and variables
* Definition of intrinsic routines
-* Possibility of inlining a subprogram comprising assembler code
+* Possibility of inlining a subprogram consisting of assembler code
* Code optimizer can take Inline Assembler code into account
This appendix presents a series of examples to show you how to use
the Inline Assembler. Although it focuses on the Intel x86,
the general approach applies also to other processors.
-It is assumed that you are familiar with Ada
-and with assembly language programming.
+It is assumed you are familiar with both Ada
+and assembly language programming.
.. _Basic_Assembler_Syntax:
@@ -99,9 +99,9 @@ pre-processor) documentation for further information.
A Simple Example of Inline Assembler
====================================
-The following example will generate a single assembly language statement,
+The following example generate a single assembly language statement,
``nop``, which does nothing. Despite its lack of run-time effect,
-the example will be useful in illustrating the basics of
+the example is useful in illustrating the basics of
the Inline Assembler facility.
.. code-block:: ada
@@ -114,18 +114,18 @@ the Inline Assembler facility.
``Asm`` is a procedure declared in package ``System.Machine_Code``;
here it takes one parameter, a *template string* that must be a static
-expression and that will form the generated instruction.
+expression that produces the generated instruction.
``Asm`` may be regarded as a compile-time procedure that parses
-the template string and additional parameters (none here),
-from which it generates a sequence of assembly language instructions.
+the template string and any additional parameters (none, in this case)
+and generates one or more assembly language instructions.
The examples in this chapter will illustrate several of the forms
for invoking ``Asm``; a complete specification of the syntax
is found in the ``Machine_Code_Insertions`` section of the
:title:`GNAT Reference Manual`.
-Under the standard GNAT conventions, the ``Nothing`` procedure
-should be in a file named :file:`nothing.adb`.
+Under the standard GNAT conventions, you should put the ``Nothing`` procedure
+in a file named :file:`nothing.adb`.
You can build the executable in the usual way:
::
@@ -155,7 +155,7 @@ where the options are:
do not add runtime checks
This gives a human-readable assembler version of the code. The resulting
-file will have the same name as the Ada source file, but with a ``.s``
+file has the same name as the Ada source file but with a ``.s``
extension. In our example, the file :file:`nothing.s` has the following
contents:
@@ -183,8 +183,8 @@ can differ on different targets. For example, GNU/Linux uses '#APP' while
on NT you will see '/APP'.
If you make a mistake in your assembler code (such as using the
-wrong size modifier, or using a wrong operand for the instruction) GNAT
-will report this error in a temporary file, which will be deleted when
+wrong size modifier or using a wrong operand for the instruction) GNAT
+will report this error in a temporary file, which is deleted when
the compilation is finished. Generating an assembler file will help
in such cases, since you can assemble this file separately using the
``as`` assembler that comes with gcc.
@@ -197,7 +197,7 @@ Assembling the file using the command
will give you error messages whose lines correspond to the assembler
input file, so you can easily find and correct any mistakes you made.
-If there are no errors, ``as`` will generate an object file
+If there are no errors, ``as`` generates an object file called
:file:`nothing.out`.
@@ -227,10 +227,10 @@ statements.
Put_Line ("Flags register:" & Flags'Img);
end Get_Flags;
-In order to have a nicely aligned assembly listing, we have separated
-multiple assembler statements in the Asm template string with linefeed
-(ASCII.LF) and horizontal tab (ASCII.HT) characters.
-The resulting section of the assembly output file is:
+We have separated multiple assembler statements in the Asm template
+string with linefeed (ASCII.LF) and horizontal tab (ASCII.HT)
+characters in order to have a nicely aligned assembly listing. The
+resulting section of the assembly output file is:
::
@@ -269,20 +269,21 @@ In the generated assembly code, one of the percent signs will be stripped off.
Names such as ``%0``, ``%1``, ``%2``, etc., denote input or output
variables: operands you later define using ``Input`` or ``Output``
parameters to ``Asm``.
-An output variable is illustrated in
-the third statement in the Asm template string:
+An output variable is shown in
+the third section of the Asm template string:
::
movl %%eax, %0
-The intent is to store the contents of the eax register in a variable that can
-be accessed in Ada. Simply writing ``movl %%eax, Flags`` would not
-necessarily work, since the compiler might optimize by using a register
-to hold Flags, and the expansion of the ``movl`` instruction would not be
-aware of this optimization. The solution is not to store the result directly
-but rather to advise the compiler to choose the correct operand form;
-that is the purpose of the ``%0`` output variable.
+The intent of this section is to store the contents of the ``eax``
+register in a variable that can be accessed in Ada. Simply writing
+``movl %%eax, Flags`` would not necessarily work, since the compiler
+might optimize by using a register to hold ``Flags``, and the expansion of
+the ``movl`` instruction would not be aware of this optimization. The
+solution is not to store the result directly but rather to advise the
+compiler to choose the correct operand form; that is the purpose of
+the ``%0`` output variable.
Information about the output variable is supplied in the ``Outputs``
parameter to ``Asm``:
@@ -292,14 +293,14 @@ parameter to ``Asm``:
Outputs => Unsigned_32'Asm_Output ("=g", Flags));
The output is defined by the ``Asm_Output`` attribute of the target type;
-the general format is
+the general format is:
.. code-block:: ada
Type'Asm_Output (constraint_string, variable_name)
The constraint string directs the compiler how
-to store/access the associated variable. In the example
+to store/access the associated variable. In the example:
.. code-block:: ada
@@ -316,14 +317,14 @@ the optimizer from keeping it in a register. In contrast,
uses the ``"r"`` (register) constraint, telling the compiler to
store the variable in a register.
-If the constraint is preceded by the equal character '=', it tells
-the compiler that the variable will be used to store data into it.
+If you precede the constraint with the equal character ('='), it tells
+the compiler that the variable will have data stored into it.
In the ``Get_Flags`` example, we used the ``"g"`` (global) constraint,
-allowing the optimizer to choose whatever it deems best.
+allowing the optimizer to choose whatever operand it deems best.
There are a fairly large number of constraints, but the ones that are
-most useful (for the Intel x86 processor) are the following:
+most useful for the Intel x86 processor are the following:
====== ==========================================
*=* output constraint
@@ -340,9 +341,9 @@ most useful (for the Intel x86 processor) are the following:
*q* use one of eax, ebx, ecx, edx, esi or edi
====== ==========================================
-The full set of constraints is described in the gcc and ``as``
-documentation; note that it is possible to combine certain constraints
-in one constraint string.
+The full set of constraints is described in the ``gcc`` and ``as``
+documentation; note that you can combine certain constraints
+into one constraint string.
You specify the association of an output variable with an assembler operand
through the :samp:`%{n}` notation, where *n* is a non-negative
@@ -356,9 +357,8 @@ integer. Thus in
Outputs => Unsigned_32'Asm_Output ("=g", Flags));
-``%0`` will be replaced in the expanded code by the appropriate operand,
-whatever
-the compiler decided for the ``Flags`` variable.
+``%0`` is replaced in the expanded code by the appropriate operand,
+whatever the compiler chose for the ``Flags`` variable.
In general, you may have any number of output variables:
@@ -381,8 +381,8 @@ For example:
where ``Var_A``, ``Var_B``, and ``Var_C`` are variables
in the Ada program.
-As a variation on the ``Get_Flags`` example, we can use the constraints
-string to direct the compiler to store the eax register into the ``Flags``
+As a variation on the ``Get_Flags`` example, we can use the constraint
+string to direct the compiler to store the ``eax`` register into the ``Flags``
variable, instead of including the store instruction explicitly in the
``Asm`` template string:
@@ -402,7 +402,7 @@ variable, instead of including the store instruction explicitly in the
end Get_Flags_2;
The ``"a"`` constraint tells the compiler that the ``Flags``
-variable will come from the eax register. Here is the resulting code:
+variable will come from the ``eax`` register. Here is the resulting code:
::
@@ -415,7 +415,7 @@ variable will come from the eax register. Here is the resulting code:
The compiler generated the store of eax into Flags after
expanding the assembler code.
-Actually, there was no need to pop the flags into the eax register;
+In fact, there was no need to pop the flags into the ``eax`` register;
more simply, we could just pop the flags directly into the program variable:
.. code-block:: ada
@@ -441,7 +441,7 @@ Input Variables in Inline Assembler
The example in this section illustrates how to specify the source operands
for assembly language statements.
-The program simply increments its input value by 1:
+The procedure simply increments its input value by 1:
.. code-block:: ada
@@ -469,27 +469,27 @@ The program simply increments its input value by 1:
end Increment;
The ``Outputs`` parameter to ``Asm`` specifies
-that the result will be in the eax register and that it is to be stored
+that the result is in the ``eax`` register and that it is to be stored
in the ``Result`` variable.
The ``Inputs`` parameter looks much like the ``Outputs`` parameter,
but with an ``Asm_Input`` attribute.
The ``"="`` constraint, indicating an output value, is not present.
-You can have multiple input variables, in the same way that you can have more
+You can have multiple input variables in the same way you can have more
than one output variable.
The parameter count (%0, %1) etc, still starts at the first output statement,
and continues with the input statements.
Just as the ``Outputs`` parameter causes the register to be stored into the
-target variable after execution of the assembler statements, so does the
-``Inputs`` parameter cause its variable to be loaded into the register
+target variable after execution of the assembler statements, the
+``Inputs`` parameter causes its variable to be loaded into the register
before execution of the assembler statements.
Thus the effect of the ``Asm`` invocation is:
-* load the 32-bit value of ``Value`` into eax
+* load the 32-bit value of ``Value`` into ``eax``
* execute the ``incl %eax`` instruction
* store the contents of eax into the ``Result`` variable
@@ -520,7 +520,7 @@ frame) can be significant, compared to the amount of code in the subprogram
body. A solution is to apply Ada's ``Inline`` pragma to the subprogram,
which directs the compiler to expand invocations of the subprogram at the
point(s) of call, instead of setting up a stack frame for out-of-line calls.
-Here is the resulting program:
+Here's the resulting program:
.. code-block:: ada
@@ -593,14 +593,14 @@ such as Ada is that the compiler needs to be aware of which registers are
being used by the assembly code. In some cases, such as the earlier examples,
the constraint string is sufficient to indicate register usage (e.g.,
``"a"`` for
-the eax register). But more generally, the compiler needs an explicit
+the ``eax`` register). But, more generally, the compiler needs an explicit
identification of the registers that are used by the Inline Assembly
statements.
Using a register that the compiler doesn't know about
-could be a side effect of an instruction (like ``mull``
-storing its result in both eax and edx).
-It can also arise from explicit register usage in your
+could be a side effect of an instruction (like ``mull``, which
+stores its result into both ``eax`` and ``edx``).
+It can also arise from explicit register usage within your
assembly code; for example:
.. code-block:: ada
@@ -611,10 +611,10 @@ assembly code; for example:
Inputs => Unsigned_32'Asm_Input ("g", Var_In));
where the compiler (since it does not analyze the ``Asm`` template string)
-does not know you are using the ebx register.
+does not know you are using the ``ebx`` register.
In such cases you need to supply the ``Clobber`` parameter to ``Asm``,
-to identify the registers that will be used by your assembly code:
+to identify the registers used by your assembly code:
.. code-block:: ada
@@ -626,9 +626,9 @@ to identify the registers that will be used by your assembly code:
Clobber => "ebx");
The Clobber parameter is a static string expression specifying the
-register(s) you are using. Note that register names are *not* prefixed
-by a percent sign. Also, if more than one register is used then their names
-are separated by commas; e.g., ``"eax, ebx"``
+register(s) you are using. Note that register names are *not*
+prefixed by a percent sign. Also, if more than one register is used,
+you separate their names by commas; e.g., ``"eax, ebx"``
The ``Clobber`` parameter has several additional uses:
@@ -648,7 +648,7 @@ unwanted effects. For example, when an ``Asm`` invocation with an input
variable is inside a loop, the compiler might move the loading of the input
variable outside the loop, regarding it as a one-time initialization.
-If this effect is not desired, you can disable such optimizations by setting
+If you don't want this to happen, you can disable such optimizations by setting
the ``Volatile`` parameter to ``True``; for example:
.. code-block:: ada
@@ -664,7 +664,7 @@ By default, ``Volatile`` is set to ``False`` unless there is no
``Outputs`` parameter.
Although setting ``Volatile`` to ``True`` prevents unwanted
-optimizations, it will also disable other optimizations that might be
+optimizations, it also disables other optimizations that might be
important for efficiency. In general, you should set ``Volatile``
to ``True`` only if the compiler's optimizations have created
problems.
@@ -13,7 +13,7 @@ Platform-Specific Information
*****************************
This appendix contains information relating to the implementation
-of run-time libraries on various platforms and also covers topics
+of run-time libraries on various platforms. It also covers topics
related to the GNAT implementation on specific Operating Systems.
.. _`Run_Time_Libraries`:
@@ -87,8 +87,8 @@ Specifying a Run-Time Library
=============================
The :file:`adainclude` subdirectory containing the sources of the GNAT
-run-time library, and the :file:`adalib` subdirectory containing the
-:file:`ALI` files and the static and/or shared GNAT library, are located
+run-time library and the :file:`adalib` subdirectory containing the
+:file:`ALI` files and the static and/or shared GNAT library are located
in the gcc target-dependent area:
@@ -96,7 +96,7 @@ in the gcc target-dependent area:
target=$prefix/lib/gcc/gcc-*dumpmachine*/gcc-*dumpversion*/
-As indicated above, on some platforms several run-time libraries are supplied.
+As indicated above, on some platforms, several run-time libraries are supplied.
These libraries are installed in the target dependent area and
contain a complete source and binary subdirectory. The detailed description
below explains the differences between the different libraries in terms of
@@ -151,8 +151,8 @@ For example on x86-linux:
Run-Time Library Directory Structure
(Upper-case names and dotted/dashed arrows represent soft links)
-If the *rts-sjlj* library is to be selected on a permanent basis,
-these soft links can be modified with the following commands:
+If you want to select the *rts-sjlj* library on a permanent basis,
+you can modify these soft links with the following commands:
::
@@ -165,10 +165,10 @@ Alternatively, you can specify :file:`rts-sjlj/adainclude` in the file
:file:`$target/ada_source_path` and :file:`rts-sjlj/adalib` in
:file:`$target/ada_object_path`.
-.. index:: --RTS option
+.. index:: --RTS switch
-Selecting another run-time library temporarily can be
-achieved by using the :switch:`--RTS` switch, e.g., :switch:`--RTS=sjlj`
+You can select another run-time library temporarily
+by using the :switch:`--RTS` switch, e.g., :switch:`--RTS=sjlj`
.. index:: Linux
@@ -192,14 +192,14 @@ The name of of that package depends on your GNU/Linux distribution:
* RedHat, SUSE: ``glibc-devel``;
* Debian, Ubuntu: ``libc6-dev`` (normally installed by default).
-If using the 32-bit version of GNAT on a 64-bit version of GNU/Linux,
+If you're using the 32-bit version of GNAT on a 64-bit version of GNU/Linux,
you'll need the 32-bit version of the following packages:
* RedHat, SUSE: ``glibc.i686``, ``glibc-devel.i686``, ``ncurses-libs.i686``
* SUSE: ``glibc-locale-base-32bit``
* Debian, Ubuntu: ``libc6:i386``, ``libc6-dev:i386``, ``lib32ncursesw5``
-Other GNU/Linux distributions might be choosing a different name
+Other GNU/Linux distributions might choose different name
for those packages.
@@ -226,9 +226,9 @@ Independent.
If you are not interested in building PIE binaries, you can simply
turn this feature off by first compiling your code with :samp:`-fno-pie`
and then by linking with :samp:`-no-pie` (note the subtle but important
-difference in the names of the options -- the linker option does **not**
-have an `f` after the dash!). When using gprbuild, this is
-achieved by updating the *Required_Switches* attribute in package `Compiler`
+difference in the names of the switches -- the linker switch does **not**
+have an `f` after the dash!). When using gprbuild, you do this
+by updating the *Required_Switches* attribute in package `Compiler`
and, depending on your type of project, either attribute *Switches*
or attribute *Library_Options* in package `Linker`.
@@ -261,7 +261,7 @@ Typically, the default is ``SCHED_OTHER``, while using ``SCHED_FIFO``
or ``SCHED_RR`` requires special (e.g., root) privileges.
.. index:: pragma Time_Slice
-.. index:: -T0 option
+.. index:: -T0 switch
.. index:: pragma Task_Dispatching_Policy
@@ -270,13 +270,13 @@ By default, GNAT uses the ``SCHED_OTHER`` policy. To specify
you can use one of the following:
* ``pragma Time_Slice (0.0)``
-* the corresponding binder option :switch:`-T0`
+* the corresponding binder switch :switch:`-T0`
* ``pragma Task_Dispatching_Policy (FIFO_Within_Priorities)``
To specify ``SCHED_RR``,
you should use ``pragma Time_Slice`` with a
value greater than 0.0, or else use the corresponding :switch:`-T`
-binder option.
+binder switch.
To make sure a program is running as root, you can put something like
this in a library package body in your application:
@@ -288,9 +288,9 @@ this in a library package body in your application:
Ignore : constant Boolean :=
(if geteuid = 0 then True else raise Program_Error with "must be root");
-It gets the effective user id, and if it's not 0 (i.e. root), it raises
-Program_Error. Note that if you re running the code in a container, this may
-not be sufficient, as you may have sufficient priviledge on the container,
+This gets the effective user id and if it's not 0 (i.e. root), it raises
+Program_Error. Note that if you're running the code in a container, this may
+not be sufficient as you may have sufficient privilege on the container,
but not on the host machine running the container, so check that you also
have sufficient priviledge for running the container image.
@@ -302,8 +302,8 @@ A GNU/Linux Debug Quirk
On SuSE 15, some kernels have a defect causing issues when debugging
programs using threads or Ada tasks. Due to the lack of documentation
found regarding this kernel issue, we can only provide limited
-information about which kernels are impacted: kernel version 5.3.18 is
-known to be impacted, and kernels in the 5.14 range or newer are
+information about which kernels are impacted. Kernel version 5.3.18 is
+known to be impacted and kernels in the 5.14 range or newer are
believed to fix this problem.
The bug affects the debugging of 32-bit processes on a 64-bit system.
@@ -328,12 +328,12 @@ platforms.
.. rubric:: Installing from the Command Line
By default the GNAT installers display a GUI that prompts you to enter
- the installation path and similar information, and then guides you through the
- installation process. It is also possible to perform silent installations
+ the installation path and similar information and then guides you through the
+ installation process. You can also perform silent installations
using the command-line interface.
- In order to install one of the GNAT installers from the command
- line you should pass parameter :switch:`/S` (and, optionally,
+ To install one of the GNAT installers from the command
+ line, you should pass parameter :switch:`/S` (and, optionally,
:switch:`/D=<directory>`) as command-line arguments.
For example, for an unattended installation of
@@ -349,7 +349,7 @@ platforms.
You can use the same syntax for all installers.
Note that unattended installations don't modify system path, nor create file
- associations, so such activities need to be done by hand.
+ associations, so you need to do such activities by hand.
.. _Using_GNAT_on_Windows:
@@ -362,7 +362,7 @@ One of the strengths of the GNAT technology is that its tool set
``gdb`` debugger, etc.) is used in the same way regardless of the
platform.
-On Windows this tool set is complemented by a number of Microsoft-specific
+On Windows, this tool set is complemented by a number of Microsoft-specific
tools that have been provided to facilitate interoperability with Windows
when this is required. With these tools:
@@ -373,45 +373,46 @@ when this is required. With these tools:
* You can use any Dynamically Linked Library (DLL) in your Ada code (both
relocatable and non-relocatable DLLs are supported).
-* You can build Ada DLLs for use in other applications. These applications
- can be written in a language other than Ada (e.g., C, C++, etc). Again both
- relocatable and non-relocatable Ada DLLs are supported.
+* You can build Ada DLLs for use in other applications. You can write
+ these applications in a language other than Ada (e.g., C, C++,
+ etc). Again, both relocatable and non-relocatable Ada DLLs are
+ supported.
* You can include Windows resources in your Ada application.
* You can use or create COM/DCOM objects.
-Immediately below are listed all known general GNAT-for-Windows restrictions.
-Other restrictions about specific features like Windows Resources and DLLs
-are listed in separate sections below.
+Listed immediately below are all known general GNAT-for-Windows
+restrictions. We list other restrictions about specific features such
+as Windows Resources and DLLs in separate sections below.
-
-* It is not possible to use ``GetLastError`` and ``SetLastError``
+* You cannot use ``GetLastError`` and ``SetLastError``
when tasking, protected records, or exceptions are used. In these
cases, in order to implement Ada semantics, the GNAT run-time system
calls certain Win32 routines that set the last error variable to 0 upon
- success. It should be possible to use ``GetLastError`` and
+ success. You may be able to use ``GetLastError`` and
``SetLastError`` when tasking, protected record, and exception
features are not used, but it is not guaranteed to work.
-* It is not possible to link against Microsoft C++ libraries except for
- import libraries. Interfacing must be done by the mean of DLLs.
+* You cannot link against Microsoft C++ libraries except for
+ import libraries. You must do interfacing by means of DLLs.
-* It is possible to link against Microsoft C libraries. Yet the preferred
+* You can link against Microsoft C libraries. However, the preferred
solution is to use C/C++ compiler that comes with GNAT, since it
doesn't require having two different development environments and makes the
inter-language debugging experience smoother.
-* When the compilation environment is located on FAT32 drives, users may
- experience recompilations of the source files that have not changed if
+* When the compilation environment is located on FAT32 drives, you may
+ experience recompilations of source files that have not changed if
Daylight Saving Time (DST) state has changed since the last time files
were compiled. NTFS drives do not have this problem.
* No components of the GNAT toolset use any entries in the Windows
- registry. The only entries that can be created are file associations and
- PATH settings, provided the user has chosen to create them at installation
- time, as well as some minimal book-keeping information needed to correctly
- uninstall or integrate different GNAT products.
+ registry. The only entries installation of GNAT may create are file
+ associations and PATH settings, provided you chose to
+ create them at installation time, as well as some minimal
+ bookkeeping information needed to correctly uninstall or integrate
+ different GNAT products.
.. _Using_a_network_installation_of_GNAT:
@@ -436,7 +437,7 @@ make it available:
Be aware that every compilation using the network installation results in the
transfer of large amounts of data across the network and will likely cause
-serious performance penalty.
+a serious performance penalty.
.. _CONSOLE_and_WINDOWS_subsystems:
@@ -448,11 +449,11 @@ CONSOLE and WINDOWS subsystems
.. index:: -mwindows
There are two main subsystems under Windows. The ``CONSOLE`` subsystem
-(which is the default subsystem) will always create a console when
+(which is the default subsystem) always creates a console when
launching the application. This is not something desirable when the
-application has a Windows GUI. To get rid of this console the
-application must be using the ``WINDOWS`` subsystem. To do so
-the :switch:`-mwindows` linker option must be specified.
+application has a Windows GUI. To remove this console, your
+application must use the ``WINDOWS`` subsystem. To do so, you must
+specify the :switch:`-mwindows` linker switch.
::
@@ -465,8 +466,8 @@ Temporary Files
.. index:: Temporary files
-It is possible to control where temporary files gets created by setting
-the :envvar:`TMP` environment variable. The file will be created:
+You can control where temporary files get created by setting the
+:envvar:`TMP` environment variable. The file will be created:
* Under the directory pointed to by the :envvar:`TMP` environment variable if
this directory exists.
@@ -490,7 +491,7 @@ By default, an executable compiled for the Windows platform will do
the following postprocessing on the arguments passed on the command
line:
-* If the argument contains the characters ``*`` and/or ``?``, then
+* If the argument contains the characters ``*`` and/or ``?``,
file expansion will be attempted. For example, if the current directory
contains :file:`a.txt` and :file:`b.txt`, then when calling::
@@ -502,7 +503,7 @@ line:
Ada.Command_Line.Argument (1) -> "a.txt"
Ada.Command_Line.Argument (2) -> "b.txt"
-* Filename expansion can be disabled for a given argument by using single
+* You can disable filename expansion for a given argument by using single
quotes. Thus, calling::
$ my_ada_program '*.txt'
@@ -511,10 +512,10 @@ line:
Ada.Command_Line.Argument (1) -> "*.txt"
-Note that if the program is launched from a shell such as Cygwin Bash
-then quote removal might be performed by the shell.
+Note that if the program is launched from a shell such as Cygwin Bash,
+quote removal might be performed by that shell.
-In some contexts it might be useful to disable this feature (for example if
+In some contexts, it might be useful to disable this feature (for example if
the program performs its own argument expansion). In order to do this, a C
symbol needs to be defined and set to ``0``. You can do this by
adding the following code fragment in one of your Ada units:
@@ -542,13 +543,13 @@ Window's seven standard priority levels by default: Idle, Lowest, Below Normal,
Normal, Above Normal,
When using the ``FIFO_Within_Priorities`` task dispatching policy, GNAT
-will assign the ``REALTIME_PRIORITY_CLASS`` priority class to the application
-and map the Ada priority range to the sixteen priorities made available under
+assigns the ``REALTIME_PRIORITY_CLASS`` priority class to the application
+and maps the Ada priority range to the sixteen priorities made available under
``REALTIME_PRIORITY_CLASS``.
For details on the values of the different priority mappings, see declarations
in :file:`system.ads`. For more information about Windows priorities, please
-refer to Microsoft's documentation.
+refer to Microsoft documentation.
Windows Socket Timeouts
-----------------------
@@ -557,13 +558,13 @@ Microsoft Windows desktops older than ``8.0`` and Microsoft Windows Servers
older than ``2019`` set a socket timeout 500 milliseconds longer than the value
set by setsockopt with ``SO_RCVTIMEO`` and ``SO_SNDTIMEO`` options. The GNAT
runtime makes a correction for the difference in the corresponding Windows
-versions. For Windows Server starting with version ``2019``, the user must
+versions. For Windows Server starting with version ``2019``, you must
provide a manifest file for the GNAT runtime to be able to recognize that
the Windows version does not need the timeout correction. The manifest file
-should be located in the same directory as the executable file, and its file
+should be located in the same directory as the executable file and its file
name must match the executable name suffixed by ``.manifest``. For example,
-if the executable name is :file:`sock_wto.exe`, then the manifest file name
-has to be :file:`sock_wto.exe.manifest`. The manifest file must contain at
+if the executable name is :file:`sock_wto.exe`, the manifest file name
+must be :file:`sock_wto.exe.manifest`. The manifest file must contain at
least the following data::
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
@@ -584,13 +585,15 @@ least the following data::
</compatibility>
</assembly>
-Without the manifest file, the socket timeout is going to be overcorrected on
-these Windows Server versions and the actual time is going to be 500
-milliseconds shorter than what was set with GNAT.Sockets.Set_Socket_Option.
-Note that on Microsoft Windows versions where correction is necessary, there
-is no way to set a socket timeout shorter than 500 ms. If a socket timeout
-shorter than 500 ms is needed on these Windows versions, a call to
-Check_Selector should be added before any socket read or write operations.
+Without the manifest file, the socket timeout will be overcorrected on
+these Windows Server versions and the actual time wil be 500
+milliseconds shorter than what was set with
+``GNAT.Sockets.Set_Socket_Option``. Note that on Microsoft Windows
+versions where correction is necessary, there is no way to set a
+socket timeout shorter than 500 ms. If a socket timeout shorter than
+500 ms is needed on these Windows versions, you should add a call to
+``Check_Selector`` before any socket read or write
+operations.
.. _Mixed-Language_Programming_on_Windows:
@@ -609,20 +612,20 @@ your application, there are no Windows-specific restrictions that
affect the overall interoperability with your Ada code. If you do want
to use the Microsoft tools for your C++ code, you have two choices:
-* Encapsulate your C++ code in a DLL to be linked with your Ada
- application. In this case, use the Microsoft or whatever environment to
+* You can encapsulate your C++ code in a DLL to be linked with your Ada
+ application. In this case, use the Microsoft or other environment to
build the DLL and use GNAT to build your executable
(:ref:`Using_DLLs_with_GNAT`).
-* Or you can encapsulate your Ada code in a DLL to be linked with the
+* You can encapsulate your Ada code in a DLL to be linked with the
other part of your application. In this case, use GNAT to build the DLL
(:ref:`Building_DLLs_with_GNAT_Project_files`) and use the Microsoft
- or whatever environment to build your executable.
+ or other environment to build your executable.
-In addition to the description about C main in
-:ref:`Mixed_Language_Programming` section, if the C main uses a
-stand-alone library it is required on x86-windows to
-setup the SEH context. For this the C main must looks like this:
+In addition to the description about C ``main`` in
+:ref:`Mixed_Language_Programming` section, if the C ``main`` uses a
+stand-alone library, it is required on x86-windows to
+setup the SEH context. For this, the C ``main`` must looks like this:
.. code-block:: c
@@ -649,7 +652,7 @@ setup the SEH context. For this the C main must looks like this:
adafinal();
}
-Note that this is not needed on x86_64-windows where the Windows
+Note that you need not do this on x86_64-windows where the Windows
native SEH support is used.
@@ -661,7 +664,7 @@ Windows Calling Conventions
.. index:: Stdcall
.. index:: APIENTRY
-This section pertain only to Win32. On Win64 there is a single native
+This section pertain only to Win32. On Win64, there is a single native
calling convention. All convention specifiers are ignored on this
platform.
@@ -690,31 +693,31 @@ are available for Windows:
This is the default calling convention used when interfacing to C/C++
routines compiled with either ``gcc`` or Microsoft Visual C++.
-In the ``C`` calling convention subprogram parameters are pushed on the
+In the ``C`` calling convention, subprogram parameters are pushed on the
stack by the caller from right to left. The caller itself is in charge of
cleaning up the stack after the call. In addition, the name of a routine
with ``C`` calling convention is mangled by adding a leading underscore.
The name to use on the Ada side when importing (or exporting) a routine
with ``C`` calling convention is the name of the routine. For
-instance the C function:
+example you should import the C function:
::
int get_val (long);
-should be imported from Ada as follows:
+from Ada as follows:
.. code-block:: ada
function Get_Val (V : Interfaces.C.long) return Interfaces.C.int;
pragma Import (C, Get_Val, External_Name => "get_val");
-Note that in this particular case the ``External_Name`` parameter could
-have been omitted since, when missing, this parameter is taken to be the
-name of the Ada entity in lower case. When the ``Link_Name`` parameter
-is missing, as in the above example, this parameter is set to be the
-``External_Name`` with a leading underscore.
+Note that in this particular case, you could have omitted the
+``External_Name`` parameter since, when missing, this parameter is set
+to the name of the Ada entity in lower case. When the ``Link_Name``
+parameter is missing, as in the above example, this parameter is set
+the ``External_Name`` with a leading underscore.
When importing a variable defined in C, you should always use the ``C``
calling convention unless the object containing the variable is part of a
@@ -729,12 +732,12 @@ convention, :ref:`Stdcall_Calling_Convention`).
This convention, which was the calling convention used for Pascal
programs, is used by Microsoft for all the routines in the Win32 API for
-efficiency reasons. It must be used to import any routine for which this
+efficiency reasons. You must use it to import any routine for which this
convention was specified.
-In the ``Stdcall`` calling convention subprogram parameters are pushed
-on the stack by the caller from right to left. The callee (and not the
-caller) is in charge of cleaning the stack on routine exit. In addition,
+In the ``Stdcall`` calling convention, subprogram parameters are also pushed
+on the stack by the caller from right to left. However, the callee, not the
+caller, is in charge of cleaning up the stack on routine exit. In addition,
the name of a routine with ``Stdcall`` calling convention is mangled by
adding a leading underscore (as for the ``C`` calling convention) and a
trailing :samp:`@{nn}`, where ``nn`` is the overall size (in
@@ -743,13 +746,13 @@ bytes) of the parameters passed to the routine.
The name to use on the Ada side when importing a C routine with a
``Stdcall`` calling convention is the name of the C routine. The leading
underscore and trailing :samp:`@{nn}` are added automatically by
-the compiler. For instance the Win32 function:
+the compiler. For example, you could import the Win32 function:
::
APIENTRY int get_val (long);
-should be imported from Ada as follows:
+from Ada as follows:
.. code-block:: ada
@@ -757,17 +760,18 @@ should be imported from Ada as follows:
pragma Import (Stdcall, Get_Val);
-- On the x86 a long is 4 bytes, so the Link_Name is "_get_val@4"
-As for the ``C`` calling convention, when the ``External_Name``
-parameter is missing, it is taken to be the name of the Ada entity in lower
-case. If instead of writing the above import pragma you write:
+Like the case for the ``C`` calling convention, when the
+``External_Name`` parameter is missing, it is the name of the Ada
+entity in lower case. If instead of writing the above import pragma
+you write:
.. code-block:: ada
function Get_Val (V : Interfaces.C.long) return Interfaces.C.int;
pragma Import (Stdcall, Get_Val, External_Name => "retrieve_val");
-then the imported routine is ``_retrieve_val@4``. However, if instead
-of specifying the ``External_Name`` parameter you specify the
+the imported routine is ``_retrieve_val@4``. However, if instead
+of specifying the ``External_Name`` parameter, you specify the
``Link_Name`` as in the following example:
.. code-block:: ada
@@ -775,15 +779,15 @@ of specifying the ``External_Name`` parameter you specify the
function Get_Val (V : Interfaces.C.long) return Interfaces.C.int;
pragma Import (Stdcall, Get_Val, Link_Name => "retrieve_val");
-then the imported routine is ``retrieve_val``, that is, there is no
-decoration at all. No leading underscore and no Stdcall suffix
+the imported routine is ``retrieve_val``. There is no
+decoration at all; no leading underscore and no Stdcall suffix
:samp:`@{nn}`.
This is especially important as in some special cases a DLL's entry
point name lacks a trailing :samp:`@{nn}` while the exported
name generated for a call has it.
-It is also possible to import variables defined in a DLL by using an
+You can also import variables defined in a DLL by using an
import pragma for a variable. As an example, if a DLL contains a
variable defined as:
@@ -798,7 +802,7 @@ then, to access this variable from Ada you should write:
My_Var : Interfaces.C.int;
pragma Import (Stdcall, My_Var);
-Note that to ease building cross-platform bindings this convention
+Note that to ease building cross-platform bindings, this convention
will be handled as a ``C`` calling convention on non-Windows platforms.
@@ -807,7 +811,7 @@ will be handled as a ``C`` calling convention on non-Windows platforms.
``Win32`` Calling Convention
""""""""""""""""""""""""""""
-This convention, which is GNAT-specific is fully equivalent to the
+This convention, which is GNAT-specific, is fully equivalent to the
``Stdcall`` calling convention described above.
@@ -816,7 +820,7 @@ This convention, which is GNAT-specific is fully equivalent to the
``DLL`` Calling Convention
""""""""""""""""""""""""""
-This convention, which is GNAT-specific is fully equivalent to the
+This convention, which is GNAT-specific, is fully equivalent to the
``Stdcall`` calling convention described above.
@@ -838,10 +842,10 @@ slower since, as you will understand below, such calls are indirect.
To illustrate the remainder of this section, suppose that an application
wants to use the services of a DLL :file:`API.dll`. To use the services
-provided by :file:`API.dll` you must statically link against the DLL or
+provided by :file:`API.dll`, you must statically link against the DLL or
an import library which contains a jump table with an entry for each
-routine and variable exported by the DLL. In the Microsoft world this
-import library is called :file:`API.lib`. When using GNAT this import
+routine and variable exported by the DLL. In the Microsoft world, this
+import library is called :file:`API.lib`. When using GNAT, this import
library is called either :file:`libAPI.dll.a`, :file:`libapi.dll.a`,
:file:`libAPI.a` or :file:`libapi.a` (names are case insensitive).
@@ -853,11 +857,11 @@ and you run your application, here is what happens:
* The DLL :file:`API.dll` is mapped into the address space of your
application. This means that:
- - The DLL will use the stack of the calling thread.
+ - The DLL uses the stack of the calling thread.
- - The DLL will use the virtual address space of the calling process.
+ - The DLL uses the virtual address space of the calling process.
- - The DLL will allocate memory from the virtual address space of the calling
+ - The DLL allocates memory from the virtual address space of the calling
process.
- Handles (pointers) can be safely exchanged between routines in the DLL
@@ -874,19 +878,19 @@ and you run your application, here is what happens:
variables exported by the DLL.
There is an additional point which is worth mentioning. In the Windows
-world there are two kind of DLLs: relocatable and non-relocatable
-DLLs. Non-relocatable DLLs can only be loaded at a very specific address
+world, there are two kind of DLLs: relocatable and non-relocatable
+DLLs. Non-relocatable DLLs can only be loaded at a specific address
in the target application address space. If the addresses of two
non-relocatable DLLs overlap and these happen to be used by the same
-application, a conflict will occur and the application will run
-incorrectly. Hence, when possible, it is always preferable to use and
+application, a conflict occurs and the application will run
+incorrectly. Hence, when possible, you should always use and
build relocatable DLLs. Both relocatable and non-relocatable DLLs are
-supported by GNAT. Note that the :switch:`-s` linker option (see GNU Linker
-User's Guide) removes the debugging symbols from the DLL but the DLL can
+supported by GNAT. Note that the :switch:`-s` linker switch (see GNU Linker
+User's Guide) removes the debugging symbols from the DLL, but the DLL can
still be relocated.
As a side note, an interesting difference between Microsoft DLLs and
-Unix shared libraries, is the fact that on most Unix systems all public
+Unix shared libraries is the fact that on most Unix systems all public
routines are exported by default in a Unix shared library, while under
Windows it is possible (but not required) to list exported routines in
a definition file (see :ref:`The Definition File <The_Definition_File>`).
@@ -901,12 +905,12 @@ To use the services of a DLL, say :file:`API.dll`, in your Ada application
you must have:
* The Ada spec for the routines and/or variables you want to access in
- :file:`API.dll`. If not available this Ada spec must be built from the C/C++
- header files provided with the DLL.
+ :file:`API.dll`. If not available, you must build this Ada spec from the
+ C/C++ header files provided with the DLL.
* The import library (:file:`libAPI.dll.a` or :file:`API.lib`). As previously
- mentioned an import library is a statically linked library containing the
- import table which will be filled at load time to point to the actual
+ mentioned, an import library is a statically linked library containing the
+ import table, which is filled at load time to point to the actual
:file:`API.dll` routines. Sometimes you don't have an import library for the
DLL you want to use. The following sections will explain how to build
one. Note that this is optional.
@@ -932,8 +936,8 @@ look for a library name in this specific order:
* :file:`libAPI.dll`
* :file:`API.dll`
-The first three are the GNU style import libraries. The third is the
-Microsoft style import libraries. The last two are the actual DLL names.
+The first three are the GNU-style import libraries. The third is the
+Microsoft-style import libraries. The last two are the actual DLL names.
Note that if the Ada package spec for :file:`API.dll` contains the
following pragma
@@ -945,7 +949,7 @@ following pragma
you do not have to add :switch:`-largs -lAPI` at the end of the
``gnatmake`` command.
-If any one of the items above is missing you will have to create it
+If any one of the items above is missing, you will have to create it
yourself. The following sections explain how to do so using as an
example a fictitious DLL called :file:`API.dll`.
@@ -959,7 +963,7 @@ A DLL typically comes with a C/C++ header file which provides the
definitions of the routines and variables exported by the DLL. The Ada
equivalent of this header file is a package spec that contains definitions
for the imported entities. If the DLL you intend to use does not come with
-an Ada spec you have to generate one such spec yourself. For example if
+an Ada spec, you have to generate such a spec yourself. For example, if
the header file of :file:`API.dll` is a file :file:`api.h` containing the
following two definitions:
@@ -1032,7 +1036,7 @@ suffix) has the following structure:
*EXPORTS*
This section gives the list of exported symbols (procedures, functions or
- variables). For instance in the case of :file:`API.dll` the ``EXPORTS``
+ variables). For example, in the case of :file:`API.dll` the ``EXPORTS``
section of :file:`API.def` looks like:
::
@@ -1055,7 +1059,7 @@ sections are not relevant to the discussion at hand.
You can automatically create the definition file :file:`API.def`
(see :ref:`The Definition File <The_Definition_File>`) from a DLL.
-For that use the ``dlltool`` program as follows:
+To do that, use the ``dlltool`` program as follows:
::
@@ -1063,21 +1067,22 @@ For that use the ``dlltool`` program as follows:
Note that if some routines in the DLL have the ``Stdcall`` convention
(:ref:`Windows_Calling_Conventions`) with stripped :samp:`@{nn}`
- suffix then you'll have to edit :file:`api.def` to add it, and specify
+ suffix then you'll have to edit :file:`api.def` to add it and specify
:switch:`-k` to ``gnatdll`` when creating the import library.
Here are some hints to find the right :samp:`@{nn}` suffix.
- - If you have the Microsoft import library (.lib), it is possible to get
- the right symbols by using Microsoft ``dumpbin`` tool (see the
- corresponding Microsoft documentation for further details).
+ - If you have the Microsoft import library (.lib), you may be able
+ to find the right symbols by using the Microsoft ``dumpbin`` tool
+ (see the corresponding Microsoft documentation for further
+ details).
::
$ dumpbin /exports api.lib
- - If you have a message about a missing symbol at link time the compiler
- tells you what symbol is expected. You just have to go back to the
+ - If you get a message about a missing symbol at link time, the compiler
+ tells you what symbol is expected. You then can go back to the
definition file and add the right suffix.
@@ -1085,8 +1090,8 @@ For that use the ``dlltool`` program as follows:
.. rubric:: GNAT-Style Import Library
-To create a static import library from :file:`API.dll` with the GNAT tools
-you should create the .def file, then use ``gnatdll`` tool
+To create a static import library from :file:`API.dll` with the GNAT tools,
+you should create the :file:`.def` file and use the ``gnatdll`` tool
(see :ref:`Using_gnatdll`) as follows:
::
@@ -1098,7 +1103,7 @@ you should create the .def file, then use ``gnatdll`` tool
:file:`API.dll`. The name of the static import library generated is
computed from the name of the definition file as follows: if the
definition file name is :file:`xyz.def`, the import library name will
- be :file:`libxyz.a`. Note that in the previous example option
+ be :file:`libxyz.a`. Note that in the previous example, the switch
:switch:`-e` could have been removed because the name of the definition
file (before the ``.def`` suffix) is the same as the name of the
DLL (:ref:`Using_gnatdll` for more information about ``gnatdll``).
@@ -1113,14 +1118,14 @@ Ada DLL available to applications developed with Microsoft
tools (:ref:`Mixed-Language_Programming_on_Windows`).
To create a Microsoft-style import library for :file:`API.dll` you
-should create the .def file, then build the actual import library using
+should create the :file:`.def` file, then build the actual import library using
Microsoft's ``lib`` utility:
::
$ lib -machine:IX86 -def:API.def -out:API.lib
- If you use the above command the definition file :file:`API.def` must
+ If you use the above command, the definition file :file:`API.def` must
contain a line giving the name of the DLL:
::
@@ -1142,9 +1147,9 @@ There is nothing specific to Windows in the build process.
See the *Library Projects* section in the *GNAT Project Manager*
chapter of the *GPRbuild User's Guide*.
-Due to a system limitation, it is not possible under Windows to create threads
+Due to a system limitation, you cannot create threads under Windows
when inside the ``DllMain`` routine which is used for auto-initialization
-of shared libraries, so it is not possible to have library level tasks in SALs.
+of shared libraries, so you can't have library level tasks in SALs.
.. _Building_DLLs_with_GNAT:
@@ -1154,25 +1159,25 @@ Building DLLs with GNAT
.. index:: DLLs, building
-This section explain how to build DLLs using the GNAT built-in DLL
-support. With the following procedure it is straight forward to build
+This section explains how to build DLLs using the GNAT built-in DLL
+support. With the following procedure, it is straightforward to build
and use DLLs with GNAT.
* Building object files.
The first step is to build all objects files that are to be included
- into the DLL. This is done by using the standard ``gnatmake`` tool.
+ into the DLL. This is done using the standard ``gnatmake`` tool.
* Building the DLL.
- To build the DLL you must use the ``gcc`` :switch:`-shared` and
- :switch:`-shared-libgcc` options. It is quite simple to use this method:
+ To build the DLL, you must use the ``gcc`` :switch:`-shared` and
+ :switch:`-shared-libgcc` switches. It's quite simple to use this method:
::
$ gcc -shared -shared-libgcc -o api.dll obj1.o obj2.o ...
- It is important to note that in this case all symbols found in the
- object files are automatically exported. It is possible to restrict
+ It's important to note that in this case all symbols found in the
+ object files are automatically exported. You can restrict
the set of symbols to export by passing to ``gcc`` a definition
file (see :ref:`The Definition File <The_Definition_File>`).
For example:
@@ -1181,15 +1186,15 @@ and use DLLs with GNAT.
$ gcc -shared -shared-libgcc -o api.dll api.def obj1.o obj2.o ...
- If you use a definition file you must export the elaboration procedures
- for every package that required one. Elaboration procedures are named
+ If you use a definition file, you must export the elaboration procedures
+ for every package that requires one. Elaboration procedures are named
using the package name followed by "_E".
* Preparing DLL to be used.
- For the DLL to be used by client programs the bodies must be hidden
- from it and the .ali set with read-only attribute. This is very important
- otherwise GNAT will recompile all packages and will not actually use
- the code in the DLL. For example:
+ For the DLL to be used by client programs, the bodies must be hidden
+ from it and the :file:`.ali` set with read-only attribute. This is very
+ important because otherwise GNAT will recompile all packages and will not
+ actually use the code in the DLL. For example:
::
@@ -1197,10 +1202,10 @@ and use DLLs with GNAT.
$ copy *.ads *.ali api.dll apilib
$ attrib +R apilib\\*.ali
-At this point it is possible to use the DLL by directly linking
+At this point, you can use the DLL by directly linking
against it. Note that you must use the GNAT shared runtime when using
-GNAT shared libraries. This is achieved by using the :switch:`-shared` binder
-option.
+GNAT shared libraries. You do this with the :switch:`-shared` binder
+switch.
::
@@ -1216,7 +1221,7 @@ Building DLLs with gnatdll
Note that it is preferred to use GNAT Project files
(:ref:`Building_DLLs_with_GNAT_Project_files`) or the built-in GNAT
-DLL support (:ref:`Building_DLLs_with_GNAT`) or to build DLLs.
+DLL support (:ref:`Building_DLLs_with_GNAT`) to build DLLs.
This section explains how to build DLLs containing Ada code using
``gnatdll``. These DLLs will be referred to as Ada DLLs in the
@@ -1232,13 +1237,13 @@ non-Ada applications are as follows:
skip this step if you plan to use the Ada DLL only from Ada applications.
* Your Ada code must export an initialization routine which calls the routine
- ``adainit`` generated by ``gnatbind`` to perform the elaboration of
+ ``adainit`` (generated by ``gnatbind``) to perform the elaboration of
the Ada code in the DLL (:ref:`Ada_DLLs_and_Elaboration`). The initialization
routine exported by the Ada DLL must be invoked by the clients of the DLL
to initialize the DLL.
* When useful, the DLL should also export a finalization routine which calls
- routine ``adafinal`` generated by ``gnatbind`` to perform the
+ routine ``adafinal`` (also generated by ``gnatbind``) to perform the
finalization of the Ada code in the DLL (:ref:`Ada_DLLs_and_Finalization`).
The finalization routine exported by the Ada DLL must be invoked by the
clients of the DLL when the DLL services are no further needed.
@@ -1249,12 +1254,12 @@ non-Ada applications are as follows:
* You must provide a definition file listing the exported entities
(:ref:`The Definition File <The_Definition_File>`).
-* Finally you must use ``gnatdll`` to produce the DLL and the import
+* Finally, you must use ``gnatdll`` to produce the DLL and the import
library (:ref:`Using_gnatdll`).
Note that a relocatable DLL stripped using the ``strip``
-binutils tool will not be relocatable anymore. To build a DLL without
-debug information pass :switch:`-largs -s` to ``gnatdll``. This
+binutils tool is no longer relocatable. To build a DLL without
+debug information, pass :switch:`-largs -s` to ``gnatdll``. This
restriction does not apply to a DLL built using a Library Project.
See the *Library Projects* section in the *GNAT Project Manager*
chapter of the *GPRbuild User's Guide*.
@@ -1265,11 +1270,11 @@ chapter of the *GPRbuild User's Guide*.
Limitations When Using Ada DLLs from Ada
""""""""""""""""""""""""""""""""""""""""
-When using Ada DLLs from Ada applications there is a limitation users
-should be aware of. Because on Windows the GNAT run-time is not in a DLL of
-its own, each Ada DLL includes a part of the GNAT run-time. Specifically,
+When using Ada DLLs from Ada applications there is a limitation you
+should be aware of. On Windows, the GNAT run-time is not in a DLL of
+its own, so each Ada DLL includes a part of the GNAT run-time. Specifically,
each Ada DLL includes the services of the GNAT run-time that are necessary
-to the Ada code inside the DLL. As a result, when an Ada program uses an
+for the Ada code inside the DLL. As a result, when an Ada program uses an
Ada DLL there are two independent GNAT run-times: one in the Ada DLL and
one in the main program.
@@ -1342,7 +1347,7 @@ variable:
end Finalize_API;
end API;
-If the Ada DLL you are building will only be used by Ada applications
+If the Ada DLL you are building will only be used by Ada applications,
you do not have to export Ada entities with a ``C`` or ``Stdcall``
convention. As an example, the previous package could be written as
follows:
@@ -1376,7 +1381,7 @@ follows:
end API;
Note that if you do not export the Ada entities with a ``C`` or
-``Stdcall`` convention you will have to provide the mangled Ada names
+``Stdcall`` convention, you will have to provide the mangled Ada names
in the definition file of the Ada DLL
(:ref:`Creating_the_Definition_File`).
@@ -1393,7 +1398,7 @@ routines in the Ada library that are needed by it. The first thing a
user of your DLL must do is elaborate the Ada code
(:ref:`Elaboration_Order_Handling_in_GNAT`).
-To achieve this you must export an initialization routine
+To allow this, you must export an initialization routine
(``Initialize_API`` in the previous example), which must be invoked
before using any of the DLL services. This elaboration routine must call
the Ada elaboration routine ``adainit`` generated by the GNAT binder
@@ -1403,13 +1408,13 @@ automatically invoked during the DLL build process by the ``gnatdll``
tool (:ref:`Using_gnatdll`).
When a DLL is loaded, Windows systematically invokes a routine called
-``DllMain``. It would therefore be possible to call ``adainit``
+``DllMain``. It should therefore be possible to call ``adainit``
directly from ``DllMain`` without having to provide an explicit
-initialization routine. Unfortunately, it is not possible to call
+initialization routine. Unfortunately, you can't call
``adainit`` from the ``DllMain`` if your program has library level
tasks because access to the ``DllMain`` entry point is serialized by
the system (that is, only a single thread can execute 'through' it at a
-time), which means that the GNAT run-time will deadlock waiting for the
+time), which means that the GNAT run-time will deadlock waiting for a
newly created task to complete its initialization.
@@ -1454,7 +1459,7 @@ contained in the DLL: one for building the DLL and the other for using
the DLL. This is because the ``DLL`` calling convention is needed to
use a variable defined in a DLL, but when building the DLL, the variable
must have either the ``Ada`` or ``C`` calling convention. As an
-example consider a DLL comprising the following package ``API``:
+example consider a DLL consisting of the following package ``API``:
.. code-block:: ada
@@ -1481,9 +1486,9 @@ DLL is:
Creating the Definition File
""""""""""""""""""""""""""""
-The definition file is the last file needed to build the DLL. It lists
+The definition file is the last file you need to build the DLL. It lists
the exported symbols. As an example, the definition file for a DLL
-containing only package ``API`` (where all the entities are exported
+containing only package ``API`` above (where all the entities are exported
with a ``C`` calling convention) is:
::
@@ -1495,7 +1500,7 @@ with a ``C`` calling convention) is:
initialize_api
If the ``C`` calling convention is missing from package ``API``,
-then the definition file contains the mangled Ada names of the above
+the definition file contains the mangled Ada names of the above
entities, which in this case are:
::
@@ -1516,9 +1521,9 @@ Using ``gnatdll``
``gnatdll`` is a tool to automate the DLL build process once all the Ada
and non-Ada sources that make up your DLL have been compiled.
-``gnatdll`` is actually in charge of two distinct tasks: build the
-static import library for the DLL and the actual DLL. The form of the
-``gnatdll`` command is
+``gnatdll`` is actually in charge of two distinct tasks: building both the
+static import library for the DLL and the actual DLL. You invoke the
+``gnatdll`` command as
::
@@ -1537,10 +1542,10 @@ You may specify any of the following switches to ``gnatdll``:
.. index:: -a (gnatdll)
:switch:`-a[{address}]`
- Build a non-relocatable DLL at ``address``. If ``address`` is not
- specified the default address ``0x11000000`` will be used. By default,
- when this switch is missing, ``gnatdll`` builds relocatable DLL. We
- advise the reader to build relocatable DLL.
+ Build a non-relocatable DLL at ``address``. If you don't specify
+ ``address``, ``gnatdll`` uses the default address of ``0x11000000``. By
+ default, when this switch is missing, ``gnatdll`` builds a
+ relocatable DLL. We advise you to build relocatable DLL.
.. index:: -b (gnatdll)
@@ -1553,18 +1558,18 @@ You may specify any of the following switches to ``gnatdll``:
.. index:: -bargs (gnatdll)
:switch:`-bargs {opts}`
- Binder options. Pass ``opts`` to the binder.
+ Binder switches. Pass ``opts`` to the binder.
.. index:: -d (gnatdll)
:switch:`-d {dllfile}`
- ``dllfile`` is the name of the DLL. This switch must be present for
- ``gnatdll`` to do anything. The name of the generated import library is
- obtained algorithmically from ``dllfile`` as shown in the following
+ ``dllfile`` is the name of the DLL. You must specify this switch for
+ ``gnatdll`` to do anything. ``gnatdll`` names the generated import library
+ algorithmically from ``dllfile`` as shown in the following
example: if ``dllfile`` is :file:`xyz.dll`, the import library name is
- :file:`libxyz.dll.a`. The name of the definition file to use (if not specified
- by option :switch:`-e`) is obtained algorithmically from ``dllfile``
+ :file:`libxyz.dll.a`. ``gnatdll`` obtains the name of the definition file (if not specified
+ by switch :switch:`-e`) algorithmically from ``dllfile``
as shown in the following example:
if ``dllfile`` is :file:`xyz.dll`, the definition
file used is :file:`xyz.def`.
@@ -1605,10 +1610,10 @@ You may specify any of the following switches to ``gnatdll``:
:switch:`-k`
Removes the :samp:`@{nn}` suffix from the import library's exported
names, but keeps them for the link names. You must specify this
- option if you want to use a ``Stdcall`` function in a DLL for which
+ switch if you want to use a ``Stdcall`` function in a DLL for which
the :samp:`@{nn}` suffix has been removed. This is the case for most
- of the Windows NT DLL for example. This option has no effect when
- :switch:`-n` option is specified.
+ of the Windows NT DLL for example. This switch has no effect if you
+ specify the :switch:`-n` switch.
.. index:: -l (gnatdll)
@@ -1640,12 +1645,12 @@ You may specify any of the following switches to ``gnatdll``:
.. index:: -largs (gnatdll)
:switch:`-largs {opts}`
- Linker options. Pass ``opts`` to the linker.
+ Linker switches. Pass ``opts`` to the linker.
.. rubric:: ``gnatdll`` Example
-As an example the command to build a relocatable DLL from :file:`api.adb`
+As an example, the command to build a relocatable DLL from :file:`api.adb`
once :file:`api.adb` has been compiled and :file:`api.def` created is
::
@@ -1660,7 +1665,7 @@ only the DLL, just type:
$ gnatdll -d api.dll -n api.ali
-Alternatively if you want to create just the import library, type:
+Alternatively, if you want to create just the import library, type:
::
@@ -1675,12 +1680,12 @@ goes on behind the scenes, you should skip this section.
We use the previous example of a DLL containing the Ada package ``API``,
to illustrate the steps necessary to build a DLL. The starting point is a
-set of objects that will make up the DLL and the corresponding ALI
-files. In the case of this example this means that :file:`api.o` and
-:file:`api.ali` are available. To build a relocatable DLL, ``gnatdll`` does
+set of objects that make up the DLL and the corresponding ALI
+files. In the case of this example, this means :file:`api.o` and
+:file:`api.ali`. To build a relocatable DLL, ``gnatdll`` does
the following:
-* ``gnatdll`` builds the base file (:file:`api.base`). A base file gives
+* builds the base file (:file:`api.base`). A base file gives
the information necessary to generate relocation information for the
DLL.
@@ -1690,12 +1695,12 @@ the following:
$ gnatlink api -o api.jnk -mdll -Wl,--base-file,api.base
In addition to the base file, the ``gnatlink`` command generates an
- output file :file:`api.jnk` which can be discarded. The :switch:`-mdll` switch
+ output file :file:`api.jnk`, which can be discarded. The :switch:`-mdll` switch
asks ``gnatlink`` to generate the routines ``DllMain`` and
``DllMainCRTStartup`` that are called by the Windows loader when the DLL
is loaded into memory.
-* ``gnatdll`` uses ``dlltool`` (see :ref:`Using dlltool <Using_dlltool>`) to build the
+* uses ``dlltool`` (see :ref:`Using dlltool <Using_dlltool>`) to build the
export table (:file:`api.exp`). The export table contains the relocation
information in a form which can be used during the final link to ensure
that the Windows loader is able to place the DLL anywhere in memory.
@@ -1705,7 +1710,7 @@ the following:
$ dlltool --dllname api.dll --def api.def --base-file api.base \\
--output-exp api.exp
-* ``gnatdll`` builds the base file using the new export table. Note that
+* builds the base file using the new export table. Note that
``gnatbind`` must be called once again since the binder generated file
has been deleted during the previous call to ``gnatlink``.
@@ -1716,7 +1721,7 @@ the following:
-Wl,--base-file,api.base
-* ``gnatdll`` builds the new export table using the new base file and
+* builds the new export table using the new base file and
generates the DLL import library :file:`libAPI.dll.a`.
@@ -1725,8 +1730,7 @@ the following:
$ dlltool --dllname api.dll --def api.def --base-file api.base \\
--output-exp api.exp --output-lib libAPI.a
-* Finally ``gnatdll`` builds the relocatable DLL using the final export
- table.
+* Finally, builds the relocatable DLL using the final export table.
::
@@ -1740,8 +1744,7 @@ the following:
``dlltool`` is the low-level tool used by ``gnatdll`` to build
DLLs and static import libraries. This section summarizes the most
-common ``dlltool`` switches. The form of the ``dlltool`` command
-is
+common ``dlltool`` switches. You run ``dlltool`` as follows:
::
@@ -1753,8 +1756,8 @@ is
.. index:: --base-file (dlltool)
:switch:`--base-file {basefile}`
- Read the base file ``basefile`` generated by the linker. This switch
- is used to create a relocatable DLL.
+ Read the base file ``basefile`` generated by the linker. You use this switch
+ to create a relocatable DLL.
.. index:: --def (dlltool)
@@ -1766,7 +1769,7 @@ is
.. index:: --dllname (dlltool)
:switch:`--dllname {name}`
- Gives the name of the DLL. This switch is used to embed the name of the
+ Gives the name of the DLL. You use this switch to embed the name of the
DLL in the static import library generated by ``dlltool`` with switch
:switch:`--output-lib`.
@@ -1817,8 +1820,8 @@ GNAT and Windows Resources
.. index:: Resources, windows
-Resources are an easy way to add Windows specific objects to your
-application. The objects that can be added as resources include:
+Resources are an easy way to add Windows-specific objects to your
+application. The objects that you can add as resources include:
* menus
@@ -1838,13 +1841,10 @@ application. The objects that can be added as resources include:
* version information
-For example, a version information resource can be defined as follow and
-embedded into an executable or DLL:
-
-A version information resource can be used to embed information into an
-executable or a DLL. These information can be viewed using the file properties
-from the Windows Explorer. Here is an example of a version information
-resource:
+You can use a version information resource to embed information into
+an executable or a DLL. This information can be viewed using the file
+properties from the Windows Explorer. Here's an example of a version
+information resource:
::
@@ -1878,7 +1878,7 @@ The value ``0809`` (langID) is for the U.K English language and
multilingual.
This section explains how to build, compile and use resources. Note that this
-section does not cover all resource objects, for a complete description see
+section does not cover all resource objects; for a complete description see
the corresponding Microsoft documentation.
@@ -1889,17 +1889,17 @@ Building Resources
.. index:: Resources, building
-A resource file is an ASCII file. By convention resource files have an
+A resource file is an ASCII file. By convention, resource files have an
:file:`.rc` extension.
The easiest way to build a resource file is to use Microsoft tools
such as ``imagedit.exe`` to build bitmaps, icons and cursors and
``dlgedit.exe`` to build dialogs.
-It is always possible to build an :file:`.rc` file yourself by writing a
+You can always build an :file:`.rc` file yourself by writing a
resource script.
-It is not our objective to explain how to write a resource file. A
-complete description of the resource script language can be found in the
-Microsoft documentation.
+It's not our objective to explain how to write a resource file. A
+complete description of the resource script language can be found in
+the Microsoft documentation.
.. _Compiling_Resources:
@@ -1911,23 +1911,23 @@ Compiling Resources
.. index:: windres
.. index:: Resources, compiling
-This section describes how to build a GNAT-compatible (COFF) object file
-containing the resources. This is done using the Resource Compiler
+This section describes how you can build a GNAT-compatible (COFF) object file
+containing the resources. You do this using the Resource Compiler
``windres`` as follows:
::
$ windres -i myres.rc -o myres.o
-By default ``windres`` will run ``gcc`` to preprocess the :file:`.rc`
+By default ``windres`` runs ``gcc`` to preprocess the :file:`.rc`
file. You can specify an alternate preprocessor (usually named
:file:`cpp.exe`) using the ``windres`` :switch:`--preprocessor`
-parameter. A list of all possible options may be obtained by entering
+parameter. You can obtain a list of all possible switches by entering
the command ``windres`` :switch:`--help`.
-It is also possible to use the Microsoft resource compiler ``rc.exe``
+You can also use the Microsoft resource compiler ``rc.exe``
to produce a :file:`.res` file (binary resource file). See the
-corresponding Microsoft documentation for further details. In this case
+corresponding Microsoft documentation for further details. In this case,
you need to use ``windres`` to translate the :file:`.res` file to a
GNAT-compatible object file as follows:
@@ -1945,8 +1945,8 @@ Using Resources
To include the resource file in your program just add the
GNAT-compatible object file for the resource(s) to the linker
-arguments. With ``gnatmake`` this is done by using the :switch:`-largs`
-option:
+arguments. With ``gnatmake`` you do this using the :switch:`-largs`
+switch:
::
@@ -1960,11 +1960,12 @@ Using GNAT DLLs from Microsoft Visual Studio Applications
.. index:: Microsoft Visual Studio, use with GNAT DLLs
-This section describes a common case of mixed GNAT/Microsoft Visual Studio
-application development, where the main program is developed using MSVS, and
-is linked with a DLL developed using GNAT. Such a mixed application should
-be developed following the general guidelines outlined above; below is the
-cookbook-style sequence of steps to follow:
+This section describes a common case of mixed GNAT/Microsoft Visual
+Studio application development, where the main program is developed
+using MSVS and is linked with a DLL developed using GNAT. You should
+develop such a mixed application following the general guidelines
+outlined above; below is the cookbook-style sequence of steps to
+follow:
1. First develop and build the GNAT shared library using a library project
(let's assume the project is :file:`mylib.gpr`, producing the library :file:`libmylib.dll`):
@@ -1973,9 +1974,10 @@ cookbook-style sequence of steps to follow:
$ gprbuild -p mylib.gpr
-2. Produce a .def file for the symbols you need to interface with, either by
- hand or automatically with possibly some manual adjustments
- (see :ref:`Creating Definition File Automatically <Create_Def_File_Automatically>`):
+2. Produce a :file:`.def` file for the symbols you need to interface
+ with, either by hand or automatically with possibly some manual
+ adjustments (see :ref:`Creating Definition File Automatically
+ <Create_Def_File_Automatically>`):
::
@@ -1995,14 +1997,15 @@ If you are using a 64-bit toolchain, the above becomes...
$ lib -machine:X64 -def:libmylib.def -out:libmylib.lib
-5. Build the C main
+5. Build the C ``main``:
::
$ cl /O2 /MD main.c libmylib.lib
-6. Before running the executable, make sure you have set the PATH to the DLL,
- or copy the DLL into into the directory containing the .exe.
+6. Before running the executable, make sure you have set the PATH to
+ include the DLL or copy the DLL into into the directory containing
+ the :file:`.exe`.
.. _Debugging_a_DLL:
@@ -2012,21 +2015,20 @@ Debugging a DLL
.. index:: DLL debugging
-Debugging a DLL is similar to debugging a standard program. But
-we have to deal with two different executable parts: the DLL and the
-program that uses it. We have the following four possibilities:
+Debugging a DLL is similar to debugging a standard program, but
+you have to deal with two different executable parts: the DLL and the
+program that uses it. There are the following four possibilities:
-* The program and the DLL are built with GCC/GNAT.
+* The program and DLL are built with GCC/GNAT.
* The program is built with foreign tools and the DLL is built with
GCC/GNAT.
* The program is built with GCC/GNAT and the DLL is built with
foreign tools.
-In this section we address only cases one and two above.
-There is no point in trying to debug
-a DLL with GNU/GDB, if there is no GDB-compatible debugging
-information in it. To do so you must use a debugger compatible with the
-tools suite used to build the DLL.
+In this section we address only cases one and two above. Note that
+there is no point in trying to debug a DLL with GNU/GDB if there is no
+GDB-compatible debugging information in it. To do so, you must use a
+debugger compatible with the tools suite used to build the DLL.
.. _Program_and_DLL_Both_Built_with_GCC/GNAT:
@@ -2034,14 +2036,14 @@ Program and DLL Both Built with GCC/GNAT
""""""""""""""""""""""""""""""""""""""""
This is the simplest case. Both the DLL and the program have ``GDB``
-compatible debugging information. It is then possible to break anywhere in
-the process. Let's suppose here that the main procedure is named
-``ada_main`` and that in the DLL there is an entry point named
+compatible debugging information. You can then break anywhere in
+the process. Let's suppose the main procedure is named
+``ada_main`` and in the DLL there's an entry point named
``ada_dll``.
The DLL (:ref:`Introduction_to_Dynamic_Link_Libraries_DLLs`) and
-program must have been built with the debugging information (see GNAT -g
-switch). Here are the step-by-step instructions for debugging it:
+program must have been built with the debugging information (see the GNAT
+:switch:`-g` switch). Here are the step-by-step instructions for debugging it:
* Launch ``GDB`` on the main program.
@@ -2055,10 +2057,10 @@ switch). Here are the step-by-step instructions for debugging it:
(gdb) start
- This step is required to be able to set a breakpoint inside the DLL. As long
- as the program is not run, the DLL is not loaded. This has the
- consequence that the DLL debugging information is also not loaded, so it is not
- possible to set a breakpoint in the DLL.
+ This step is required to be able to set a breakpoint inside
+ the DLL. Until the program is run, the DLL is not loaded. This has
+ the consequence that the DLL debugging information is also not
+ loaded, so it is not possible to set a breakpoint in the DLL.
* Set a breakpoint inside the DLL
@@ -2067,8 +2069,8 @@ switch). Here are the step-by-step instructions for debugging it:
(gdb) break ada_dll
(gdb) cont
-At this stage a breakpoint is set inside the DLL. From there on
-you can use the standard approach to debug the whole program
+At this stage, a breakpoint is set inside the DLL. From there on
+you can use standard ``GDB`` commands to debug the whole program
(:ref:`Running_and_Debugging_Ada_Programs`).
@@ -2077,26 +2079,26 @@ you can use the standard approach to debug the whole program
Program Built with Foreign Tools and DLL Built with GCC/GNAT
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-In this case things are slightly more complex because it is not possible to
+In this case, things are slightly more complex because you can't
start the main program and then break at the beginning to load the DLL and the
-associated DLL debugging information. It is not possible to break at the
-beginning of the program because there is no ``GDB`` debugging information,
-and therefore there is no direct way of getting initial control. This
-section addresses this issue by describing some methods that can be used
+associated DLL debugging information. It's not possible to break at the
+beginning of the program because there's no ``GDB`` debugging information,
+and therefore there's no direct way of getting initial control. This
+section addresses this issue by describing some methods that you can use
to break somewhere in the DLL to debug it.
-First suppose that the main procedure is named ``main`` (this is for
-example some C code built with Microsoft Visual C) and that there is a
-DLL named ``test.dll`` containing an Ada entry point named
+First, suppose that the main procedure is named ``main`` (this is the
+case, for example, for some C code built with Microsoft Visual C) and that
+there's a DLL named ``test.dll`` containing an Ada entry point named
``ada_dll``.
The DLL (see :ref:`Introduction_to_Dynamic_Link_Libraries_DLLs`) must have
-been built with debugging information (see the GNAT :switch:`-g` option).
+been built with debugging information (see the GNAT :switch:`-g` switch).
.. rubric:: Debugging the DLL Directly
-* Find out the executable starting address
+* Determine the executable's starting address
::
@@ -2117,14 +2119,14 @@ been built with debugging information (see the GNAT :switch:`-g` option).
$ gdb main.exe
-* Set a breakpoint at the starting address, and launch the program.
+* Set a breakpoint at the starting address and launch the program.
::
$ (gdb) break *0x00401010
$ (gdb) run
- The program will stop at the given address.
+ The program will stop at the specified address.
* Set a breakpoint on a DLL subroutine.
@@ -2146,22 +2148,23 @@ been built with debugging information (see the GNAT :switch:`-g` option).
(gdb) cont
- This will run the program until it reaches the breakpoint that has been
- set. From that point you can use the standard way to debug a program
- as described in (:ref:`Running_and_Debugging_Ada_Programs`).
+ This runs the program until it reaches the breakpoint that you've
+ set. From that point, you can use standard ``GDB`` commands to debug
+ a program as described in
+ (:ref:`Running_and_Debugging_Ada_Programs`).
-It is also possible to debug the DLL by attaching to a running process.
+You can also debug the DLL by attaching ``GDB`` to a running process.
.. rubric:: Attaching to a Running Process
.. index:: DLL debugging, attach to process
-With ``GDB`` it is always possible to debug a running process by
-attaching to it. It is possible to debug a DLL this way. The limitation
-of this approach is that the DLL must run long enough to perform the
-attach operation. It may be useful for instance to insert a time wasting
-loop in the code of the DLL to meet this criterion.
+With ``GDB``, you can always debug a running process by attaching to
+it. It's possible to debug a DLL this way. The limitation of this
+approach is that the DLL must run long enough to perform the attach
+operation. To ensure this, you may want, for example, to insert a
+time-wasting loop in the code of the DLL to allow this to happen.
* Launch the main program :file:`main.exe`.
@@ -2202,9 +2205,9 @@ loop in the code of the DLL to meet this criterion.
(gdb) cont
-This last step will resume the process execution, and stop at
-the breakpoint we have set. From there you can use the standard
-approach to debug a program as described in
+This last step will resume the process execution and stop at
+the breakpoint we have set. From there you can use standard
+``GDB`` commands to debug a program, as described in
:ref:`Running_and_Debugging_Ada_Programs`.
@@ -2213,21 +2216,21 @@ approach to debug a program as described in
Setting Stack Size from ``gnatlink``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-It is possible to specify the program stack size at link time. On modern
-versions of Windows, starting with XP, this is mostly useful to set the size of
-the main stack (environment task). The other task stacks are set with pragma
-Storage_Size or with the *gnatbind -d* command.
+You can specify the program stack size at link time. On most versions
+of Windows, starting with XP, this is mostly useful to set the size of
+the main stack (environment task). The other task stacks are set with
+pragma Storage_Size or with the *gnatbind -d* command.
-Since older versions of Windows (2000, NT4, etc.) do not allow setting the
+Since very old versions of Windows (2000, NT4, etc.) don't allow setting the
reserve size of individual tasks, the link-time stack size applies to all
tasks, and pragma Storage_Size has no effect.
In particular, Stack Overflow checks are made against this
link-time specified size.
-This setting can be done with ``gnatlink`` using either of the following:
+You can set this with ``gnatlink`` using either of the following:
-* :switch:`-Xlinker` linker option
+* :switch:`-Xlinker` linker switch
::
@@ -2237,15 +2240,15 @@ This setting can be done with ``gnatlink`` using either of the following:
This sets the stack reserve size to 0x10000 bytes and the stack commit
size to 0x1000 bytes.
-* :switch:`-Wl` linker option
+* :switch:`-Wl` linker switch
::
$ gnatlink hello -Wl,--stack=0x1000000
This sets the stack reserve size to 0x1000000 bytes. Note that with
- :switch:`-Wl` option it is not possible to set the stack commit size
- because the comma is a separator for this option.
+ :switch:`-Wl` switch, you can't also set the stack commit size
+ because the comma is a separator for this switch.
.. _Setting_Heap_Size_from_gnatlink:
@@ -2256,7 +2259,7 @@ Setting Heap Size from ``gnatlink``
Under Windows systems, it is possible to specify the program heap size from
``gnatlink`` using either of the following:
-* :switch:`-Xlinker` linker option
+* :switch:`-Xlinker` linker switch
::
@@ -2265,7 +2268,7 @@ Under Windows systems, it is possible to specify the program heap size from
This sets the heap reserve size to 0x10000 bytes and the heap commit
size to 0x1000 bytes.
-* :switch:`-Wl` linker option
+* :switch:`-Wl` linker switch
::
@@ -2273,8 +2276,8 @@ Under Windows systems, it is possible to specify the program heap size from
This sets the heap reserve size to 0x1000000 bytes. Note that with
- :switch:`-Wl` option it is not possible to set the heap commit size
- because the comma is a separator for this option.
+ :switch:`-Wl` switch, you can't also set the heap commit size
+ because the comma is a separator for this switch.
.. _Win32_Specific_Addons:
@@ -2289,10 +2292,10 @@ This section describes the Windows specific add-ons.
Win32Ada
^^^^^^^^
-Win32Ada is a binding for the Microsoft Win32 API. This binding can be
-easily installed from the provided installer. To use the Win32Ada
-binding you need to use a project file, and adding a single with_clause
-will give you full access to the Win32Ada binding sources and ensure
+``Win32Ada`` is a binding for the Microsoft Win32 API, which you can
+easily install using the provided installer. To use it,
+you need to use a project file and add a single with_clause
+to give you full access to the ``Win32Ada`` binding sources and ensure
that the proper libraries are passed to the linker.
.. code-block:: gpr
@@ -2302,8 +2305,8 @@ that the proper libraries are passed to the linker.
for Sources use ...;
end P;
-To build the application you just need to call gprbuild for the
-application's project, here p.gpr:
+To build the application, you just need to call ``gprbuild`` for the
+application's project, here :file:`p.gpr`:
.. code-block:: sh
@@ -2314,12 +2317,12 @@ application's project, here p.gpr:
wPOSIX
^^^^^^
-wPOSIX is a minimal POSIX binding whose goal is to help with building
+``wPOSIX`` is a minimal POSIX binding whose goal is to help with building
cross-platforms applications. This binding is not complete though, as
the Win32 API does not provide the necessary support for all POSIX APIs.
-To use the wPOSIX binding you need to use a project file, and adding
-a single with_clause will give you full access to the wPOSIX binding
+To use the ``wPOSIX`` binding, you need to use a project file and add
+a single *with* clause to give you full access to the ``wPOSIX`` binding
sources and ensure that the proper libraries are passed to the linker.
.. code-block:: gpr
@@ -2329,8 +2332,8 @@ sources and ensure that the proper libraries are passed to the linker.
for Sources use ...;
end P;
-To build the application you just need to call gprbuild for the
-application's project, here p.gpr:
+To build the application, you just need to call ``gprbuild`` for the
+application's project, here :file:`p.gpr`:
.. code-block:: sh
@@ -2350,10 +2353,11 @@ platform.
Codesigning the Debugger
------------------------
-The Darwin Kernel requires the debugger to have special permissions
-before it is allowed to control other processes. These permissions
-are granted by codesigning the GDB executable. Without these
-permissions, the debugger will report error messages such as::
+The Darwin Kernel, used by Apple's OS X, requires the debugger to have
+special permissions before it's allowed to control other
+processes. These permissions are granted by codesigning the GDB
+executable. Without these permissions, the debugger will report error
+messages such as::
Starting program: /x/y/foo
Unable to find Mach task port for process-id 28885: (os/kern) failure (0x5).
@@ -2392,14 +2396,14 @@ how to create one:
(this is unfortunately required)
-Once a certificate has been created, the debugger can be codesigned
-as follow. In a Terminal, run the following command:
+Once you've created a certificate as above, you can codesign the debugger
+by running the following command in a Terminal:
::
$ codesign -f -s "gdb-cert" <gnat_install_prefix>/bin/gdb
-where "gdb-cert" should be replaced by the actual certificate
-name chosen above, and <gnat_install_prefix> should be replaced by
-the location where you installed GNAT. Also, be sure that users are
-in the Unix group ``_developer``.
+with ``gdb-cert`` replaced by the actual certificate name chosen
+above, and ``gnat_install_prefix`` replaced by the location where you
+installed GNAT. Also, be sure that users of ``GDB`` are in the Unix
+group ``_developer``.
@@ -53,7 +53,7 @@ Source Representation
Ada source programs are represented in standard text files, using
Latin-1 coding. Latin-1 is an 8-bit code that includes the familiar
-7-bit ASCII set, plus additional characters used for
+7-bit ASCII set plus additional characters used for
representing foreign languages (see :ref:`Foreign_Language_Representation`
for support of non-USA character sets). The format effector characters
are represented using their standard ASCII encodings, as follows:
@@ -68,11 +68,11 @@ are represented using their standard ASCII encodings, as follows:
:kbd:`FF` Form feed ``16#0C#``
=========== ======================= ===========
-Source files are in standard text file format. In addition, GNAT will
-recognize a wide variety of stream formats, in which the end of
+Source files are in standard text file format. In addition, GNAT
+recognizes a wide variety of stream formats, in which the end of
physical lines is marked by any of the following sequences:
``LF``, ``CR``, ``CR-LF``, or ``LF-CR``. This is useful
-in accommodating files that are imported from other operating systems.
+in accommodating files imported from other operating systems.
.. index:: pair: End of source file; Source file, end
@@ -81,7 +81,7 @@ in accommodating files that are imported from other operating systems.
The end of a source file is normally represented by the physical end of
file. However, the control character ``16#1A#`` (:kbd:`SUB`) is also
recognized as signalling the end of the source file. Again, this is
-provided for compatibility with other operating systems where this
+provided for compatibility with other, legacy, operating systems where this
code is used to represent the end of file.
.. index:: spec (definition), compilation (definition)
@@ -91,7 +91,7 @@ associated with the unit. For example, this means you must place a
package declaration (a package *spec*) and the corresponding body in
separate files. An Ada *compilation* (which is a sequence of
compilation units) is represented using a sequence of files. Similarly,
-you will place each subunit or child unit in a separate file.
+you place each subunit or child unit in a separate file.
.. _Foreign_Language_Representation:
@@ -111,7 +111,7 @@ Latin-1
The basic character set is Latin-1. This character set is defined by ISO
standard 8859, part 1. The lower half (character codes ``16#00#``
-... ``16#7F#)`` is identical to standard ASCII coding, but the upper
+... ``16#7F#)`` is identical to standard ASCII coding but the upper
half is used to represent additional characters. These include extended letters
used by European languages, such as French accents, the vowels with umlauts
used in German, and the extra letter A-ring used in Swedish.
@@ -173,7 +173,7 @@ GNAT also supports several other 8-bit coding schemes:
.. index:: code page 437 (IBM PC)
*IBM PC (code page 437)*
- This code page is the normal default for PCs in the U.S. It corresponds
+ This code page is the normal default for PCs in the US. It corresponds
to the original IBM PC character set. This set has some, but not all, of
the extended Latin-1 letters, but these letters do not have the same
encoding as Latin-1. In this mode, these letters are allowed in
@@ -189,7 +189,7 @@ GNAT also supports several other 8-bit coding schemes:
*Full Upper 8-bit*
- Any character in the range 80-FF allowed in identifiers, and all are
+ Any character in the range 80-FF is allowed in identifiers and all are
considered distinct. In other words, there are no uppercase and lowercase
equivalences in this range. This is useful in conjunction with
certain encoding schemes used for some foreign character sets (e.g.,
@@ -244,18 +244,17 @@ possible encoding schemes:
``16#cd#``, with the restrictions described for upper-half encoding as
described above. The internal character code is the corresponding JIS
character according to the standard algorithm for Shift-JIS
- conversion. Only characters defined in the JIS code set table can be
- used with this encoding method.
+ conversion. You can only use characters defined in the JIS code set table
+ with this encoding method.
.. index:: EUC Coding
*EUC Coding*
A wide character is represented by a two-character sequence
- ``16#ab#`` and
- ``16#cd#``, with both characters being in the upper half. The internal
- character code is the corresponding JIS character according to the EUC
- encoding algorithm. Only characters defined in the JIS code set table
- can be used with this encoding method.
+ ``16#ab#`` and ``16#cd#``, with both characters being in the upper
+ half. The internal character code is the corresponding JIS character
+ according to the EUC encoding algorithm. You can only use characters
+ defined in the JIS code set table with this encoding method.
*UTF-8 Coding*
@@ -273,8 +272,8 @@ possible encoding schemes:
are represented as ASCII bytes and all upper half characters and
other wide characters are represented as sequences of upper-half
(The full UTF-8 scheme allows for encoding 31-bit characters as
- 6-byte sequences, and in the following section on wide wide
- characters, the use of these sequences is documented).
+ 6-byte sequences the use of these sequences is documented in the
+ following section on wide wide characters.)
*Brackets Coding*
@@ -283,14 +282,14 @@ possible encoding schemes:
[ " a b c d " ]
- where ``a``, ``b``, ``c``, ``d`` are the four hexadecimal
- characters (using uppercase letters) of the wide character code. For
- example, ['A345'] is used to represent the wide character with code
- ``16#A345#``. It is also possible (though not required) to use the
- Brackets coding for upper half characters. For example, the code
- ``16#A3#`` can be represented as ``['A3']``.
+ where ``a``, ``b``, ``c``, ``d`` are the four hexadecimal characters
+ (using uppercase letters) of the wide character code. For example,
+ ['A345'] is used to represent the wide character with code
+ ``16#A345#``. You can also (though you are not required to) use the
+ Brackets coding for upper half characters. For example, you can
+ represent the code ``16#A3#`` as ``['A3']``.
- This scheme is compatible with use of the full Wide_Character set,
+ This scheme is compatible with use of the full ``Wide_Character`` set,
and is also the method used for wide character encoding in some standard
ACATS (Ada Conformity Assessment Test Suite) test suite distributions.
@@ -339,7 +338,7 @@ possible encoding schemes:
example, ["1F4567"] is used to represent the wide wide character with code
``16#001F_4567#``.
- This scheme is compatible with use of the full Wide_Wide_Character set,
+ This scheme is compatible with use of the full ``Wide_Wide_Character`` set,
and is also the method used for wide wide character encoding in some standard
ACATS (Ada Conformity Assessment Test Suite) test suite distributions.
@@ -349,9 +348,10 @@ possible encoding schemes:
File Naming Topics and Utilities
================================
-GNAT has a default file naming scheme and also provides the user with
-a high degree of control over how the names and extensions of the
-source files correspond to the Ada compilation units that they contain.
+GNAT has a default file naming scheme, but and also provides you
+with a high degree of control over how the names and extensions of your
+source files correspond to the Ada compilation units that they
+contain.
.. _File_Naming_Rules:
@@ -359,18 +359,18 @@ source files correspond to the Ada compilation units that they contain.
File Naming Rules
-----------------
-The default file name is determined by the name of the unit that the
+GNAT determines the default file name by the name of the unit that the
file contains. The name is formed by taking the full expanded name of
-the unit and replacing the separating dots with hyphens and using
+the unit, replacing the separating dots with hyphens, and using
lowercase for all letters.
-An exception arises if the file name generated by the above rules starts
+An exception occurs if the file name generated by the above rules starts
with one of the characters
-``a``, ``g``, ``i``, or ``s``, and the second character is a
-minus. In this case, the character tilde is used in place
-of the minus. The reason for this special rule is to avoid clashes with
-the standard names for child units of the packages System, Ada,
-Interfaces, and GNAT, which use the prefixes
+``a``, ``g``, ``i``, or ``s`` and the second character is a
+hyphen. In this case, the character tilde is used in place
+of the hypen. This special rule avoids clashes with
+the standard names for child units of the packages ``System``, ``Ada``,
+``Interfaces``, and ``GNAT``, which use the prefixes
``s-``, ``a-``, ``i-``, and ``g-``,
respectively.
@@ -395,23 +395,23 @@ Following these rules can result in excessively long
file names if corresponding
unit names are long (for example, if child units or subunits are
heavily nested). An option is available to shorten such long file names
-(called file name 'krunching'). This may be particularly useful when
+(called file name 'krunching'). You may find this particularly useful when
programs being developed with GNAT are to be used on operating systems
with limited file name lengths. :ref:`Using_gnatkr`.
Of course, no file shortening algorithm can guarantee uniqueness over
all possible unit names; if file name krunching is used, it is your
-responsibility to ensure no name clashes occur. Alternatively you
+responsibility to ensure no name clashes occur. Alternatively, you
can specify the exact file names that you want used, as described
in the next section. Finally, if your Ada programs are migrating from a
-compiler with a different naming convention, you can use the gnatchop
+compiler with a different naming convention, you can use the ``gnatchop``
utility to produce source files that follow the GNAT naming conventions.
(For details see :ref:`Renaming_Files_with_gnatchop`.)
Note: in the case of Windows or Mac OS operating systems, case is not
-significant. So for example on Windows if the canonical name is
+significant. So, for example, on Windows if the canonical name is
:file:`main-sub.adb`, you can use the file name :file:`Main-Sub.adb` instead.
-However, case is significant for other operating systems, so for example,
+However, case is significant for other operating systems, so, for example,
if you want to use other than canonically cased file names on a Unix system,
you need to follow the procedures described in the next section.
@@ -422,18 +422,18 @@ Using Other File Names
.. index:: File names
-In the previous section, we have described the default rules used by
+The previous section described the default rules used by
GNAT to determine the file name in which a given unit resides. It is
-often convenient to follow these default rules, and if you follow them,
+usually convenient to follow these default rules, and if you follow them,
the compiler knows without being explicitly told where to find all
the files it needs.
.. index:: Source_File_Name pragma
However, in some cases, particularly when a program is imported from
-another Ada compiler environment, it may be more convenient for the
-programmer to specify which file names contain which units. GNAT allows
-arbitrary file names to be used by means of the Source_File_Name pragma.
+another Ada compiler environment, it may be more convenient for you
+to specify which file names contain which units. GNAT allows
+arbitrary file names to be used by means of the ``Source_File_Name`` pragma.
The form of this pragma is as shown in the following examples:
.. code-block:: ada
@@ -450,7 +450,7 @@ indicates whether the file name is for a spec or a body;
the file name itself is given by a string literal.
The source file name pragma is a configuration pragma, which means that
-normally it will be placed in the :file:`gnat.adc`
+normally you will place it in the :file:`gnat.adc`
file used to hold configuration
pragmas that apply to a complete compilation environment.
For more details on how the :file:`gnat.adc` file is created and used
@@ -458,12 +458,12 @@ see :ref:`Handling_of_Configuration_Pragmas`.
.. index:: gnat.adc
-GNAT allows completely arbitrary file names to be specified using the
+GNAT allows you to specify completely arbitrary file names using the
source file name pragma. However, if the file name specified has an
-extension other than :file:`.ads` or :file:`.adb` it is necessary to use
-a special syntax when compiling the file. The name in this case must be
-preceded by the special sequence ``-x`` followed by a space and the name
-of the language, here ``ada``, as in:
+extension other than :file:`.ads` or :file:`.adb` you must use a
+special syntax when compiling the file. The name on the command line
+in this case must be preceded by the special sequence ``-x`` followed
+by a space and the name of the language, here ``ada``, as in:
.. code-block:: sh
@@ -471,8 +471,8 @@ of the language, here ``ada``, as in:
``gnatmake`` handles non-standard file names in the usual manner (the
non-standard file name for the main program is simply used as the
-argument to gnatmake). Note that if the extension is also non-standard,
-then it must be included in the ``gnatmake`` command, it may not
+argument to ``gnatmake``). Note that if the extension is also non-standard,
+you must include it in the ``gnatmake`` command; it may not
be omitted.
.. _Alternative_File_Naming_Schemes:
@@ -486,8 +486,8 @@ Alternative File Naming Schemes
The previous section described the use of the ``Source_File_Name``
pragma to allow arbitrary names to be assigned to individual source files.
-However, this approach requires one pragma for each file, and especially in
-large systems can result in very long :file:`gnat.adc` files, and also create
+However, this approach requires one pragma for each file and, especially in
+large systems, can result in very long :file:`gnat.adc` files, which can create
a maintenance problem.
.. index:: Source_File_Name pragma
@@ -523,48 +523,46 @@ systematically for this asterisk. The optional parameter
``Casing`` indicates
whether the unit name is to be all upper-case letters, all lower-case letters,
or mixed-case. If no
-``Casing`` parameter is used, then the default is all
+``Casing`` parameter is used, the default is all
lower-case.
-The optional ``Dot_Replacement`` string is used to replace any periods
-that occur in subunit or child unit names. If no ``Dot_Replacement``
-argument is used then separating dots appear unchanged in the resulting
-file name.
-Although the above syntax indicates that the
-``Casing`` argument must appear
-before the ``Dot_Replacement`` argument, but it
-is also permissible to write these arguments in the opposite order.
-
-As indicated, it is possible to specify different naming schemes for
-bodies, specs, and subunits. Quite often the rule for subunits is the
-same as the rule for bodies, in which case, there is no need to give
-a separate ``Subunit_File_Name`` rule, and in this case the
+You use the optional ``Dot_Replacement`` string to replace any periods
+that occur in subunit or child unit names. If you don't specify a
+``Dot_Replacement`` argument, separating dots appear unchanged in the
+resulting file name. The above syntax indicates that the ``Casing``
+argument must appear before the ``Dot_Replacement`` argument, but you
+can write these arguments in any order.
+
+As indicated, you can specify different naming schemes for
+bodies, specs, and subunits. Quite often, the rule for subunits is the
+same as the rule for bodies, in which case, you need not provide
+a separate ``Subunit_File_Name`` rule; in this case the
``Body_File_name`` rule is used for subunits as well.
-The separate rule for subunits can also be used to implement the rather
+You can also use the separate rule for subunits to implement the rather
unusual case of a compilation environment (e.g., a single directory) which
contains a subunit and a child unit with the same unit name. Although
both units cannot appear in the same partition, the Ada Reference Manual
allows (but does not require) the possibility of the two units coexisting
in the same environment.
-The file name translation works in the following steps:
+File name translation consists of the following steps:
* If there is a specific ``Source_File_Name`` pragma for the given unit,
- then this is always used, and any general pattern rules are ignored.
+ this is always used and any general pattern rules are ignored.
* If there is a pattern type ``Source_File_Name`` pragma that applies to
- the unit, then the resulting file name will be used if the file exists. If
- more than one pattern matches, the latest one will be tried first, and the
- first attempt resulting in a reference to a file that exists will be used.
+ the unit, the resulting file name is used if the file exists. If
+ more than one pattern matches, the latest one is tried first and the
+ first attempt that results in a reference to a file that exists is used.
* If no pattern type ``Source_File_Name`` pragma that applies to the unit
- for which the corresponding file exists, then the standard GNAT default
+ for which the corresponding file exists, the standard GNAT default
naming rules are used.
As an example of the use of this mechanism, consider a commonly used scheme
in which file names are all lower case, with separating periods copied
-unchanged to the resulting file name, and specs end with :file:`.1.ada`, and
+unchanged to the resulting file name, specs end with :file:`.1.ada`, and
bodies end with :file:`.2.ada`. GNAT will follow this scheme if the following
two pragmas appear:
@@ -575,8 +573,8 @@ two pragmas appear:
pragma Source_File_Name
(Body_File_Name => ".2.ada");
-The default GNAT scheme is actually implemented by providing the following
-default pragmas internally:
+The default GNAT scheme is equivalent to providing the following
+default pragmas:
.. code-block:: ada
@@ -586,11 +584,11 @@ default pragmas internally:
(Body_File_Name => ".adb", Dot_Replacement => "-");
Our final example implements a scheme typically used with one of the
-Ada 83 compilers, where the separator character for subunits was '__'
+legacy Ada 83 compilers, where the separator character for subunits was '__'
(two underscores), specs were identified by adding :file:`_.ADA`, bodies
by adding :file:`.ADA`, and subunits by
adding :file:`.SEP`. All file names were
-upper case. Child units were not present of course since this was an
+upper case. Child units were not present, of course, since this was an
Ada 83 compiler, but it seems reasonable to extend this scheme to use
the same double underscore separator for child units.
@@ -624,24 +622,23 @@ Handling Arbitrary File Naming Conventions with ``gnatname``
Arbitrary File Naming Conventions
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-The GNAT compiler must be able to know the source file name of a compilation
-unit. When using the standard GNAT default file naming conventions
-(``.ads`` for specs, ``.adb`` for bodies), the GNAT compiler
+The GNAT compiler must know the source file name of a compilation unit
+in order to compile it. When using the standard GNAT default file
+naming conventions (``.ads`` for specs, ``.adb`` for bodies), it
does not need additional information.
-When the source file names do not follow the standard GNAT default file naming
-conventions, the GNAT compiler must be given additional information through
-a configuration pragmas file (:ref:`Configuration_Pragmas`)
-or a project file.
-When the non-standard file naming conventions are well-defined,
-a small number of pragmas ``Source_File_Name`` specifying a naming pattern
+When the source file names do not follow the standard GNAT default
+file naming conventions, you must give the GNAT compiler additional
+information through a configuration pragmas file
+(:ref:`Configuration_Pragmas`) or a project file. When the
+non-standard file naming conventions are well-defined, a small number
+of pragmas ``Source_File_Name`` specifying a naming pattern
(:ref:`Alternative_File_Naming_Schemes`) may be sufficient. However,
-if the file naming conventions are irregular or arbitrary, a number
-of pragma ``Source_File_Name`` for individual compilation units
-must be defined.
-To help maintain the correspondence between compilation unit names and
-source file names within the compiler,
-GNAT provides a tool ``gnatname`` to generate the required pragmas for a
+if the file naming conventions are irregular or arbitrary, you must
+define a number of pragma ``Source_File_Name`` for individual
+compilation units. To help maintain the correspondence between
+compilation unit names and source file names within the compiler, GNAT
+provides a tool ``gnatname`` to generate the required pragmas for a
set of files.
.. _Running_gnatname:
@@ -657,27 +654,28 @@ The usual form of the ``gnatname`` command is:
[--and [ switches ] naming_pattern [ naming_patterns ]]
-All of the arguments are optional. If invoked without any argument,
+All of the arguments are optional. If invoked without any arguments,
``gnatname`` will display its usage.
-When used with at least one naming pattern, ``gnatname`` will attempt to
+When used with at least one naming pattern, ``gnatname`` attempts to
find all the compilation units in files that follow at least one of the
naming patterns. To find these compilation units,
-``gnatname`` will use the GNAT compiler in syntax-check-only mode on all
+``gnatname`` uses the GNAT compiler in syntax-check-only mode on all
regular files.
-One or several Naming Patterns may be given as arguments to ``gnatname``.
+One or several *Naming Patterns* may be given as arguments to ``gnatname``.
Each Naming Pattern is enclosed between double quotes (or single
quotes on Windows).
A Naming Pattern is a regular expression similar to the wildcard patterns
used in file names by the Unix shells or the DOS prompt.
-``gnatname`` may be called with several sections of directories/patterns.
-Sections are separated by the switch :switch:`--and`. In each section, there must be
-at least one pattern. If no directory is specified in a section, the current
-directory (or the project directory if :switch:`-P` is used) is implied.
-The options other that the directory switches and the patterns apply globally
-even if they are in different sections.
+You may call ``gnatname`` with several sections of
+directories/patterns. Sections are separated by the switch
+:switch:`--and`. In each section, you must include at least one
+pattern. If you don't specify a directory a section, the current
+directory (or the project directory if :switch:`-P` is used) is
+used. The options other that the directory switches and the
+patterns apply globally even if they are in different sections.
Examples of Naming Patterns are::
@@ -706,16 +704,16 @@ You may specify any of the following switches to ``gnatname``:
.. index:: --version (gnatname)
:switch:`--version`
- Display Copyright and version, then exit disregarding all other options.
+ Display Copyright and version, then exit disregarding, all other options.
.. index:: --help (gnatname)
:switch:`--help`
- If :switch:`--version` was not used, display usage, then exit disregarding
+ If :switch:`--version` was not used, display usage, then exit, disregarding
all other options.
:switch:`--subdirs={dir}`
- Real object, library or exec directories are subdirectories <dir> of the
+ Actual object, library or exec directories are subdirectories <dir> of the
specified ones.
:switch:`--no-backup`
@@ -729,41 +727,41 @@ You may specify any of the following switches to ``gnatname``:
:switch:`-c{filename}`
Create a configuration pragmas file :file:`filename` (instead of the default
:file:`gnat.adc`).
- There may be zero, one or more space between :switch:`-c` and
+ There may be zero, one, or more space between :switch:`-c` and
:file:`filename`.
:file:`filename` may include directory information. :file:`filename` must be
- writable. There may be only one switch :switch:`-c`.
+ writable. You can specify only one switch :switch:`-c`.
When a switch :switch:`-c` is
- specified, no switch :switch:`-P` may be specified (see below).
+ specified, you may not specify switch :switch:`-P` (see below).
.. index:: -d (gnatname)
:switch:`-d{dir}`
- Look for source files in directory :file:`dir`. There may be zero, one or more
+ Look for source files in directory :file:`dir`. You may put zero, one or more
spaces between :switch:`-d` and :file:`dir`.
- :file:`dir` may end with ``/**``, that is it may be of the form
+ :file:`dir` may end with ``/**``, i.e., you may write it the form
``root_dir/**``. In this case, the directory ``root_dir`` and all of its
subdirectories, recursively, have to be searched for sources.
- When a switch :switch:`-d`
- is specified, the current working directory will not be searched for source
- files, unless it is explicitly specified with a :switch:`-d`
+ When you specify a :switch:`-d` switch,
+ the current working directory will is not searched for source
+ files unless you explicitly specify it with a :switch:`-d`
or :switch:`-D` switch.
- Several switches :switch:`-d` may be specified.
+ You may specify several switches :switch:`-d`.
If :file:`dir` is a relative path, it is relative to the directory of
the configuration pragmas file specified with switch
:switch:`-c`,
or to the directory of the project file specified with switch
:switch:`-P` or,
- if neither switch :switch:`-c`
- nor switch :switch:`-P` are specified, it is relative to the
+ if you don't specify either switch :switch:`-c`
+ or switch :switch:`-P`, it's relative to the
current working directory. The directory
- specified with switch :switch:`-d` must exist and be readable.
+ you specified with switch :switch:`-d` must exist and be readable.
.. index:: -D (gnatname)
:switch:`-D{filename}`
Look for source files in all directories listed in text file :file:`filename`.
- There may be zero, one or more spaces between :switch:`-D`
+ You may place zero, one or more spaces between :switch:`-D`
and :file:`filename`.
:file:`filename` must be an existing, readable text file.
Each nonempty line in :file:`filename` must be a directory.
@@ -777,18 +775,18 @@ You may specify any of the following switches to ``gnatname``:
.. index:: -f (gnatname)
:switch:`-f{pattern}`
- Foreign patterns. Using this switch, it is possible to add sources of languages
- other than Ada to the list of sources of a project file.
- It is only useful if a -P switch is used.
+ Foreign patterns. Using this switch, you can add sources of languages
+ other than Ada to the list of sources of a project file, but
+ it's only useful if you also specify a :switch:`-P` switch.
For example,
.. code-block:: sh
gnatname -Pprj -f"*.c" "*.ada"
- will look for Ada units in all files with the :file:`.ada` extension,
- and will add to the list of file for project :file:`prj.gpr` the C files
- with extension :file:`.c`.
+ looks for Ada units in all files with the :file:`.ada` extension,
+ and adds the C files with extension :file:`.c` to the list of file
+ for project :file:`prj.gpr` .
.. index:: -h (gnatname)
@@ -798,44 +796,46 @@ You may specify any of the following switches to ``gnatname``:
.. index:: -P (gnatname)
:switch:`-P{proj}`
- Create or update project file :file:`proj`. There may be zero, one or more space
- between :switch:`-P` and :file:`proj`. :file:`proj` may include directory
- information. :file:`proj` must be writable.
- There may be only one switch :switch:`-P`.
- When a switch :switch:`-P` is specified,
- no switch :switch:`-c` may be specified.
- On all platforms, except on VMS, when ``gnatname`` is invoked for an
- existing project file <proj>.gpr, a backup copy of the project file is created
- in the project directory with file name <proj>.gpr.saved_x. 'x' is the first
- non negative number that makes this backup copy a new file.
+
+ Create or update project file :file:`proj`. You may place zero, one
+ or more space between :switch:`-P` and :file:`proj`. :file:`proj`
+ may include directory information. :file:`proj` must be writable.
+ There may be only one switch :switch:`-P`. When you specify switch
+ :switch:`-P`, you may not also include switch :switch:`-c`. On all
+ platforms except VMS when ``gnatname`` is invoked for an existing
+ project file :file:`<proj>.gpr``, ``gnatname`` creates a backup copy
+ of the project file in the project directory with file name
+ :file:`<proj>.gpr.saved_x` where ``x`` is the first non negative
+ number that creates a unique filename.
.. index:: -v (gnatname)
:switch:`-v`
- Verbose mode. Output detailed explanation of behavior to :file:`stdout`.
- This includes name of the file written, the name of the directories to search
+ Verbose mode. Output detailed explanation of what it's doing to :file:`stdout`.
+ This includes name of the file written, the name of the directories searched,
and, for each file in those directories whose name matches at least one of
the Naming Patterns, an indication of whether the file contains a unit,
- and if so the name of the unit.
+ and, if so, the name of the unit.
.. index:: -v -v (gnatname)
:switch:`-v -v`
- Very Verbose mode. In addition to the output produced in verbose mode,
+ Very verbose mode. In addition to the output produced in verbose mode
+ (a single :switch:`-v` switch),
for each file in the searched directories whose name matches none of
- the Naming Patterns, an indication is given that there is no match.
+ the Naming Patterns, ``gnatname`` indicates that there is no match.
.. index:: -x (gnatname)
:switch:`-x{pattern}`
- Excluded patterns. Using this switch, it is possible to exclude some files
- that would match the name patterns. For example,
+ Excluded patterns. Using this switch, you can exclude some files
+ that otherwise would match the name patterns. For example,
.. code-block:: sh
gnatname -x "*_nt.ada" "*.ada"
- will look for Ada units in all files with the :file:`.ada` extension,
+ looks for Ada units in all files with the :file:`.ada` extension,
except those whose names end with :file:`_nt.ada`.
@@ -860,10 +860,9 @@ Note the optional spaces after :switch:`-c` and :switch:`-d`.
$ gnatname -P/home/me/proj -x "*_nt_body.ada"
-dsources -dsources/plus -Dcommon_dirs.txt "body_*" "spec_*"
-Note that several switches :switch:`-d` may be used,
-even in conjunction with one or several switches
-:switch:`-D`. Several Naming Patterns and one excluded pattern
-are used in this example.
+Note that you may use several :switch:`-d` switches, even in
+conjunction with one or several :switch:`-D` switches. This example
+illustrates multiple Naming Patterns and one excluded pattern.
.. _File_Name_Krunching_with_gnatkr:
@@ -873,10 +872,10 @@ File Name Krunching with ``gnatkr``
.. index:: ! gnatkr
-This section discusses the method used by the compiler to shorten
+Here we discuss the method used by the compiler to shorten
the default file names chosen for Ada units so that they do not
-exceed the maximum length permitted. It also describes the
-``gnatkr`` utility that can be used to determine the result of
+exceed the maximum length permitted. We also describe the
+``gnatkr`` utility, which you can use to determine the result of
applying this shortening.
.. _About_gnatkr:
@@ -884,9 +883,8 @@ applying this shortening.
About ``gnatkr``
^^^^^^^^^^^^^^^^
-The default file naming rule in GNAT
-is that the file name must be derived from
-the unit name. The exact default rule is as follows:
+GNAT requires that the file name must be derived from the unit
+name. The default rule is as follows:
* Take the unit name and replace all dots by hyphens.
@@ -895,9 +893,9 @@ the unit name. The exact default rule is as follows:
:samp:`a`, :samp:`g`, :samp:`s`, or :samp:`i`,
then replace the dot by the character
:samp:`~` (tilde)
- instead of a minus.
+ instead of a hyphen.
- The reason for this exception is to avoid clashes
+ This exception avoids clashes
with the standard names for children of System, Ada, Interfaces,
and GNAT, which use the prefixes
:samp:`s-`, :samp:`a-`, :samp:`i-`, and :samp:`g-`,
@@ -905,44 +903,45 @@ the unit name. The exact default rule is as follows:
The :switch:`-gnatk{nn}`
switch of the compiler activates a 'krunching'
-circuit that limits file names to nn characters (where nn is a decimal
+circuit that limits file names to ``nn`` characters (where ``nn`` is a decimal
integer).
-The ``gnatkr`` utility can be used to determine the krunched name for
-a given file, when krunched to a specified maximum length.
+You can use the ``gnatkr`` utility to determine the krunched name for
+a given file when krunched to a specified maximum length.
.. _Using_gnatkr:
Using ``gnatkr``
^^^^^^^^^^^^^^^^
-The ``gnatkr`` command has the form:
+You invoke the ``gnatkr`` command as follows:
.. code-block:: sh
$ gnatkr name [ length ]
``name`` is the uncrunched file name, derived from the name of the unit
-in the standard manner described in the previous section (i.e., in particular
-all dots are replaced by hyphens). The file name may or may not have an
+in the default manner described in the previous section (i.e., in particular
+all dots are replaced by hyphens). You may or may not include an
extension (defined as a suffix of the form period followed by arbitrary
-characters other than period). If an extension is present then it will
-be preserved in the output. For example, when krunching :file:`hellofile.ads`
-to eight characters, the result will be hellofil.ads.
+characters other than period) in the filename. If you do, ``gnatkr`` will
+preserve it in the output. For example, when krunching :file:`hellofile.ads`
+to eight characters, the result will be :file:`hellofil.ads`.
-Note: for compatibility with previous versions of ``gnatkr`` dots may
-appear in the name instead of hyphens, but the last dot will always be
-taken as the start of an extension. So if ``gnatkr`` is given an argument
-such as :file:`Hello.World.adb` it will be treated exactly as if the first
-period had been a hyphen, and for example krunching to eight characters
-gives the result :file:`hellworl.adb`.
+Note: for compatibility with previous versions of ``gnatkr``, you can
+use dots in the name instead of hyphens, but ``gnatkr`` always
+interprets the last dot as the start of an extension. So if you pass ``gnatkr``
+an argument such as :file:`Hello.World.adb`, it treats it
+exactly as if the first period had been a hyphen, so, for
+example, krunching to eight characters gives the result
+:file:`hellworl.adb`.
-Note that the result is always all lower case.
-Characters of the other case are folded as required.
+Note that the result is always all lower case. Other characters are
+folded as required.
``length`` represents the length of the krunched name. The default
-when no argument is given is 8 characters. A length of zero stands for
-unlimited, in other words do not chop except for system files where the
+if you don't specify it, is 8 characters. A length of zero means
+unlimited, in other words don't chop except for system files where the
implied crunching length is always eight characters.
The output is the krunched name. The output has an extension only if the
@@ -965,16 +964,16 @@ spec and ``.adb`` for a body.
Krunching does not affect the extension, but the file name is shortened to
the specified length by following these rules:
-* The name is divided into segments separated by hyphens, tildes or
+* The name is divided into segments separated by hyphens, tildes, or
underscores and all hyphens, tildes, and underscores are
eliminated. If this leaves the name short enough, we are done.
* If the name is too long, the longest segment is located (left-most
- if there are two of equal length), and shortened by dropping
+ if there are two of equal length) and shortened by dropping
its last character. This is repeated until the name is short enough.
As an example, consider the krunching of :file:`our-strings-wide_fixed.adb`
- to fit the name into 8 characters as required by some operating systems::
+ to fit the name into 8 characters, as required by some operating systems::
our-strings-wide_fixed 22
our strings wide fixed 19
@@ -1004,9 +1003,9 @@ the specified length by following these rules:
:file:`system-` :file:`s-`
===================== ==============
- These system files have a hyphen in the second character position. That
- is why normal user files replace such a character with a
- tilde, to avoid confusion with system file names.
+ These system files have a hyphen in the second character
+ position. That's is why normal user files replace such a character
+ with a tilde.
As an example of this special rule, consider
:file:`ada-strings-wide_fixed.adb`, which gets krunched as follows::
@@ -1025,10 +1024,10 @@ the specified length by following these rules:
a- st wi fi 8
Final file name: a-stwifi.adb
-Of course no file shortening algorithm can guarantee uniqueness over all
-possible unit names, and if file name krunching is used then it is your
+Of course, no file shortening algorithm can guarantee uniqueness over all
+possible unit names. If file name krunching is used, it'is your
responsibility to ensure that no name clashes occur. The utility
-program ``gnatkr`` is supplied for conveniently determining the
+program ``gnatkr`` is supplied so that you can conveniently determine the
krunched name of a file.
.. _Examples_of_gnatkr_Usage:
@@ -1054,7 +1053,7 @@ Renaming Files with ``gnatchop``
.. index:: ! gnatchop
This section discusses how to handle files with multiple units by using
-the ``gnatchop`` utility. This utility is also useful in renaming
+the ``gnatchop`` utility. You will also find this utility useful in renaming
files to meet the standard GNAT default file naming conventions.
.. _Handling_Files_with_Multiple_Units:
@@ -1062,27 +1061,28 @@ files to meet the standard GNAT default file naming conventions.
Handling Files with Multiple Units
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-The basic compilation model of GNAT requires that a file submitted to the
-compiler have only one unit and there be a strict correspondence
+GNAT's fundamental compilation model requires that a file submitted to the
+compiler contain only one unit and there be a strict correspondence
between the file name and the unit name.
-If you want to keep your files with multiple units,
+If you want to have your files contain multiple units,
perhaps to maintain compatibility with some other Ada compilation system,
-you can use ``gnatname`` to generate or update your project files.
-Generated or modified project files can be processed by GNAT.
+you can use ``gnatname`` to generate or update your project files, which
+can be processed by GNAT.
See :ref:`Handling_Arbitrary_File_Naming_Conventions_with_gnatname`
for more details on how to use `gnatname`.
-Alternatively, if you want to permanently restructure a set of 'foreign'
-files so that they match the GNAT rules, and do the remaining development
-using the GNAT structure, you can simply use ``gnatchop`` once, generate the
-new set of files and work with them from that point on.
+Alternatively, if you want to permanently restructure a set of
+'foreign' files so that they match the GNAT rules, and do the
+remaining development using the GNAT structure, you can simply use
+``gnatchop`` once, generate the new set of files containing only one
+unit per file, and work with them from that point on.
Note that if your file containing multiple units starts with a byte order
-mark (BOM) specifying UTF-8 encoding, then the files generated by gnatchop
-will each start with a copy of this BOM, meaning that they can be compiled
-automatically in UTF-8 mode without needing to specify an explicit encoding.
+mark (BOM) specifying UTF-8 encoding, each file generated by gnatchop
+will start with a copy of this BOM, meaning that they can be compiled
+automatically in UTF-8 mode without you needing to specify an explicit encoding.
.. _Operating_gnatchop_in_Compilation_Mode:
@@ -1090,27 +1090,27 @@ Operating gnatchop in Compilation Mode
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The basic function of ``gnatchop`` is to take a file with multiple units
-and split it into separate files. The boundary between files is reasonably
+and split it into separate files. The boundary between units is reasonably
clear, except for the issue of comments and pragmas. In default mode, the
rule is that any pragmas between units belong to the previous unit, except
that configuration pragmas always belong to the following unit. Any comments
belong to the following unit. These rules
almost always result in the right choice of
-the split point without needing to mark it explicitly and most users will
-find this default to be what they want. In this default mode it is incorrect to
+the split point without you needing to mark it explicitly and you'll likely
+find this default to be what you want. In this default mode, you may not
submit a file containing only configuration pragmas, or one that ends in
configuration pragmas, to ``gnatchop``.
-However, using a special option to activate 'compilation mode',
+However, using a special switch to activate 'compilation mode',
``gnatchop``
can perform another function, which is to provide exactly the semantics
-required by the RM for handling of configuration pragmas in a compilation.
-In the absence of configuration pragmas (at the main file level), this
-option has no effect, but it causes such configuration pragmas to be handled
-in a quite different manner.
+required by the RM for the handling of configuration pragmas in a compilation.
+In the absence of configuration pragmas at the main file level, this
+switch has no effect, but it causes such configuration pragmas to be handled
+in a very different manner.
-First, in compilation mode, if ``gnatchop`` is given a file that consists of
-only configuration pragmas, then this file is appended to the
+First, in compilation mode, if you give ``gnatchop`` a file that consists of
+only configuration pragmas, it appends this file to the
:file:`gnat.adc` file in the current directory. This behavior provides
the required behavior described in the RM for the actions to be taken
on submitting such a file to the compiler, namely that these pragmas
@@ -1120,14 +1120,13 @@ environment. Using GNAT, the current directory, possibly containing a
of a compilation environment. For more information on the
:file:`gnat.adc` file, see :ref:`Handling_of_Configuration_Pragmas`.
-Second, in compilation mode, if ``gnatchop``
-is given a file that starts with
-configuration pragmas, and contains one or more units, then these
-configuration pragmas are prepended to each of the chopped files. This
-behavior provides the required behavior described in the RM for the
-actions to be taken on compiling such a file, namely that the pragmas
-apply to all units in the compilation, but not to subsequently compiled
-units.
+Second, in compilation mode, if you give ``gnatchop`` a file that
+starts with configuration pragmas and contains one or more units, then
+configuration pragmas are prepended to each of the chopped
+files. This behavior provides the required behavior described in the
+RM for the actions to be taken on compiling such a file, namely that
+the pragmas apply to all units in the compilation, but not to
+subsequently compiled units.
Finally, if configuration pragmas appear between units, they are appended
to the previous unit. This results in the previous unit being illegal,
@@ -1136,12 +1135,12 @@ a unit. This provides the required RM behavior that forbids configuration
pragmas other than those preceding the first compilation unit of a
compilation.
-For most purposes, ``gnatchop`` will be used in default mode. The
-compilation mode described above is used only if you need exactly
-accurate behavior with respect to compilations, and you have files
+For most purposes, you will use ``gnatchop`` in default mode. You only
+use the compilation mode described above if you need precisely
+accurate behavior with respect to compilations and you have files
that contain multiple units and configuration pragmas. In this
-circumstance the use of ``gnatchop`` with the compilation mode
-switch provides the required behavior, and is for example the mode
+circumstance, the use of ``gnatchop`` with the compilation mode
+switch provides the required behavior. This is the mode
in which GNAT processes the ACVC tests.
@@ -1150,7 +1149,7 @@ in which GNAT processes the ACVC tests.
Command Line for ``gnatchop``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-The ``gnatchop`` command has the form:
+You call ``gnatchop`` as follows:
.. code-block:: sh
@@ -1166,7 +1165,7 @@ When run in default mode, ``gnatchop`` generates one output file in
the current directory for each unit in each of the files.
``directory``, if specified, gives the name of the directory to which
-the output files will be written. If it is not specified, all files are
+the output files will be written. If you don't specify it, all files are
written to the current directory.
For example, given a
@@ -1191,12 +1190,12 @@ the command
generates two files in the current directory, one called
:file:`hello.ads` containing the single line that is the procedure spec,
and the other called :file:`hello.adb` containing the remaining text. The
-original file is not affected. The generated files can be compiled in
+original file is not affected. You can compile these generated files in
the normal manner.
-When gnatchop is invoked on a file that is empty or that contains only empty
-lines and/or comments, gnatchop will not fail, but will not produce any
-new sources.
+When you invoke ``gnatchop`` on a file that is empty or contains only
+empty lines and/or comments, ``gnatchop`` will complete normally, but
+won't produce any new file.
For example, given a
file called :file:`toto.txt` containing
@@ -1229,25 +1228,25 @@ Switches for ``gnatchop``
.. index:: --version (gnatchop)
:switch:`--version`
- Display Copyright and version, then exit disregarding all other options.
+ Display copyright and version, then exit, disregarding all other options.
.. index:: --help (gnatchop)
:switch:`--help`
- If :switch:`--version` was not used, display usage, then exit disregarding
+ If :switch:`--version` is not present, display usage, then exit, disregarding
all other options.
.. index:: -c (gnatchop)
:switch:`-c`
Causes ``gnatchop`` to operate in compilation mode, in which
- configuration pragmas are handled according to strict RM rules. See
+ configuration pragmas are handled according to strict RM rules. See the
previous section for a full description of this mode.
:switch:`-gnat{xxx}`
- This passes the given :switch:`-gnat{xxx}` switch to ``gnat`` which is
+ This passes the given :switch:`-gnat{xxx}` switch to ``gcc`` which is
used to parse the given file. Not all *xxx* options make sense,
- but for example, the use of :switch:`-gnati2` allows ``gnatchop`` to
+ but, for example, the use of :switch:`-gnati2` allows ``gnatchop`` to
process a source file that uses Latin-2 coding for identifiers.
:switch:`-h`
@@ -1257,23 +1256,21 @@ Switches for ``gnatchop``
.. index:: -k (gnatchop)
:switch:`-k{mm}`
- Limit generated file names to the specified number ``mm``
- of characters.
- This is useful if the
- resulting set of files is required to be interoperable with systems
- which limit the length of file names.
- No space is allowed between the :switch:`-k` and the numeric value. The numeric
- value may be omitted in which case a default of :switch:`-k8`,
- suitable for use
- with DOS-like file systems, is used. If no :switch:`-k` switch
- is present then
+
+ Limit generated file names to the specified number ``mm`` of
+ characters. This is useful if the resulting set of files is
+ required to be interoperable with systems which limit the length of
+ file names. You may not place any space between the :switch:`-k`
+ and the numeric value. You can omit the numeric value, in which case
+ ``gnatchop`` will use a default of :switch:`-k8`, suitable for use
+ with DOS-like file systems. If you don't specify a :switch:`-k` switch,
there is no limit on the length of file names.
.. index:: -p (gnatchop)
:switch:`-p`
Causes the file modification time stamp of the input file to be
- preserved and used for the time stamp of the output file(s). This may be
+ preserved and used for the time stamp of the output file(s). You may find this
useful for preserving coherency of time stamps in an environment where
``gnatchop`` is used as part of a standard build process.
@@ -1288,10 +1285,10 @@ Switches for ``gnatchop``
:switch:`-r`
Generate ``Source_Reference`` pragmas. Use this switch if the output
- files are regarded as temporary and development is to be done in terms
+ files are regarded as temporary and development is to be done from
of the original unchopped file. This switch causes
``Source_Reference`` pragmas to be inserted into each of the
- generated files to refers back to the original file name and line number.
+ generated files to refer back to the original file name and line number.
The result is that all error messages refer back to the original
unchopped file.
In addition, the debugging information placed into the object file (when
@@ -1302,8 +1299,8 @@ Switches for ``gnatchop``
If the original file to be chopped itself contains
a ``Source_Reference``
- pragma referencing a third file, then gnatchop respects
- this pragma, and the generated ``Source_Reference`` pragmas
+ pragma referencing a third file, ``gnatchop`` respects these
+ pragmas and the generated ``Source_Reference`` pragmas
in the chopped file refer to the original file, with appropriate
line numbers. This is particularly useful when ``gnatchop``
is used in conjunction with ``gnatprep`` to compile files that
@@ -1312,25 +1309,27 @@ Switches for ``gnatchop``
.. index:: -v (gnatchop)
:switch:`-v`
- Causes ``gnatchop`` to operate in verbose mode. The version
- number and copyright notice are output, as well as exact copies of
- the gnat1 commands spawned to obtain the chop control information.
+ Causes ``gnatchop`` to operate in verbose mode. It outputs the
+ version number and copyright notice as well as exact copies of the
+ commands spawned to obtain the information needed to control chopping.
.. index:: -w (gnatchop)
:switch:`-w`
- Overwrite existing file names. Normally ``gnatchop`` regards it as a
- fatal error if there is already a file with the same name as a
- file it would otherwise output, in other words if the files to be
+ Overwrite existing file names. Normally, ``gnatchop`` treats it as a
+ fatal error if there's already a file with the same name as a
+ file it would otherwise output. This can happen either if you've previously
+ chopped that file or if the files to be
chopped contain duplicated units. This switch bypasses this
- check, and causes all but the last instance of such duplicated
+ check and causes all but the last instance of such duplicated
units to be skipped.
.. index:: --GCC= (gnatchop)
:switch:`--GCC={xxxx}`
Specify the path of the GNAT parser to be used. When this switch is used,
- no attempt is made to add the prefix to the GNAT parser executable.
+ ``gnatchop`` makes no attempt to add a prefix to the GNAT parser executable,
+ so it must include the full pathname.
.. _Examples_of_gnatchop_Usage:
@@ -1342,7 +1341,7 @@ Examples of ``gnatchop`` Usage
$ gnatchop -w hello_s.ada prerelease/files
-Chops the source file :file:`hello_s.ada`. The output files will be
+Chops the source file :file:`hello_s.ada`. The output files are
placed in the directory :file:`prerelease/files`,
overwriting any
files with matching names in that directory (no files in the current
@@ -1357,22 +1356,22 @@ into the current directory. One
useful application of ``gnatchop`` is in sending sets of sources
around, for example in email messages. The required sources are simply
concatenated (for example, using a Unix ``cat``
-command), and then
+command) and
``gnatchop`` is used at the other end to reconstitute the original
-file names.
+files.
.. code-block:: sh
$ gnatchop file1 file2 file3 direc
-Chops all units in files :file:`file1`, :file:`file2`, :file:`file3`, placing
-the resulting files in the directory :file:`direc`. Note that if any units
-occur more than once anywhere within this set of files, an error message
-is generated, and no files are written. To override this check, use the
-:switch:`-w` switch,
-in which case the last occurrence in the last file will
-be the one that is output, and earlier duplicate occurrences for a given
-unit will be skipped.
+Chops all units in files :file:`file1`, :file:`file2`, :file:`file3`,
+placing the resulting files in the directory :file:`direc`. Note that
+if any units occur more than once anywhere within this set of files,
+``gnatchop`` generates an error message, and doesn't write any
+files. To override this check, use the :switch:`-w` switch, in which
+case the last occurrence in the last file will be the one that is
+output and ``gnatchop`` will skip earlier duplicate occurrences for
+the same unit.
.. _Configuration_Pragmas:
@@ -1383,8 +1382,8 @@ Configuration Pragmas
.. index:: Pragmas, configuration
-Configuration pragmas include those pragmas described as
-such in the Ada Reference Manual, as well as
+Configuration pragmas supported by GNAT consist of those pragmas described as
+such in the Ada Reference Manual and the
implementation-dependent pragmas that are configuration pragmas.
See the ``Implementation_Defined_Pragmas`` chapter in the
:title:`GNAT_Reference_Manual` for details on these
@@ -1474,15 +1473,15 @@ recognized by GNAT::
Handling of Configuration Pragmas
---------------------------------
-Configuration pragmas may either appear at the start of a compilation
-unit, or they can appear in a configuration pragma file to apply to
+You can place configuration pragmas either appear at the start of a compilation
+unit or in a configuration pragma file that applies to
all compilations performed in a given compilation environment.
-GNAT also provides the ``gnatchop`` utility to provide an automatic
-way to handle configuration pragmas following the semantics for
-compilations (that is, files with multiple units), described in the RM.
+GNAT includes the ``gnatchop`` utility to provide an automatic
+way to handle configuration pragmas that follows the semantics for
+compilations (that is, files with multiple units) described in the RM.
See :ref:`Operating_gnatchop_in_Compilation_Mode` for details.
-However, for most purposes, it will be more convenient to edit the
+However, for most purposes, you will find it more convenient to edit the
:file:`gnat.adc` file that contains configuration pragmas directly,
as described in the following section.
@@ -1494,21 +1493,22 @@ Restrictions that require partition-wide consistency (like
``No_Tasking``) are
recognized wherever they appear
and can be freely inherited, e.g. from a |withed| unit to the |withing|
-unit. This makes sense since the binder will in any case insist on seeing
-consistent use, so any unit not conforming to any restrictions that are
-anywhere in the partition will be rejected, and you might as well find
-that out at compile time rather than at bind time.
+unit. This makes sense since the binder will always insist on seeing
+consistent us, so any unit not conforming to any restrictions
+anywhere in the partition will be rejected and it's better for you to find
+that out at compile time rather than bind time.
For restrictions that do not require partition-wide consistency, e.g.
-SPARK or No_Implementation_Attributes, in general the restriction applies
-only to the unit in which the pragma appears, and not to any other units.
+``SPARK`` or ``No_Implementation_Attributes``, the restriction
+normally applies only to the unit in which the pragma appears, and not
+to any other units.
-The exception is No_Elaboration_Code which always applies to the entire
-object file from a compilation, i.e. to the body, spec, and all subunits.
-This restriction can be specified in a configuration pragma file, or it
-can be on the body and/or the spec (in either case it applies to all the
-relevant units). It can appear on a subunit only if it has previously
-appeared in the body of spec.
+The exception is ``No_Elaboration_Code``, which always applies to the
+entire object file from a compilation, i.e. to the body, spec, and all
+subunits. You can apply this restriction in a configuration pragma
+file or you can ace it in the body and/or the spec (in either case it
+applies to all the relevant units). You can place it on a subunit only if
+you have previously placed it in the body of spec.
.. _The_Configuration_Pragmas_Files:
@@ -1518,33 +1518,33 @@ The Configuration Pragmas Files
.. index:: gnat.adc
-In GNAT a compilation environment is defined by the current
-directory at the time that a compile command is given. This current
-directory is searched for a file whose name is :file:`gnat.adc`. If
-this file is present, it is expected to contain one or more
-configuration pragmas that will be applied to the current compilation.
-However, if the switch :switch:`-gnatA` is used, :file:`gnat.adc` is not
-considered. When taken into account, :file:`gnat.adc` is added to the
-dependencies, so that if :file:`gnat.adc` is modified later, an invocation of
-``gnatmake`` will recompile the source.
-
-Configuration pragmas may be entered into the :file:`gnat.adc` file
-either by running ``gnatchop`` on a source file that consists only of
-configuration pragmas, or more conveniently by direct editing of the
+In GNAT, a compilation environment is defined by the current directory
+at the time that a compile command is given. This current directory is
+searched for a file whose name is :file:`gnat.adc`. If this file is
+present, it is expected to contain one or more configuration pragmas
+that will be applied to the current compilation. However, if you
+specify the switch :switch:`-gnatA`, GNAT ignores
+:file:`gnat.adc`. When used, GNAT adds :file:`gnat.adc` to the
+dependencies so that if :file:`gnat.adc` is modified later, the source
+will be recompiled on a future invocation of ``gnatmake``.
+
+You can add
+configuration pragmas into the :file:`gnat.adc` file
+either by running ``gnatchop`` on a source file consisting only of
+configuration pragmas or, more conveniently, by directly editing the
:file:`gnat.adc` file, which is a standard format source file.
-Besides :file:`gnat.adc`, additional files containing configuration
-pragmas may be applied to the current compilation using the switch
-:switch:`-gnatec={path}` where ``path`` must designate an existing file that
-contains only configuration pragmas. These configuration pragmas are
-in addition to those found in :file:`gnat.adc` (provided :file:`gnat.adc`
-is present and switch :switch:`-gnatA` is not used).
-
-It is allowable to specify several switches :switch:`-gnatec=`, all of which
-will be taken into account.
-
-Files containing configuration pragmas specified with switches
-:switch:`-gnatec=` are added to the dependencies, unless they are
+Besides :file:`gnat.adc`, you may apply additional files containing
+configuration pragmas to the current compilation using the
+:switch:`-gnatec={path}` switch, where ``path`` must designate an
+existing file that contains only configuration pragmas. These
+configuration pragmas are in addition to those found in
+:file:`gnat.adc` (provided :file:`gnat.adc` is present and you do not
+use switch :switch:`-gnatA`).
+You can specify multiple :switch:`-gnatec=` switches.
+
+GNAT will add files containing configuration pragmas specified with switches
+:switch:`-gnatec=` to the dependencies, unless they are
temporary files. A file is considered temporary if its name ends in
:file:`.tmp` or :file:`.TMP`. Certain tools follow this naming
convention because they pass information to ``gcc`` via
@@ -1552,11 +1552,11 @@ temporary files that are immediately deleted; it doesn't make sense to
depend on a file that no longer exists. Such tools include
``gprbuild``, ``gnatmake``, and ``gnatcheck``.
-By default, configuration pragma files are stored by their absolute paths in
-ALI files. You can use the :switch:`-gnateb` switch in order to store them by
-their basename instead.
+By default, configuration pragma files are stored by their absolute
+paths in ALI files. You can use the :switch:`-gnateb` switch to
+request they be stored instead by just their basename.
-If you are using project file, a separate mechanism is provided using
+If you are using project file, they provide a separate mechanism using
project attributes.
.. --Comment
@@ -1568,51 +1568,54 @@ project attributes.
Generating Object Files
=======================
-An Ada program consists of a set of source files, and the first step in
-compiling the program is to generate the corresponding object files.
-These are generated by compiling a subset of these source files.
+An Ada program consists of a set of source files and the first step in
+compiling the program is generating the corresponding object files.
+You generate these by compiling a subset of these source files.
The files you need to compile are the following:
* If a package spec has no body, compile the package spec to produce the
object file for the package.
-* If a package has both a spec and a body, compile the body to produce the
- object file for the package. The source file for the package spec need
- not be compiled in this case because there is only one object file, which
- contains the code for both the spec and body of the package.
+* If a package has both a spec and a body, compile the body to produce
+ the object file for the package. You need not compile the source
+ file for the package spec in this case because there's only one
+ object file, which contains the code for both the spec and body of
+ the package.
-* For a subprogram, compile the subprogram body to produce the object file
- for the subprogram. The spec, if one is present, is as usual in a
- separate file, and need not be compiled.
+* For a subprogram, compile the subprogram body to produce the object
+ file for the subprogram. You need not compile the spec, if such a file is
+ present.
.. index:: Subunits
-* In the case of subunits, only compile the parent unit. A single object
- file is generated for the entire subunit tree, which includes all the
- subunits.
+* In the case of subunits, only compile the parent unit. GNAT
+ generates a single object file for the entire subunit tree, which
+ includes all the subunits.
-* Compile child units independently of their parent units
- (though, of course, the spec of all the ancestor unit must be present in order
+* Compile child units independently of their parent units (though, of
+ course, the spec of all the ancestor unit must be present in order
to compile a child unit).
.. index:: Generics
-* Compile generic units in the same manner as any other units. The object
- files in this case are small dummy files that contain at most the
- flag used for elaboration checking. This is because GNAT always handles generic
- instantiation by means of macro expansion. However, it is still necessary to
- compile generic units, for dependency checking and elaboration purposes.
+* Compile generic units in the same manner as any other units. The
+ object files in this case are small dummy files that contain, at
+ most, the flag used for elaboration checking. This is because GNAT
+ always handles generic instantiation by means of macro
+ expansion. However, you still must compile generic units
+ for dependency checking and elaboration purposes.
The preceding rules describe the set of files that must be compiled to
-generate the object files for a program. Each object file has the same
+generate all the object files for a program. See the following section on dependencies for more details on computing that set of files.
+Each object file has the same
name as the corresponding source file, except that the extension is
-:file:`.o` as usual.
+:file:`.o`, as usual.
You may wish to compile other files for the purpose of checking their
syntactic and semantic correctness. For example, in the case where a
package has a separate spec and body, you would not normally compile the
spec. However, it is convenient in practice to compile the spec to make
-sure it is error-free before compiling clients of this spec, because such
+sure it is error-free before compiling clients of this spec because such
compilations will fail if there is an error in the spec.
GNAT provides an option for compiling such files purely for the
@@ -1625,18 +1628,17 @@ checking mode, use the :switch:`-gnatc` switch.
Source Dependencies
===================
-A given object file clearly depends on the source file which is compiled
-to produce it. Here we are using "depends" in the sense of a typical
-``make`` utility; in other words, an object file depends on a source
-file if changes to the source file require the object file to be
-recompiled.
-In addition to this basic dependency, a given object may depend on
-additional source files as follows:
+Each object file obviously depends on at least the source file which
+is compiled to produce it. Here we are using "depends" in the sense of
+a typical ``make`` utility; in other words, an object file depends on
+a source file if changes to the source file require the object file to
+be recompiled. In addition to this basic dependency, a given object
+may depend on additional source files as follows:
* If a file being compiled |withs| a unit ``X``, the object file
depends on the file containing the spec of unit ``X``. This includes
files that are |withed| implicitly either because they are parents
- of |withed| child units or they are run-time units required by the
+ of |withed| child units or are run-time units required by the
language constructs used in a particular unit.
* If a file being compiled instantiates a library level generic unit, the
@@ -1651,11 +1653,11 @@ additional source files as follows:
.. index:: -gnatn switch
* If a file being compiled contains a call to a subprogram for which
- pragma ``Inline`` applies and inlining is activated with the
+ pragma ``Inline`` applies and you have activated inlining with the
:switch:`-gnatn` switch, the object file depends on the file containing the
body of this subprogram as well as on the file containing the spec. Note
that for inlining to actually occur as a result of the use of this switch,
- it is necessary to compile in optimizing mode.
+ you must compile in optimizing mode.
.. index:: -gnatN switch
@@ -1664,9 +1666,9 @@ additional source files as follows:
not require that the code generation be optimized. Like :switch:`-gnatn`,
the use of this switch generates additional dependencies.
- When using a gcc-based back end, then the use of
- :switch:`-gnatN` is deprecated, and the use of :switch:`-gnatn` is preferred.
- Historically front end inlining was more extensive than the gcc back end
+ When using a ``gcc`` or LLVM based back end, the use of
+ :switch:`-gnatN` is deprecated and the use of :switch:`-gnatn` is preferred.
+ Historically front end inlining was more extensive than back end
inlining, but that is no longer the case.
* If an object file :file:`O` depends on the proper body of a subunit through
@@ -1676,12 +1678,13 @@ additional source files as follows:
* The object file for a parent unit depends on all its subunit body files.
-* The previous two rules meant that for purposes of computing dependencies and
- recompilation, a body and all its subunits are treated as an indivisible whole.
+* The previous two rules means that, for purposes of computing
+ dependencies and recompilation, a body and all its subunits are
+ treated as an indivisible whole.
These rules are applied transitively: if unit ``A`` |withs|
unit ``B``, whose elaboration calls an inlined procedure in package
- ``C``, the object file for unit ``A`` will depend on the body of
+ ``C``, the object file for unit ``A`` depends on the body of
``C``, in file :file:`c.adb`.
The set of dependent files described by these rules includes all the
@@ -1690,13 +1693,13 @@ additional source files as follows:
standard describes, because it includes generic, inline, and subunit
dependencies.
- An object file must be recreated by recompiling the corresponding source
- file if any of the source files on which it depends are modified. For
- example, if the ``make`` utility is used to control compilation,
- the rule for an Ada object file must mention all the source files on
- which the object file depends, according to the above definition.
- The determination of the necessary
- recompilations is done automatically when one uses ``gnatmake``.
+ An object file must be recreated by recompiling the corresponding
+ source file if any of the source files on which it depends are
+ modified. For example, if the ``make`` utility is used to control
+ compilation, the rule for an Ada object file must mention all the
+ source files on which the object file depends, according to the
+ above definition. Invoking ``gnatmake`` will cause it to determine
+ the necessary recompilations.
.. _The_Ada_Library_Information_Files:
@@ -1708,11 +1711,11 @@ The Ada Library Information Files
.. index:: ALI files
Each compilation actually generates two output files. The first of these
-is the normal object file that has a :file:`.o` extension. The second is a
+is the actual object file that has a :file:`.o` extension. The second is a
text file containing full dependency information. It has the same
name as the source file, but an :file:`.ali` extension.
This file is known as the Ada Library Information (:file:`ALI`) file.
-The following information is contained in the :file:`ALI` file.
+The following information is contained in that file:
* Version information (indicates which version of GNAT was used to compile
the unit(s) in question)
@@ -1720,13 +1723,14 @@ The following information is contained in the :file:`ALI` file.
* Main program information (including priority and time slice settings,
as well as the wide character encoding used during compilation).
-* List of arguments used in the ``gcc`` command for the compilation
+* List of arguments used in the compilation command
-* Attributes of the unit, including configuration pragmas used, an indication
- of whether the compilation was successful, exception model used etc.
+* Attributes of the unit, including the configuration pragmas used, an
+ indication of whether the compilation was successful, and the exception
+ model used.
-* A list of relevant restrictions applying to the unit (used for consistency)
- checking.
+* A list of relevant restrictions applying to the unit (used for consistency
+ checking).
* Categorization information (e.g., use of pragma ``Pure``).
@@ -1740,8 +1744,8 @@ The following information is contained in the :file:`ALI` file.
* Dependency information. This is a list of files, together with
time stamp and checksum information. These are files on which
- the unit depends in the sense that recompilation is required
- if any of these units are modified.
+ the unit depends in the sense that the modification of any of
+ these units requires the recompilation of the unit in question.
* Cross-reference data. Contains information on all entities referenced
in the unit. Used by some tools to provide cross-reference information.
@@ -1758,7 +1762,7 @@ Binding an Ada Program
When using languages such as C and C++, once the source files have been
compiled the only remaining step in building an executable program
-is linking the object modules together. This means that it is possible to
+is linking the object modules together. This means that you can
link an inconsistent version of a program, in which two units have
included different versions of the same header.
@@ -1769,13 +1773,13 @@ These rules are enforced by the GNAT binder, which also determines an
elaboration order consistent with the Ada rules.
The GNAT binder is run after all the object files for a program have
-been created. It is given the name of the main program unit, and from
-this it determines the set of units required by the program, by reading the
+been created. It is given the name of the main program unit and from
+this determines the set of units required by the program by reading the
corresponding ALI files. It generates error messages if the program is
inconsistent or if no valid order of elaboration exists.
-If no errors are detected, the binder produces a main program, in Ada by
-default, that contains calls to the elaboration procedures of those
+If no errors are detected, the binder produces a main program in Ada
+that contains calls to the elaboration procedures of those
compilation unit that require them, followed by
a call to the main program. This Ada program is compiled to generate the
object file for the main program. The name of
@@ -1793,12 +1797,12 @@ object files for the Ada units of the program.
GNAT and Libraries
==================
-.. index:: Library building and using
+.. index:: Library building and referencing
-This section describes how to build and use libraries with GNAT, and also shows
+This section describes how to build and use libraries with GNAT and
how to recompile the GNAT run-time library. You should be familiar with the
Project Manager facility (see the *GNAT_Project_Manager* chapter of the
-*GPRbuild User's Guide*) before reading this chapter.
+:title:`GPRbuild User's Guide`) before reading this chapter.
.. _Introduction_to_Libraries_in_GNAT:
@@ -1806,30 +1810,30 @@ Introduction to Libraries in GNAT
---------------------------------
A library is, conceptually, a collection of objects which does not have its
-own main thread of execution, but rather provides certain services to the
+own main thread of execution but instead provides certain services to the
applications that use it. A library can be either statically linked with the
application, in which case its code is directly included in the application,
or, on platforms that support it, be dynamically linked, in which case
its code is shared by all applications making use of this library.
GNAT supports both types of libraries.
-In the static case, the compiled code can be provided in different ways. The
-simplest approach is to provide directly the set of objects resulting from
+In the static case, you can provide the compiled code in different ways. The
+simplest approach is to directly provide the set of objects resulting from
compilation of the library source files. Alternatively, you can group the
objects into an archive using whatever commands are provided by the operating
-system. For the latter case, the objects are grouped into a shared library.
+system.
-In the GNAT environment, a library has three types of components:
+In the GNAT environment, a library has these components:
* Source files,
* :file:`ALI` files (see :ref:`The_Ada_Library_Information_Files`), and
-* Object files, an archive or a shared library.
+* Object files, an archive, or a shared library.
A GNAT library may expose all its source files, which is useful for
documentation purposes. Alternatively, it may expose only the units needed by
-an external user to make use of the library. That is to say, the specs
+an external user to make use of the library, in other words, the specs
reflecting the library services along with all the units needed to compile
those specs, which can include generic bodies or any body implementing an
inlined routine. In the case of *stand-alone libraries* those exposed
@@ -1857,19 +1861,18 @@ Building a library
The easiest way to build a library is to use the Project Manager,
which supports a special type of project called a *Library Project*
(see the *Library Projects* section in the *GNAT Project Manager*
-chapter of the *GPRbuild User's Guide*).
+chapter of the :title:`GPRbuild User's Guide`).
-A project is considered a library project, when two project-level attributes
-are defined in it: ``Library_Name`` and ``Library_Dir``. In order to
-control different aspects of library configuration, additional optional
-project-level attributes can be specified:
+A project is considered a library project when two project-level
+attributes are defined in it: ``Library_Name`` and ``Library_Dir``. In
+order to control different aspects of library configuration, you can
+specify additional optional project-level attributes:
* ``Library_Kind``
This attribute controls whether the library is to be static or dynamic
-
* ``Library_Version``
- This attribute specifies the library version; this value is used
+ This attribute specifies the library version. Its value is used
during dynamic linking of shared libraries to determine if the currently
installed versions of the binaries are compatible.
@@ -1877,16 +1880,16 @@ project-level attributes can be specified:
* ``Library_GCC``
These attributes specify additional low-level options to be used during
- library generation, and redefine the actual application used to generate
+ library generation and the commands used to generate the
library.
-The GNAT Project Manager takes full care of the library maintenance task,
+The GNAT Project Manager takes complete care of the library maintenance task,
including recompilation of the source files for which objects do not exist
or are not up to date, assembly of the library archive, and installation of
the library (i.e., copying associated source, object and :file:`ALI` files
to the specified location).
-Here is a simple library project file:
+Here's a simple library project file:
.. code-block:: gpr
@@ -1904,22 +1907,23 @@ and the compilation command to build and install the library:
$ gnatmake -Pmy_lib
-It is not entirely trivial to perform manually all the steps required to
-produce a library. We recommend that you use the GNAT Project Manager
-for this task. In special cases where this is not desired, the necessary
-steps are discussed below.
+It's complex to manually perform all the steps required to
+produce a library, so we recommend you use the GNAT Project Manager
+for this task. In case this is not desired, we discuss the necessary
+steps below.
-There are various possibilities for compiling the units that make up the
-library: for example with a Makefile (:ref:`Using_the_GNU_make_Utility`) or
-with a conventional script. For simple libraries, it is also possible to create
-a dummy main program which depends upon all the packages that comprise the
-interface of the library. This dummy main program can then be given to
-``gnatmake``, which will ensure that all necessary objects are built.
+There are various possibilities for compiling the units that make up
+the library: for example with a :file:`Makefile`
+(:ref:`Using_the_GNU_make_Utility`) or with a conventional script. For
+simple libraries, you can also create a dummy main program
+that depends upon all the packages that comprise the interface of the
+library. You can then pass this dummy main program to ``gnatmake``,
+which will ensure all necessary objects are built.
-After this task is accomplished, you should follow the standard procedure
+After the above has been accomplished, you should follow the standard procedure
of the underlying operating system to produce the static or shared library.
-Here is an example of such a dummy program:
+Here's an example of such a dummy program:
.. code-block:: ada
@@ -1958,7 +1962,7 @@ Here are the generic commands that will build an archive or a shared library.
Please note that the library must have a name of the form :file:`lib{xxx}.a`
or :file:`lib{xxx}.so` (or :file:`lib{xxx}.dll` on Windows) in order to
-be accessed by the directive :switch:`-l{xxx}` at link time.
+be accessed by the :switch:`-l{xxx}` switch at link time.
.. _Installing_a_library:
@@ -1970,17 +1974,19 @@ Installing a library
If you use project files, library installation is part of the library build
process (see the *Installing a Library with Project Files* section of the
-*GNAT Project Manager* chapter of the *GPRbuild User's Guide*).
-
-When project files are not an option, it is also possible, but not recommended,
-to install the library so that the sources needed to use the library are on the
-Ada source path and the ALI files & libraries be on the Ada Object path (see
-:ref:`Search_Paths_and_the_Run-Time_Library_RTL`). Alternatively, the system
-administrator can place general-purpose libraries in the default compiler
-paths, by specifying the libraries' location in the configuration files
-:file:`ada_source_path` and :file:`ada_object_path`. These configuration files
-must be located in the GNAT installation tree at the same place as the gcc spec
-file. The location of the gcc spec file can be determined as follows:
+*GNAT Project Manager* chapter of the :title:`GPRbuild User's Guide`).
+
+When you're not able to use project files for some reason, you can
+also install the library so that the sources needed to use the library
+are on the Ada source path and the ALI files & libraries be on the Ada
+Object path (see :ref:`Search_Paths_and_the_Run-Time_Library_RTL`),
+but we don't recommend doing this. Alternatively, the system
+administrator can place general-purpose libraries in the default
+compiler paths, by specifying the libraries' location in the
+configuration files :file:`ada_source_path` and
+:file:`ada_object_path`. These configuration files must be located in
+the GNAT installation tree at the same place as the ``gcc`` spec
+file. The location of the ``gcc`` spec file can be determined as follows:
.. code-block:: sh
@@ -1996,7 +2002,7 @@ are located.
The files :file:`ada_source_path` and :file:`ada_object_path` might not be
present in a
-GNAT installation, in which case, GNAT will look for its run-time library in
+GNAT installation, in which case, GNAT looks for its run-time library in
the directories :file:`adainclude` (for the sources) and :file:`adalib` (for the
objects and :file:`ALI` files). When the files exist, the compiler does not
look in :file:`adainclude` and :file:`adalib`, and thus the
@@ -2006,16 +2012,16 @@ be :file:`adainclude`). In the same way, the :file:`ada_object_path` file must
contain the location for the GNAT run-time objects (which can simply
be :file:`adalib`).
-You can also specify a new default path to the run-time library at compilation
-time with the switch :switch:`--RTS=rts-path`. You can thus choose / change
-the run-time library you want your program to be compiled with. This switch is
-recognized by ``gcc``, ``gnatmake``, ``gnatbind``, ``gnatls``, and all
-project aware tools.
+You can also specify a new default path to the run-time library at
+compilation time with the :switch:`--RTS=rts-path` switch. You can
+thus choose the run-time library you want your program to be
+compiled with. This switch is recognized by ``gcc``, ``gnatmake``,
+``gnatbind``, ``gnatls``, and all project aware tools.
-It is possible to install a library before or after the standard GNAT
-library, by reordering the lines in the configuration files. In general, a
-library must be installed before the GNAT library if it redefines
-any part of it.
+You can install a library before or after the standard GNAT library by
+selecting the ordering the lines in the configuration files. In
+general, a library must be installed before the GNAT library if it
+redefines any part of it.
.. _Using_a_library:
@@ -2024,7 +2030,7 @@ Using a library
Once again, the project facility greatly simplifies the use of
libraries. In this context, using a library is just a matter of adding a
-|with| clause in the user project. For instance, to make use of the
+|with| clause in your project. For example, to make use of the
library ``My_Lib`` shown in examples in earlier sections, you can
write:
@@ -2110,28 +2116,25 @@ Stand-alone Ada Libraries
Introduction to Stand-alone Libraries
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-A Stand-alone Library (abbreviated 'SAL') is a library that contains the
-necessary code to
-elaborate the Ada units that are included in the library. In contrast with
-an ordinary library, which consists of all sources, objects and :file:`ALI`
-files of the
-library, a SAL may specify a restricted subset of compilation units
-to serve as a library interface. In this case, the fully
-self-sufficient set of files will normally consist of an objects
-archive, the sources of interface units' specs, and the :file:`ALI`
-files of interface units.
-If an interface spec contains a generic unit or an inlined subprogram,
-the body's
-source must also be provided; if the units that must be provided in the source
-form depend on other units, the source and :file:`ALI` files of those must
-also be provided.
+A Stand-alone Library (abbreviated 'SAL') is a library that contains
+the necessary code to elaborate the Ada units that are included in the
+library. In contrast with an ordinary library, which consists of all
+sources, objects and :file:`ALI` files of the library, a SAL may
+specify a restricted subset of compilation units to serve as a library
+interface. In this case, the fully self-sufficient set of files will
+normally consist of an objects archive, the sources of interface
+units' specs, and the :file:`ALI` files of interface units. If an
+interface spec contains a generic unit or an inlined subprogram, you
+must also provide the body's source; if the units that must be
+provided in the source form depend on other units, you must also
+provide the source and :file:`ALI` files of those units.
The main purpose of a SAL is to minimize the recompilation overhead of client
applications when a new version of the library is installed. Specifically,
-if the interface sources have not changed, client applications do not need to
+if the interface sources have not changed, client applications don't need to
be recompiled. If, furthermore, a SAL is provided in the shared form and its
version, controlled by ``Library_Version`` attribute, is not changed,
-then the clients do not need to be relinked.
+the clients also do not need to be relinked.
SALs also allow the library providers to minimize the amount of library source
text exposed to the clients. Such 'information hiding' might be useful or
@@ -2147,12 +2150,12 @@ Building a Stand-alone Library
GNAT's Project facility provides a simple way of building and installing
stand-alone libraries; see the *Stand-alone Library Projects* section
-in the *GNAT Project Manager* chapter of the *GPRbuild User's Guide*.
+in the *GNAT Project Manager* chapter of the :title:`GPRbuild User's Guide`.
To be a Stand-alone Library Project, in addition to the two attributes
that make a project a Library Project (``Library_Name`` and
``Library_Dir``; see the *Library Projects* section in the
*GNAT Project Manager* chapter of the *GPRbuild User's Guide*),
-the attribute ``Library_Interface`` must be defined. For example:
+you must define the attribute ``Library_Interface``. For example:
.. code-block:: gpr
@@ -2164,7 +2167,7 @@ Attribute ``Library_Interface`` has a non-empty string list value,
each string in the list designating a unit contained in an immediate source
of the project file.
-When a Stand-alone Library is built, first the binder is invoked to build
+When a Stand-alone Library is built, the binder is first invoked to build
a package whose name depends on the library name
(:file:`b~dummy.ads/b` in the example above).
This binder-generated package includes initialization and
@@ -2185,13 +2188,13 @@ the Library Directory. As a consequence, only the Interface Units may be
imported from Ada units outside of the library. If other units are imported,
the binding phase will fail.
-It is also possible to build an encapsulated library where not only
+You can also build an encapsulated library where not only
the code to elaborate and finalize the library is embedded but also
-ensuring that the library is linked only against static
-libraries. So an encapsulated library only depends on system
-libraries, all other code, including the GNAT runtime, is embedded. To
-build an encapsulated library the attribute
-``Library_Standalone`` must be set to ``encapsulated``:
+ensure that the library is linked only against static
+libraries. That means that an encapsulated library only depends on system
+libraries: all other code, including the GNAT runtime, is embedded. To
+build an encapsulated library you must set attribute
+``Library_Standalone`` to ``encapsulated``:
.. code-block:: gpr
@@ -2204,19 +2207,20 @@ build an encapsulated library the attribute
The default value for this attribute is ``standard`` in which case
a stand-alone library is built.
-The attribute ``Library_Src_Dir`` may be specified for a
-Stand-Alone Library. ``Library_Src_Dir`` is a simple attribute that has a
-single string value. Its value must be the path (absolute or relative to the
-project directory) of an existing directory. This directory cannot be the
-object directory or one of the source directories, but it can be the same as
-the library directory. The sources of the Interface
-Units of the library that are needed by an Ada client of the library will be
-copied to the designated directory, called the Interface Copy directory.
-These sources include the specs of the Interface Units, but they may also
-include bodies and subunits, when pragmas ``Inline`` or ``Inline_Always``
-are used, or when there is a generic unit in the spec. Before the sources
-are copied to the Interface Copy directory, an attempt is made to delete all
-files in the Interface Copy directory.
+You may specify the attribute ``Library_Src_Dir`` for a Stand-Alone
+Library. ``Library_Src_Dir`` has a single string value. Its value must
+be the path (absolute or relative to the project directory) of an
+existing directory. This directory cannot be the object directory or
+one of the source directories, but it can be the same as the library
+directory. The sources of the Interface Units of the library that are
+needed by an Ada client of the library are copied to the designated
+directory, called the Interface Copy directory, when the library is
+built. These sources include the specs of the Interface Units, but
+they may also include bodies and subunits when pragmas ``Inline`` or
+``Inline_Always`` are used or when there is a generic unit in the
+spec. Before the sources are copied to the Interface Copy directory,
+the building process makes an attempt to delete all files in the
+Interface Copy directory.
Building stand-alone libraries by hand is somewhat tedious, but for those
occasions when it is necessary here are the steps that you need to perform:
@@ -2239,10 +2243,10 @@ occasions when it is necessary here are the steps that you need to perform:
$ gcc -c b~int2.adb
* Link the dynamic library with all the necessary object files,
- indicating to the linker the names of the ``init`` (and possibly
+ passing to the linker the names of the ``init`` (and possibly
``final``) procedures for automatic initialization (and finalization).
- The built library should be placed in a directory different from
- the object directory.
+ You should place the built library in a different directory than
+ the object files.
* Copy the ``ALI`` files of the interface to the library directory,
add in this copy an indication that it is an interface to a SAL
@@ -2258,14 +2262,14 @@ Using SALs is not different from using other libraries
Creating a Stand-alone Library to be used in a non-Ada context
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-It is easy to adapt the SAL build procedure discussed above for use of a SAL in
-a non-Ada context.
+It's easy for you to adapt the SAL build procedure discussed above for
+use of a SAL in a non-Ada context.
The only extra step required is to ensure that library interface subprograms
are compatible with the main program, by means of ``pragma Export``
or ``pragma Convention``.
-Here is an example of simple library interface for use with C main program:
+Here's an example of simple library interface for use with C main program:
.. code-block:: ada
@@ -2279,7 +2283,7 @@ Here is an example of simple library interface for use with C main program:
end My_Package;
-On the foreign language side, you must provide a 'foreign' view of the
+On the C side, you must provide a 'foreign' view of the
library interface; remember that it should contain elaboration routines in
addition to interface subprograms.
@@ -2299,9 +2303,9 @@ that there is no rule for the naming of this file, any name can be used)
extern void do_something_else (void);
Libraries built as explained above can be used from any program, provided
-that the elaboration procedures (named ``mylibinit`` in the previous
-example) are called before the library services are used. Any number of
-libraries can be used simultaneously, as long as the elaboration
+the elaboration procedures (named ``mylibinit`` in the previous
+example) are called before any library services are used. Any number of
+libraries can be called from a single executable as long as the elaboration
procedure of each library is called.
Below is an example of a C program that uses the ``mylib`` library.
@@ -2335,19 +2339,20 @@ after the finalization phase.
Information on limitations of binding Ada code in non-Ada contexts can be
found under :ref:`Binding_with_Non-Ada_Main_Programs`.
-Note also that special care must be taken with multi-tasks
-applications. The initialization and finalization routines are not
-protected against concurrent access. If such requirement is needed it
-must be ensured at the application level using a specific operating
-system services like a mutex or a critical-section.
+Note also that you must take special care with multi-tasking
+applications. In that case, the initialization and finalization
+routines are not protected against concurrent access. If you need such
+requirement, you must ensure it at the application level
+using a specific operating system services like a mutex or a
+critical-section.
.. _Restrictions_in_Stand-alone_Libraries:
Restrictions in Stand-alone Libraries
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-The pragmas listed below should be used with caution inside libraries,
-as they can create incompatibilities with other Ada libraries:
+You should use the pragmas listed below with caution inside libraries,
+since they can create incompatibilities with other Ada libraries:
* pragma ``Locking_Policy``
* pragma ``Partition_Elaboration_Policy``
@@ -2355,22 +2360,21 @@ as they can create incompatibilities with other Ada libraries:
* pragma ``Task_Dispatching_Policy``
* pragma ``Unreserve_All_Interrupts``
-When using a library that contains such pragmas, the user must make sure
-that all libraries use the same pragmas with the same values. Otherwise,
-``Program_Error`` will
-be raised during the elaboration of the conflicting
-libraries. The usage of these pragmas and its consequences for the user
-should therefore be well documented.
+When using a library that contains such pragmas, the user of the
+library must ensure that all libraries use the same pragmas with the
+same values. Otherwise, ``Program_Error`` will be raised during the
+elaboration of the conflicting libraries. You should document the
+usage of these pragmas and its consequences for the user.
Similarly, the traceback in the exception occurrence mechanism should be
enabled or disabled in a consistent manner across all libraries.
-Otherwise, Program_Error will be raised during the elaboration of the
+Otherwise, ``Program_Error`` will be raised during the elaboration of the
conflicting libraries.
-If the ``Version`` or ``Body_Version``
-attributes are used inside a library, then you need to
+If you use the ``Version`` or ``Body_Version``
+attributes inside a library, you need to
perform a ``gnatbind`` step that specifies all :file:`ALI` files in all
-libraries, so that version identifiers can be properly computed.
+libraries so that version identifiers can be properly computed.
In practice these attributes are rarely used, so this is unlikely
to be a consideration.
@@ -2384,25 +2388,25 @@ Rebuilding the GNAT Run-Time Library
.. index:: Rebuilding the GNAT Run-Time Library
.. index:: Run-Time Library, rebuilding
-It may be useful to recompile the GNAT library in various debugging or
-experimentation contexts. A project file called
-:file:`libada.gpr` is provided to that effect and can be found in
-the directory containing the GNAT library. The location of this
-directory depends on the way the GNAT environment has been installed and can
-be determined by means of the command:
+You may need to recompile the GNAT library in various debugging or
+experimentation contexts. The GNAT distribution provides a project
+file called :file:`libada.gpr` to do that; it can be found in the
+directory containing the GNAT library. The location of this directory
+depends on the way the GNAT environment has been installed and can be
+determined by means of the command:
.. code-block:: sh
$ gnatls -v
The last entry in the source search path usually contains the
-gnat library (the :file:`adainclude` directory). This project file contains its
-own documentation and in particular the set of instructions needed to rebuild a
-new library and to use it.
+GNAT library (the :file:`adainclude` directory).
-Note that rebuilding the GNAT Run-Time is only recommended for temporary
-experiments or debugging, and is not supported.
+This project file contains its own documentation and, in particular, the
+set of instructions needed to rebuild a new library and to use it.
+Note that rebuilding the GNAT Run-Time is only recommended for temporary
+experiments or debugging and is not supported for other purposes.
.. index:: ! Conditional compilation
@@ -2421,7 +2425,7 @@ gnatprep preprocessor utility.
Modeling Conditional Compilation in Ada
---------------------------------------
-It is often necessary to arrange for a single source program
+You may want to arrange for a single source program
to serve multiple purposes, where it is compiled in different
ways to achieve these different goals. Some examples of the
need for this feature are
@@ -2431,21 +2435,21 @@ need for this feature are
* Turning debugging features on and off
* Arranging for a program to compile with different compilers
-In C, or C++, the typical approach would be to use the preprocessor
-that is defined as part of the language. The Ada language does not
+In C, or C++, the typical approach is to use the preprocessor
+defined as part of the language. The Ada language does not
contain such a feature. This is not an oversight, but rather a very
deliberate design decision, based on the experience that overuse of
the preprocessing features in C and C++ can result in programs that
are extremely difficult to maintain. For example, if we have ten
switches that can be on or off, this means that there are a thousand
separate programs, any one of which might not even be syntactically
-correct, and even if syntactically correct, the resulting program
+correct, and, even if syntactically correct,
might not work correctly. Testing all combinations can quickly become
impossible.
-Nevertheless, the need to tailor programs certainly exists, and in
+Nevertheless, the need to tailor programs certainly exists and in
this section we will discuss how this can
-be achieved using Ada in general, and GNAT in particular.
+be achieved using Ada in general and GNAT in particular.
.. _Use_of_Boolean_Constants:
@@ -2467,7 +2471,7 @@ constants to control which code is executed.
Not only will the code inside the ``if`` statement not be executed if
the constant Boolean is ``False``, but it will also be completely
deleted from the program.
-However, the code is only deleted after the ``if`` statement
+However, the code is only deleted after the ``if`` statement block
has been checked for syntactic and semantic correctness.
(In contrast, with preprocessors the code is deleted before the
compiler ever gets to see it, so it is not checked until the switch
@@ -2486,9 +2490,9 @@ something like:
...
end Config;
-The ``Config`` package exists in multiple forms for the various targets,
+You would write the ``Config`` package multiple forms for various targets,
with an appropriate script selecting the version of ``Config`` needed.
-Then any other unit requiring conditional compilation can do a |with|
+Then, any other unit requiring conditional compilation can do a |with|
of ``Config`` to make the constants visible.
.. _Debugging_-_A_Special_Case:
@@ -2499,7 +2503,7 @@ Debugging - A Special Case
A common use of conditional code is to execute statements (for example
dynamic checks, or output of intermediate results) under control of a
debug switch, so that the debugging behavior can be turned on and off.
-This can be done using a Boolean constant to control whether the code
+You can do this by using a Boolean constant to control whether the debug code
is active:
.. code-block:: ada
@@ -2518,14 +2522,14 @@ or
.. index:: pragma Assert
-Since this is a common case, there are special features to deal with
-this in a convenient manner. For the case of tests, Ada 2005 has added
-a pragma ``Assert`` that can be used for such tests. This pragma is modeled
-on the ``Assert`` pragma that has always been available in GNAT, so this
-feature may be used with GNAT even if you are not using Ada 2005 features.
-The use of pragma ``Assert`` is described in the
-:title:`GNAT_Reference_Manual`, but as an
-example, the last test could be written:
+Since this is a common case, GNAT provides special features to deal
+with this in a convenient manner. For the case of tests, Ada 2005 has
+added a pragma ``Assert`` that you can use for such tests. This pragma
+is modeled on the ``Assert`` pragma that has always been available in
+GNAT, so you can use this feature with GNAT even if you are not using
+Ada 2005 features. The use of pragma ``Assert`` is described in the
+:title:`GNAT_Reference_Manual`, but as an example, the last test could
+be written:
.. code-block:: ada
@@ -2537,10 +2541,10 @@ or simply
pragma Assert (Temperature <= 999.0);
-In both cases, if assertions are active and the temperature is excessive,
-the exception ``Assert_Failure`` will be raised, with the given string in
-the first case or a string indicating the location of the pragma in the second
-case used as the exception message.
+In both cases, if assertions are active and the temperature is
+excessive, the exception ``Assert_Failure`` is raised with the
+exception message using the specified string in the first case or a
+string indicating the location of the pragma in the second case.
.. index:: pragma Assertion_Policy
@@ -2549,9 +2553,9 @@ pragma.
.. index:: -gnata switch
-This is an Ada 2005 pragma which is implemented in all modes by
+This is an Ada 2005 pragma that is implemented in all modes by
GNAT. Alternatively, you can use the :switch:`-gnata` switch
-to enable assertions from the command line, which applies to
+to enable assertions from the command line, which also applies to
all versions of Ada.
.. index:: pragma Debug
@@ -2563,11 +2567,11 @@ For the example above with the ``Put_Line``, the GNAT-specific pragma
pragma Debug (Put_Line ("got to the first stage!"));
-If debug pragmas are enabled, the argument, which must be of the form of
-a procedure call, is executed (in this case, ``Put_Line`` will be called).
-Only one call can be present, but of course a special debugging procedure
-containing any code you like can be included in the program and then
-called in a pragma ``Debug`` argument as needed.
+If debug pragmas are enabled, the argument, which must be of the form
+of a procedure call, is executed (in this case, ``Put_Line`` is
+called). You can specify only one call, but you can of course include
+a special debugging procedure containing any code you like in the
+program and call it in a pragma ``Debug`` argument as needed.
One advantage of pragma ``Debug`` over the ``if Debugging then``
construct is that pragma ``Debug`` can appear in declarative contexts,
@@ -2576,16 +2580,16 @@ been elaborated.
.. index:: pragma Debug_Policy
-Debug pragmas are enabled using either the :switch:`-gnata` switch that also
+You can enable debug pragmas using either the :switch:`-gnata` switch that also
controls assertions, or with a separate Debug_Policy pragma.
The latter pragma is new in the Ada 2005 versions of GNAT (but it can be used
-in Ada 95 and Ada 83 programs as well), and is analogous to
+in Ada 95 and Ada 83 programs as well) and is analogous to
pragma ``Assertion_Policy`` to control assertions.
``Assertion_Policy`` and ``Debug_Policy`` are configuration pragmas,
-and thus they can appear in :file:`gnat.adc` if you are not using a
-project file, or in the file designated to contain configuration pragmas
+and thus can appear in :file:`gnat.adc` if you are not using a
+project file or in the file designated to contain configuration pragmas
in a project file.
They then apply to all subsequent compilations. In practice the use of
the :switch:`-gnata` switch is often the most convenient method of controlling
@@ -2666,7 +2670,7 @@ for the little endian case. Since a powerful subset of Ada expression
notation is usable for creating static constants, clever use of this
feature can often solve quite difficult problems in conditionalizing
compilation (note incidentally that in Ada 95, the little endian
-constant was introduced as ``System.Default_Bit_Order``, so you do not
+constant was introduced as ``System.Default_Bit_Order``, so you don't
need to define this one yourself).
.. _Use_of_Alternative_Implementations:
@@ -2675,16 +2679,16 @@ Use of Alternative Implementations
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
In some cases, none of the approaches described above are adequate. This
-can occur for example if the set of declarations required is radically
+can occur, for example, if the set of declarations required is radically
different for two different configurations.
In this situation, the official Ada way of dealing with conditionalizing
such code is to write separate units for the different cases. As long as
-this does not result in excessive duplication of code, this can be done
+this doesn't result in excessive duplication of code, you can do this
without creating maintenance problems. The approach is to share common
-code as far as possible, and then isolate the code and declarations
+code as far as possible and then isolate the code and declarations
that are different. Subunits are often a convenient method for breaking
-out a piece of a unit that is to be conditionalized, with separate files
+out a piece of a unit that you need to be conditionalized, with separate files
for different versions of the subunit for different targets, where the
build script selects the right one to give to the compiler.
@@ -2708,9 +2712,9 @@ But this won't work when ``Ada_2005`` is set to ``False``,
since the ``then`` clause will be illegal for an Ada 95 compiler.
(Recall that although such unreachable code would eventually be deleted
by the compiler, it still needs to be legal. If it uses features
-introduced in Ada 2005, it will be illegal in Ada 95.)
+introduced in Ada 2005, it's still illegal in Ada 95.)
-So instead we write
+So instead, we write
.. code-block:: ada
@@ -2732,9 +2736,9 @@ This can also be done with project files' naming schemes. For example:
for body ("File_Queries.Insert") use "file_queries-insert-2005.ada";
-Note also that with project files it is desirable to use a different extension
-than :file:`ads` / :file:`adb` for alternative versions. Otherwise a naming
-conflict may arise through another commonly used feature: to declare as part
+Note also that with project files, you should use a different extension
+than :file:`ads` / :file:`adb` for alternative versions. Otherwise, a naming
+conflict may arise through another commonly used feature: declaring as part
of the project a set of directories containing all the sources obeying the
default naming scheme.
@@ -2755,24 +2759,22 @@ bodies:
used for VMS on the ia64
The dummy version :file:`s-asthan.adb` simply raises exceptions noting that
-this operating system feature is not available, and the two remaining
+this operating system feature is not available and the two remaining
versions interface with the corresponding versions of VMS to provide
VMS-compatible AST handling. The GNAT build script knows the architecture
and operating system, and automatically selects the right version,
renaming it if necessary to :file:`s-asthan.adb` before the run-time build.
-Another style for arranging alternative implementations is through Ada's
-access-to-subprogram facility.
-In case some functionality is to be conditionally included,
-you can declare an access-to-procedure variable ``Ref`` that is initialized
-to designate a 'do nothing' procedure, and then invoke ``Ref.all``
-when appropriate.
-In some library package, set ``Ref`` to ``Proc'Access`` for some
-procedure ``Proc`` that performs the relevant processing.
-The initialization only occurs if the library package is included in the
-program.
-The same idea can also be implemented using tagged types and dispatching
-calls.
+Another style for arranging alternative implementations is through
+Ada's access-to-subprogram facility. In case some functionality is to
+be conditionally included, you can declare an access-to-procedure
+variable ``Ref`` that is initialized to designate a 'do nothing'
+procedure, and then invoke ``Ref.all`` when appropriate. Then, in,
+some library package, set ``Ref`` to ``Proc'Access`` for some
+procedure ``Proc`` that performs the relevant processing. The
+initialization only occurs if the library package is included in the
+program. The same idea can also be implemented using tagged types and
+dispatching calls.
.. _Preprocessing:
@@ -2782,7 +2784,7 @@ Preprocessing
.. index:: Preprocessing
Although it is quite possible to conditionalize code without the use of
-C-style preprocessing, as described earlier in this section, it is
+C-style preprocessing, as described in the cases above, it is
nevertheless convenient in some cases to use the C approach. Moreover,
older Ada compilers have often provided some preprocessing capability,
so legacy code may depend on this approach, even though it is not
@@ -2794,9 +2796,9 @@ with legacy code on other compilers, to enable easier transition).
.. index:: gnatprep
-The preprocessor may be used in two separate modes. It can be used quite
-separately from the compiler, to generate a separate output source file
-that is then fed to the compiler as a separate step. This is the
+You can use the preprocessor used in two different modes. You can use it
+separately from the compiler to generate a separate output source file,
+which you then feed to the compiler as a separate step. This is the
``gnatprep`` utility, whose use is fully described in
:ref:`Preprocessing_with_gnatprep`.
@@ -2814,10 +2816,10 @@ The values of the symbols ``DEBUG`` and ``PRIORITY`` can be
defined either on the command line or in a separate file.
The other way of running the preprocessor is even closer to the C style and
-often more convenient. In this approach the preprocessing is integrated into
-the compilation process. The compiler is given the preprocessor input which
-includes ``#if`` lines etc, and then the compiler carries out the
-preprocessing internally and processes the resulting output.
+often more convenient. In this approach, the preprocessing is integrated into
+the compilation process. You pass the compiler the preprocessor input, which
+includes ``#if`` lines etc, and the compiler carries out the
+preprocessing internally and compiles the resulting output.
For more details on this approach, see :ref:`Integrated_Preprocessing`.
.. _Preprocessing_with_gnatprep:
@@ -2828,11 +2830,10 @@ Preprocessing with ``gnatprep``
.. index:: ! gnatprep
.. index:: Preprocessing (gnatprep)
-This section discusses how to use GNAT's ``gnatprep`` utility for simple
-preprocessing.
-Although designed for use with GNAT, ``gnatprep`` does not depend on any
-special GNAT features.
-For further discussion of conditional compilation in general, see
+This section discusses how to you can use GNAT's ``gnatprep`` utility
+for simple preprocessing. Although designed for use with GNAT,
+``gnatprep`` does not depend on any special GNAT features. For
+further discussion of conditional compilation in general, see
:ref:`Conditional_Compilation`.
.. _Preprocessing_Symbols:
@@ -2872,8 +2873,8 @@ where
* ``deffile``
is the full name of a text file containing definitions of
- preprocessing symbols to be referenced by the preprocessor. This argument is
- optional, and can be replaced by the use of the :switch:`-D` switch.
+ preprocessing symbols to be referenced by the preprocessor. You
+ can omit this argument and instead use the :switch:`-D` switch.
.. _Switches_for_gnatprep:
@@ -2884,12 +2885,12 @@ Switches for ``gnatprep``
.. index:: --version (gnatprep)
:switch:`--version`
- Display Copyright and version, then exit disregarding all other options.
+ Display copyright and version, then exit, disregarding all other options.
.. index:: --help (gnatprep)
:switch:`--help`
- If :switch:`--version` was not used, display usage and then exit disregarding
+ If :switch:`--version` was not used, display usage and then exit, disregarding
all other options.
.. index:: -b (gnatprep)
@@ -2904,44 +2905,44 @@ Switches for ``gnatprep``
:switch:`-c`
Causes both preprocessor lines and the lines deleted
by preprocessing to be retained in the output source as comments marked
- with the special string ``"--! "``. This option will result in line numbers
+ with the special string ``"--! "``. This option also results in line numbers
being preserved in the output file.
.. index:: -C (gnatprep)
:switch:`-C`
- Causes comments to be scanned. Normally comments are ignored by gnatprep.
- If this option is specified, then comments are scanned and any $symbol
- substitutions performed as in program text. This is particularly useful
- when structured comments are used (e.g., for programs written in a
- pre-2014 version of the SPARK Ada subset). Note that this switch is not
- available when doing integrated preprocessing (it would be useless in
- this context since comments are ignored by the compiler in any case).
+ Causes comments to be scanned. Normally comments are ignored by
+ ``gnatprep``. If you specify this option, ``gnatprep`` scans
+ comments and any $symbol substitutions performed as in program
+ text. You will find this particularly useful when structured
+ comments are used (e.g., for programs written in a pre-2014 version
+ of the SPARK Ada subset). This switch is not available
+ when doing integrated preprocessing (it would be useless in this
+ context since comments are always ignored by the compiler).
.. index:: -D (gnatprep)
:switch:`-D{symbol}[={value}]`
- Defines a new preprocessing symbol with the specified value. If no value is given
- on the command line, then symbol is considered to be ``True``. This switch
- can be used in place of a definition file.
+ Defines a new preprocessing symbol with the specified value. If you
+ don't specify a value, the symbol is defined to be ``True``. You can
+ use this switch instead of providing a definition file.
.. index:: -r (gnatprep)
:switch:`-r`
- Causes a ``Source_Reference`` pragma to be generated that
+ Causes ``gnatprep`` to generate a ``Source_Reference`` pragma that
references the original input file, so that error messages will use
the file name of this original file. The use of this switch implies
- that preprocessor lines are not to be removed from the file, so its
- use will force ``-b`` mode if ``-c``
- has not been specified explicitly.
+ that preprocessor lines are not to be removed from the file, so
+ the :switch:`-b` and :switch:`-c` are always enabled.
- Note that if the file to be preprocessed contains multiple units, then
- it will be necessary to ``gnatchop`` the output file from
+ If the file to be preprocessed contains multiple units, you
+ must call ``gnatchop`` on the the output file from
``gnatprep``. If a ``Source_Reference`` pragma is present
in the preprocessed file, it will be respected by
``gnatchop -r``
so that the final chopped files will correctly refer to the original
- input source file for ``gnatprep``.
+ input source file passed to ``gnatprep``.
.. index:: -s (gnatprep)
@@ -2958,20 +2959,20 @@ Switches for ``gnatprep``
.. index:: -u (gnatprep)
:switch:`-u`
- Causes undefined symbols to be treated as having the value FALSE in the context
- of a preprocessor test. In the absence of this option, an undefined symbol in
- a ``#if`` or ``#elsif`` test will be treated as an error.
+ Causes undefined symbols to be treated as having the value ``False``
+ in the context of a preprocessor test. If you don't specify this
+ switch, ``gnatprep`` will treat an undefined symbol in a ``#if`` or
+ ``#elsif`` test as an error.
.. index:: -v (gnatprep)
:switch:`-v`
- Verbose mode: generates more output about work done.
+ Verbose mode: generates more output about what is done.
-
-Note: if neither :switch:`-b` nor :switch:`-c` is present,
+Note: if you don't specify either :switch:`-b` or :switch:`-c`,
then preprocessor lines and
-deleted lines are completely removed from the output, unless -r is
-specified, in which case -b is assumed.
+deleted lines are completely removed from the output, unless you specify
+:switch:`-r`, in which case ``gnatprep`` enables the :switch:`-b` switch.
.. _Form_of_Definitions_File:
@@ -2989,9 +2990,9 @@ where ``symbol`` is a preprocessing symbol, and ``value`` is one of the followin
* A string literal using normal Ada syntax, or
* Any sequence of characters from the set {letters, digits, period, underline}.
-Comment lines may also appear in the definitions file, starting with
-the usual ``--``,
-and comments may be added to the definitions lines.
+You may also place comment lines in the definitions file, starting with
+the usual ``--``
+and comments may be added to the end of each definition line.
.. _Form_of_Input_Text_for_gnatprep:
@@ -2999,10 +3000,10 @@ and comments may be added to the definitions lines.
Form of Input Text for ``gnatprep``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-The input text may contain preprocessor conditional inclusion lines,
+The input text contains preprocessor conditional inclusion lines
as well as general symbol substitution sequences.
-The preprocessor conditional inclusion commands have the form:
+Preprocessor conditional inclusion commands have the form:
.. code-block:: c
@@ -3035,26 +3036,11 @@ In this example, <expression> is defined by the following grammar::
<expression> ::= <expression> or else <expression>
<expression> ::= ( <expression> )
-Note the following restriction: it is not allowed to have "and" or "or"
-following "not" in the same expression without parentheses. For example, this
-is not allowed:
-
-.. code-block:: ada
-
- not X or Y
-
-This can be expressed instead as one of the following forms:
-
-.. code-block:: ada
-
- (not X) or Y
- not (X or Y)
-
-For the first test (<expression> ::= <symbol>) the symbol must have
-either the value true or false, that is to say the right-hand of the
+For the first test, (<expression> ::= <symbol>), the symbol must have
+either the value true or false. The right-hand of the
symbol definition must be one of the (case-insensitive) literals
-``True`` or ``False``. If the value is true, then the
-corresponding lines are included, and if the value is false, they are
+``True`` or ``False``. If the value is true, the
+corresponding lines are included and if the value is false, they are
excluded.
When comparing a symbol to an integer, the integer is any non negative
@@ -3068,34 +3054,32 @@ switch on the command line. Otherwise, the test is false.
The equality tests are case insensitive, as are all the preprocessor lines.
-If the symbol referenced is not defined in the symbol definitions file,
-then the effect depends on whether or not switch :switch:`-u`
-is specified. If so, then the symbol is treated as if it had the value
-false and the test fails. If this switch is not specified, then
-it is an error to reference an undefined symbol. It is also an error to
-reference a symbol that is defined with a value other than ``True``
-or ``False``.
-
-The use of the ``not`` operator inverts the sense of this logical test.
-The ``not`` operator cannot be combined with the ``or`` or ``and``
-operators, without parentheses. For example, "if not X or Y then" is not
-allowed, but "if (not X) or Y then" and "if not (X or Y) then" are.
-
-The ``then`` keyword is optional as shown
-
-The ``#`` must be the first non-blank character on a line, but
-otherwise the format is free form. Spaces or tabs may appear between
-the ``#`` and the keyword. The keywords and the symbols are case
-insensitive as in normal Ada code. Comments may be used on a
-preprocessor line, but other than that, no other tokens may appear on a
-preprocessor line. Any number of ``elsif`` clauses can be present,
-including none at all. The ``else`` is optional, as in Ada.
-
-The ``#`` marking the start of a preprocessor line must be the first
-non-blank character on the line, i.e., it must be preceded only by
-spaces or horizontal tabs.
-
-Symbol substitution outside of preprocessor lines is obtained by using
+If the symbol referenced is not defined in the symbol definitions
+file, the result depends on whether or not you have specified the
+:switch:`-u` switch. If you have, the symbol is treated as if it had
+the value false and the test fails. If not,
+it's an error to reference an undefined symbol. It's also an
+error to reference a symbol that you have defined with a value other than
+``True`` or ``False``.
+
+The use of the ``not`` operator inverts the sense of this logical
+test. You can't combine the ``not`` operator with the ``or`` or
+``and`` operators without parentheses. For example, you can't write
+"if not X or Y then" allowed, but can write either "if (not X) or Y
+then" or "if not (X or Y) then".
+
+The ``then`` keyword is optional, as shown.
+
+You must place the ``#`` in the first non-blank character on a line,
+i.e., it must be preceded only by spaces or horizontal tabs, but
+otherwise the format is free form. You may place spaces or tabs
+between the ``#`` and the keyword. The keywords and the symbols are
+case insensitive, as in normal Ada code. You can write comments on a
+preprocessor line, but other than that, you can't place any other
+tokens on a preprocessor line. You can have any number of ``elsif``
+clauses, including none at all. The ``else`` is optional, as in Ada.
+
+You obtain symbol substitution outside of preprocessor lines by using
the sequence::
$symbol
@@ -3103,12 +3087,12 @@ the sequence::
anywhere within a source line, except in a comment or within a
string literal. The identifier
following the ``$`` must match one of the symbols defined in the symbol
-definition file, and the result is to substitute the value of the
+definition file and the resulting output substitutes the value of the
symbol in place of ``$symbol`` in the output file.
-Note that although the substitution of strings within a string literal
-is not possible, it is possible to have a symbol whose defined value is
-a string literal. So instead of setting XYZ to ``hello`` and writing:
+Note that although you can't substitute strings within a string
+literal, you can have a symbol whose defined value is a string
+literal. So instead of setting XYZ to ``hello`` and writing:
.. code-block:: ada
@@ -3129,12 +3113,12 @@ Integrated Preprocessing
------------------------
As noted above, a file to be preprocessed consists of Ada source code
-in which preprocessing lines have been inserted. However,
-instead of using ``gnatprep`` to explicitly preprocess a file as a separate
-step before compilation, you can carry out the preprocessing implicitly
-as part of compilation. Such *integrated preprocessing*, which is the common
-style with C, is performed when either or both of the following switches
-are passed to the compiler:
+in which preprocessing lines have been inserted. However, instead of
+using ``gnatprep`` to explicitly preprocess a file as a separate step
+before compilation, you can carry out the preprocessing implicitly as
+part of compilation. Such *integrated preprocessing*, which is the
+common style with C, is performed when you pass either or both of the
+following switches to the compiler:
* :switch:`-gnatep`, which specifies the *preprocessor data file*.
This file dictates how the source files will be preprocessed (e.g., which
@@ -3142,24 +3126,23 @@ are passed to the compiler:
* :switch:`-gnateD`, which defines values for preprocessing symbols.
-Integrated preprocessing applies only to Ada source files, it is
+Integrated preprocessing applies only to Ada source files; it's
not available for configuration pragma files.
-With integrated preprocessing, the output from the preprocessor is not,
-by default, written to any external file. Instead it is passed
-internally to the compiler. To preserve the result of
-preprocessing in a file, either run ``gnatprep``
-in standalone mode or else supply the :switch:`-gnateG` switch
-(described below) to the compiler.
+With integrated preprocessing, GNAT doesn't write the output from the
+preprocessor, by default, to any external file. Instead it's passed
+internally to the compiler. To preserve the result of preprocessing in
+a file, either run ``gnatprep`` in standalone mode or supply the
+:switch:`-gnateG` switch to the compiler.
When using project files:
- * the builder switch :switch:`-x` should be used if any Ada source is
- compiled with :switch:`gnatep=`, so that the compiler finds the
- *preprocessor data file*.
+ * you should use the builder switch :switch:`-x` if any Ada source is
+ compiled with :switch:`gnatep=` so that the compiler finds the
+ *preprocessor data file*.
- * the preprocessing data file and the symbol definition files should be
- located in the source directories of the project.
+ * you should place the preprocessing data file and the symbol
+ definition files in the source directories of the project.
Note that the ``gnatmake`` switch :switch:`-m` will almost
always trigger recompilation for sources that are preprocessed,
@@ -3196,7 +3179,7 @@ that relate to integrated preprocessing.
can optionally identify a *definition file* that assigns values to
preprocessor symbols, as well as a list of switches that relate to
preprocessing.
- Empty lines and comments (using Ada syntax) are also permitted, with no
+ You can also include empty lines and comments (using Ada syntax), with no
semantic effect.
Here's an example of a preprocessor data file:
@@ -3231,8 +3214,8 @@ that relate to integrated preprocessing.
<switch> := (See below for list)
- Thus each preprocessor control line starts with either a literal string or
- the character '*':
+ Thus, you start each preprocessor control line either a literal
+ string or the character '*':
* A literal string is the file name (without directory information) of the source
file that will be input to the preprocessor.
@@ -3242,17 +3225,18 @@ that relate to integrated preprocessing.
that are not specified explicitly on other lines (the order of the lines is not
significant).
- It is an error to have two lines with the same file name or two
- lines starting with the character '*'.
+ You cannot have two lines with the same file name or two
+ lines starting with the '*' character.
- After the file name or '*', an optional literal string specifies the name of
- the definition file to be used for preprocessing
- (:ref:`Form_of_Definitions_File`). The definition files are found by the
- compiler in one of the source directories. In some cases, when compiling
- a source in a directory other than the current directory, if the definition
- file is in the current directory, it may be necessary to add the current
- directory as a source directory through the :switch:`-I` switch; otherwise
- the compiler would not find the definition file.
+ After the file name or '*', you can place an optional literal string
+ to specify the name of the definition file to be used for
+ preprocessing (:ref:`Form_of_Definitions_File`). The definition
+ files are found by the compiler in one of the source directories. In
+ some cases, when compiling a source in a directory other than the
+ current directory, if the definition file is in the current
+ directory, you may need to add the current directory as a
+ source directory through the :switch:`-I` switch; otherwise the
+ compiler would not find the definition file.
Finally, switches similar to those of ``gnatprep`` may optionally appear:
@@ -3262,7 +3246,6 @@ that relate to integrated preprocessing.
This switch is always implied; however, if specified after :switch:`-c`
it cancels the effect of :switch:`-c`.
-
:switch:`-c`
Causes both preprocessor lines and the lines deleted
by preprocessing to be retained as comments marked
@@ -3271,12 +3254,12 @@ that relate to integrated preprocessing.
:switch:`-D{symbol}={new_value}`
Define or redefine ``symbol`` to have ``new_value`` as its value.
- The permitted form for ``symbol`` is either an Ada identifier, or any Ada reserved word
- aside from ``if``,
- ``else``, ``elsif``, ``end``, ``and``, ``or`` and ``then``.
- The permitted form for ``new_value`` is a literal string, an Ada identifier or any Ada reserved
- word. A symbol declared with this switch replaces a symbol with the
- same name defined in a definition file.
+ You can write ``symbol`` as either an Ada identifier or any Ada
+ reserved word aside from ``if``, ``else``, ``elsif``, ``end``,
+ ``and``, ``or`` and ``then``. You can write ``new_value`` as a
+ literal string, an Ada identifier or any Ada reserved word. A
+ symbol declared with this switch replaces a symbol with the same
+ name defined in a definition file.
:switch:`-s`
@@ -3285,23 +3268,24 @@ that relate to integrated preprocessing.
:switch:`-u`
- Causes undefined symbols to be treated as having the value ``FALSE``
- in the context
- of a preprocessor test. In the absence of this option, an undefined symbol in
- a ``#if`` or ``#elsif`` test will be treated as an error.
+ Causes undefined symbols to be treated as having the value
+ ``FALSE`` in the context of a preprocessor test. If you don't
+ specify this switch, an undefined symbol in a ``#if`` or
+ ``#elsif`` test is treated as an error.
.. index:: -gnateD (gcc)
:switch:`-gnateD{symbol}[={new_value}]`
- Define or redefine ``symbol`` to have ``new_value`` as its value. If no value
- is supplied, then the value of ``symbol`` is ``True``.
- The form of ``symbol`` is an identifier, following normal Ada (case-insensitive)
- rules for its syntax, and ``new_value`` is either an arbitrary string between double
- quotes or any sequence (including an empty sequence) of characters from the
- set (letters, digits, period, underline).
- Ada reserved words may be used as symbols, with the exceptions of ``if``,
- ``else``, ``elsif``, ``end``, ``and``, ``or`` and ``then``.
+ Define or redefine ``symbol`` to have ``new_value`` as its value. If
+ you don't specify a value, the value of ``symbol`` is ``True``. You
+ write ``symbol`` as an identifier, following normal Ada
+ (case-insensitive) rules for its syntax, and ``new_value`` as either
+ an arbitrary string between double quotes or any sequence (including
+ an empty sequence) of characters from the set (letters, digits,
+ period, underline). Ada reserved words may be used as symbols, with
+ the exceptions of ``if``, ``else``, ``elsif``, ``end``, ``and``,
+ ``or`` and ``then``.
Examples:
@@ -3323,7 +3307,7 @@ that relate to integrated preprocessing.
create or overwrite :file:`filename.extension.prep` to contain
the result of the preprocessing.
For example if the source file is :file:`foo.adb` then
- the output file will be :file:`foo.adb.prep`.
+ the output file is :file:`foo.adb.prep`.
.. _Mixed_Language_Programming:
@@ -3343,14 +3327,14 @@ Interfacing to C
Interfacing Ada with a foreign language such as C involves using
compiler directives to import and/or export entity definitions in each
-language -- using ``extern`` statements in C, for instance, and the
+language -- using ``extern`` statements in C, for example, and the
``Import``, ``Export``, and ``Convention`` pragmas in Ada.
A full treatment of these topics is provided in Appendix B, section 1
of the Ada Reference Manual.
There are two ways to build a program using GNAT that contains some Ada
sources and some foreign language sources, depending on whether or not
-the main subprogram is written in Ada. Here is a source example with
+the main subprogram is written in Ada. Here's an example with
the main subprogram in Ada:
.. code-block:: c
@@ -3409,7 +3393,7 @@ To build this example:
$ gcc -c file1.c
$ gcc -c file2.c
-* Then, compile the Ada units to produce a set of object files and ALI
+* Then compile the Ada units to produce a set of object files and ALI
files:
.. code-block:: sh
@@ -3422,14 +3406,14 @@ To build this example:
$ gnatbind my_main.ali
-* Link the Ada main program, the Ada objects and the other language
+* Link the Ada main program, the Ada objects, and the other language
objects:
.. code-block:: sh
$ gnatlink my_main.ali file1.o file2.o
-The last three steps can be grouped in a single command:
+You can merge the last three steps into a single command:
.. code-block:: sh
@@ -3438,18 +3422,19 @@ The last three steps can be grouped in a single command:
.. index:: Binder output file
-If the main program is in a language other than Ada, then you may have
-more than one entry point into the Ada subsystem. You must use a special
+If the main program is in a language other than Ada, you may have more
+than one entry point into the Ada subsystem. You must use a special
binder option to generate callable routines that initialize and
finalize the Ada units (:ref:`Binding_with_Non-Ada_Main_Programs`).
-Calls to the initialization and finalization routines must be inserted
-in the main program, or some other appropriate point in the code. The
-call to initialize the Ada units must occur before the first Ada
-subprogram is called, and the call to finalize the Ada units must occur
-after the last Ada subprogram returns. The binder will place the
-initialization and finalization subprograms into the
-:file:`b~xxx.adb` file where they can be accessed by your C
-sources. To illustrate, we have the following example:
+You must insert calls to the initialization and finalization routines
+in the main program or some other appropriate point in the code. You
+must place the call to initialize the Ada units so that it occurs
+before the first Ada subprogram is called and must place the call to
+finalize the Ada units so it occurs after the last Ada subprogram
+returns. The binder places the initialization and finalization
+subprograms into the :file:`b~xxx.adb` file, where they can be
+accessed by your C sources. To illustrate, we have the following
+example:
.. code-block:: c
@@ -3558,7 +3543,7 @@ Calling Conventions
.. index:: Calling Conventions
-GNAT follows standard calling sequence conventions and will thus interface
+GNAT follows standard calling sequence conventions and will interface
to any other language that also follows these conventions. The following
Convention identifiers are recognized by GNAT:
@@ -3570,33 +3555,25 @@ Convention identifiers are recognized by GNAT:
.. index:: Convention Ada
``Ada``
- This indicates that the standard Ada calling sequence will be
+ This indicates that the standard Ada calling sequence is
used and all Ada data items may be passed without any limitations in the
- case where GNAT is used to generate both the caller and callee. It is also
- possible to mix GNAT generated code and code generated by another Ada
- compiler. In this case, the data types should be restricted to simple
+ case where GNAT is used to generate both the caller and callee. You can also
+ mix GNAT generated code and code generated by another Ada
+ compiler. In this case, you should restrict the data types to simple
cases, including primitive types. Whether complex data types can be passed
- depends on the situation. Probably it is safe to pass simple arrays, such
+ depends on the situation. It is probably safe to pass simple arrays, such
as arrays of integers or floats. Records may or may not work, depending
on whether both compilers lay them out identically. Complex structures
involving variant records, access parameters, tasks, or protected types,
are unlikely to be able to be passed.
- Note that in the case of GNAT running
- on a platform that supports HP Ada 83, a higher degree of compatibility
- can be guaranteed, and in particular records are laid out in an identical
- manner in the two compilers. Note also that if output from two different
- compilers is mixed, the program is responsible for dealing with elaboration
- issues. Probably the safest approach is to write the main program in the
- version of Ada other than GNAT, so that it takes care of its own elaboration
- requirements, and then call the GNAT-generated adainit procedure to ensure
- elaboration of the GNAT components. Consult the documentation of the other
- Ada compiler for further details on elaboration.
-
- However, it is not possible to mix the tasking run time of GNAT and
- HP Ada 83, all the tasking operations must either be entirely within
- GNAT compiled sections of the program, or entirely within HP Ada 83
- compiled sections of the program.
+ If output from two different compilers is mixed, you are responsible
+ for dealing with elaboration issues. Probably the safest approach is
+ to write the main program in the version of Ada other than GNAT, so
+ it takes care of its own elaboration requirements, and
+ call the GNAT-generated adainit procedure to ensure elaboration of
+ the GNAT components. Consult the documentation of the other Ada
+ compiler for further details on elaboration.
.. index:: Interfacing to Assembly
@@ -3622,7 +3599,7 @@ Convention identifiers are recognized by GNAT:
.. index:: COBOL
``COBOL``
- Data will be passed according to the conventions described
+ Data is passed according to the conventions described
in section B.4 of the Ada Reference Manual.
.. index:: C
@@ -3632,7 +3609,7 @@ Convention identifiers are recognized by GNAT:
``C``
- Data will be passed according to the conventions described
+ Data is passed according to the conventions described
in section B.3 of the Ada Reference Manual.
A note on interfacing to a C 'varargs' function:
@@ -3643,7 +3620,7 @@ Convention identifiers are recognized by GNAT:
In C, ``varargs`` allows a function to take a variable number of
arguments. There is no direct equivalent in this to Ada. One
- approach that can be used is to create a C wrapper for each
+ approach that you can use is to create a C wrapper for each
different profile and then interface to this C wrapper. For
example, to print an ``int`` value using ``printf``,
create a C function ``printfi`` that takes two arguments, a
@@ -3654,8 +3631,8 @@ Convention identifiers are recognized by GNAT:
It may work on some platforms to directly interface to
a ``varargs`` function by providing a specific Ada profile
for a particular call. However, this does not work on
- all platforms, since there is no guarantee that the
- calling sequence for a two argument normal C function
+ all platforms since there is no guarantee that the
+ calling sequence for a two-argument normal C function
is the same as for calling a ``varargs`` C function with
the same two arguments.
@@ -3680,7 +3657,7 @@ Convention identifiers are recognized by GNAT:
``C_Plus_Plus`` (or ``CPP``)
- This stands for C++. For most purposes this is identical to C.
+ This stands for C++. For most purposes, this is identical to C.
See the separate description of the specialized GNAT pragmas relating to
C++ interfacing for further details.
@@ -3690,24 +3667,24 @@ Convention identifiers are recognized by GNAT:
``Fortran``
- Data will be passed according to the conventions described
+ Data is passed according to the conventions described
in section B.5 of the Ada Reference Manual.
``Intrinsic``
This applies to an intrinsic operation, as defined in the Ada
Reference Manual. If a pragma Import (Intrinsic) applies to a subprogram,
- this means that the body of the subprogram is provided by the compiler itself,
- usually by means of an efficient code sequence, and that the user does not
+ it means the body of the subprogram is provided by the compiler itself,
+ usually by means of an efficient code sequence, and that you don't
supply an explicit body for it. In an application program, the pragma may
be applied to the following sets of names:
- * Rotate_Left, Rotate_Right, Shift_Left, Shift_Right, Shift_Right_Arithmetic.
+ * ``Rotate_Left``, ``Rotate_Right``, ``Shift_Left``, ``Shift_Right``, ``Shift_Right_Arithmetic``.
The corresponding subprogram declaration must have
two formal parameters. The
- first one must be a signed integer type or a modular type with a binary
- modulus, and the second parameter must be of type Natural.
+ first must be a signed integer type or a modular type with a binary
+ modulus and the second parameter must be of type Natural.
The return type must be the same as the type of the first argument. The size
of this type can only be 8, 16, 32, or 64.
@@ -3728,9 +3705,9 @@ Convention identifiers are recognized by GNAT:
return Velocity;
pragma Import (Intrinsic, "/");
- This common idiom is often programmed with a generic definition and an
+ You often program this common idiom with a generic definition and an
explicit body. The pragma makes it simpler to introduce such declarations.
- It incurs no overhead in compilation time or code size, because it is
+ It incurs no overhead in compilation time or code size because it is
implemented as a single machine instruction.
@@ -3738,7 +3715,7 @@ Convention identifiers are recognized by GNAT:
declaration to
a compiler builtin by name with back-ends where such interfaces are
available. A typical example is the set of ``__builtin`` functions
- exposed by the GCC back-end, as in the following example:
+ exposed by the ``gcc`` back-end, as in the following example:
.. code-block:: ada
@@ -3746,7 +3723,7 @@ Convention identifiers are recognized by GNAT:
function builtin_sqrt (F : Float) return Float;
pragma Import (Intrinsic, builtin_sqrt, "__builtin_sqrtf");
- Most of the GCC builtins are accessible this way, and as for other
+ Most of the ``gcc`` builtins are accessible this way, and as for other
import conventions (e.g. C), it is the user's responsibility to ensure
that the Ada subprogram profile matches the underlying builtin
expectations.
@@ -3755,10 +3732,10 @@ Convention identifiers are recognized by GNAT:
.. index:: Convention Stdcall
``Stdcall``
- This is relevant only to Windows implementations of GNAT,
- and specifies that the ``Stdcall`` calling sequence will be used,
- as defined by the NT API. Nevertheless, to ease building
- cross-platform bindings this convention will be handled as a ``C`` calling
+ This is relevant only to Windows implementations of GNAT
+ and specifies that the ``Stdcall`` calling sequence is used,
+ as defined by the NT API. To simplify building
+ cross-platform bindings, this convention is handled as a ``C`` calling
convention on non-Windows platforms.
.. index:: DLL
@@ -3784,8 +3761,8 @@ Convention identifiers are recognized by GNAT:
should provide a stub body that raises ``Program_Error``.
GNAT additionally provides a useful pragma ``Convention_Identifier``
-that can be used to parameterize conventions and allow additional synonyms
-to be specified. For example if you have legacy code in which the convention
+that you can use to parameterize conventions and allow additional synonyms.
+For example, if you have legacy code in which the convention
identifier Fortran77 was used for Fortran, you can use the configuration
pragma:
@@ -3793,9 +3770,9 @@ pragma:
pragma Convention_Identifier (Fortran77, Fortran);
-And from now on the identifier Fortran77 may be used as a convention
+And from now on, you can use the identifier ``Fortran77`` as a convention
identifier (for example in an ``Import`` pragma) with the same
-meaning as Fortran.
+meaning as ``Fortran``.
.. _Building_Mixed_Ada_and_C++_Programs:
@@ -3803,7 +3780,7 @@ meaning as Fortran.
Building Mixed Ada and C++ Programs
-----------------------------------
-A programmer inexperienced with mixed-language development may find that
+If you are inexperienced with mixed-language development, you may find that
building an application containing both Ada and C++ code can be a
challenge. This section gives a few hints that should make this task easier.
@@ -3816,20 +3793,21 @@ GNAT supports interfacing with the G++ compiler (or any C++ compiler
generating code that is compatible with the G++ Application Binary
Interface ---see http://itanium-cxx-abi.github.io/cxx-abi/abi.html).
-Interfacing can be done at 3 levels: simple data, subprograms, and
+You can do interfacing at three levels: simple data, subprograms, and
classes. In the first two cases, GNAT offers a specific ``Convention C_Plus_Plus``
(or ``CPP``) that behaves exactly like ``Convention C``.
Usually, C++ mangles the names of subprograms. To generate proper mangled
names automatically, see :ref:`Generating_Ada_Bindings_for_C_and_C++_headers`).
-This problem can also be addressed manually in two ways:
+You can also address this problem addressed manually in two ways:
* by modifying the C++ code in order to force a C convention using
the ``extern "C"`` syntax.
-* by figuring out the mangled name (using e.g. ``nm``) and using it as the
- Link_Name argument of the pragma import.
+* by figuring out the mangled name (using e.g. ``nm`` or by looking at the
+ assembly code generated by the C++ compiler) and using it as the
+ ``Link_Name`` argument of the pragma ``Import``.
-Interfacing at the class level can be achieved by using the GNAT specific
+You can achieve interfacing at the class level by using the GNAT specific
pragmas such as ``CPP_Constructor``. See the :title:`GNAT_Reference_Manual` for additional information.
.. _Linking_a_Mixed_C++_and_Ada_Program:
@@ -3837,22 +3815,21 @@ pragmas such as ``CPP_Constructor``. See the :title:`GNAT_Reference_Manual` for
Linking a Mixed C++ & Ada Program
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Usually the linker of the C++ development system must be used to link
-mixed applications because most C++ systems will resolve elaboration
+Usually the linker, of the C++ development system must be used to link
+mixed applications because most C++ systems resolve elaboration
issues (such as calling constructors on global class instances)
transparently during the link phase. GNAT has been adapted to ease the
-use of a foreign linker for the last phase. Three cases can be
-considered:
+use of a foreign linker for the last phase. We consider three cases:
* Using GNAT and G++ (GNU C++ compiler) from the same GCC installation:
- The C++ linker can simply be called by using the C++ specific driver
+ You can call the C++ linker by using the C++ specific driver
called ``g++``.
- Note that if the C++ code uses inline functions, you will need to
- compile your C++ code with the :switch:`-fkeep-inline-functions` switch in
- order to provide an existing function implementation that the Ada code can
- link with.
+ If the C++ code uses inline functions that you plan to call from
+ Ada, you need to compile your C++ code with the
+ :switch:`-fkeep-inline-functions` so ``g++`` doesn't delete these
+ functions.
.. code-block:: sh
@@ -3862,28 +3839,28 @@ considered:
* Using GNAT and G++ from two different GCC installations: If both
- compilers are on the :envvar:`PATH`, the previous method may be used. It is
- important to note that environment variables such as
+ compilers are on the :envvar:`PATH`, you may use the previous
+ method. However, environment variables such as
:envvar:`C_INCLUDE_PATH`, :envvar:`GCC_EXEC_PREFIX`,
- :envvar:`BINUTILS_ROOT`, and
- :envvar:`GCC_ROOT` will affect both compilers
- at the same time and may make one of the two compilers operate
- improperly if set during invocation of the wrong compiler. It is also
- very important that the linker uses the proper :file:`libgcc.a` GCC
- library -- that is, the one from the C++ compiler installation. The
- implicit link command as suggested in the ``gnatmake`` command
- from the former example can be replaced by an explicit link command with
- the full-verbosity option in order to verify which library is used:
+ :envvar:`BINUTILS_ROOT`, and :envvar:`GCC_ROOT` affect both
+ compilers at the same time and may make one of the two compilers
+ operate improperly if set during invocation of the wrong compiler.
+ It is also very important that the linker uses the proper
+ :file:`libgcc.a` ``gcc`` library -- that is, the one from the C++
+ compiler installation. You can replace the implicit link command as
+ suggested in the ``gnatmake`` command from the former example with
+ an explicit link command with the full-verbosity option
+ in order to verify which library is used:
.. code-block:: sh
$ gnatbind ada_unit
$ gnatlink -v -v ada_unit file1.o file2.o --LINK=c++
- If there is a problem due to interfering environment variables, it can
- be worked around by using an intermediate script. The following example
+ If there's a problem due to interfering environment variables, you can
+ work around it by using an intermediate script. The following example
shows the proper script to use when GNAT has not been installed at its
- default location and g++ has been installed at its default location:
+ default location and ``g++`` has been installed at its default location:
.. code-block:: sh
@@ -3895,13 +3872,13 @@ considered:
$ gnatlink -v -v ada_unit file1.o file2.o --LINK=./my_script
-* Using a non-GNU C++ compiler: The commands previously described can be
+* Using a non-GNU C++ compiler: You can use the commands previously described
used to insure that the C++ linker is used. Nonetheless, you need to add
a few more parameters to the link command line, depending on the exception
mechanism used.
- If the ``setjmp`` / ``longjmp`` exception mechanism is used, only the paths
- to the ``libgcc`` libraries are required:
+ If you are using the ``setjmp`` / ``longjmp`` exception mechanism, you need only
+ inclue the paths to the ``libgcc`` libraries:
.. code-block:: sh
@@ -3913,9 +3890,9 @@ considered:
where CC is the name of the non-GNU C++ compiler.
- If the "zero cost" exception mechanism is used, and the platform
+ If you are using the "zero cost" exception mechanism and the platform
supports automatic registration of exception tables (e.g., Solaris),
- paths to more objects are required:
+ you need to include paths to more objects:
.. code-block:: sh
@@ -3927,10 +3904,10 @@ considered:
$ gnatlink ada_unit file1.o file2.o --LINK=./my_script
- If the "zero cost exception" mechanism is used, and the platform
+ If you are using the "zero cost exception" mechanism is used and the platform
doesn't support automatic registration of exception tables (e.g., HP-UX
- or AIX), the simple approach described above will not work and
- a pre-linking phase using GNAT will be necessary.
+ or AIX), the simple approach described above won't work and
+ a you will need to preform a pre-linking phase using GNAT.
Another alternative is to use the :command:`gprbuild` multi-language builder
@@ -3944,12 +3921,12 @@ A Simple Example
The following example, provided as part of the GNAT examples, shows how
to achieve procedural interfacing between Ada and C++ in both
-directions. The C++ class A has two methods. The first method is exported
+directions. The C++ class ``A`` has two methods. The first method is exported
to Ada by the means of an extern C wrapper function. The second method
calls an Ada subprogram. On the Ada side, the C++ calls are modelled by
a limited record with a layout comparable to the C++ class. The Ada
subprogram, in turn, calls the C++ method. So, starting from the C++
-main program, the process passes back and forth between the two
+main program, execution passes back and forth between the two
languages.
Here are the compilation commands:
@@ -4072,13 +4049,13 @@ Here are the corresponding sources:
Interfacing with C++ constructors
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-In order to interface with C++ constructors GNAT provides the
+To interface with C++ constructors GNAT provides the
``pragma CPP_Constructor`` (see the :title:`GNAT_Reference_Manual`
for additional information).
-In this section we present some common uses of C++ constructors
+In this section, we present some common uses of C++ constructors
in mixed-languages programs in GNAT.
-Let us assume that we need to interface with the following
+Let us assume we need to interface with the following
C++ class:
.. code-block:: cpp
@@ -4093,7 +4070,7 @@ C++ class:
Root(int v, int w); // 2nd non-default constructor
};
-For this purpose we can write the following package spec (further
+For this purpose, we can write the following package spec (further
information on how to build this spec is available in
:ref:`Interfacing_with_C++_at_the_Class_Level` and
:ref:`Generating_Ada_Bindings_for_C_and_C++_headers`).
@@ -4121,26 +4098,26 @@ information on how to build this spec is available in
pragma Cpp_Constructor (Constructor, "_ZN4RootC1Eii");
end Pkg_Root;
-On the Ada side the constructor is represented by a function (whose
+On the Ada side, the constructor is represented by a function (whose
name is arbitrary) that returns the classwide type corresponding to
the imported C++ class. Although the constructor is described as a
-function, it is typically a procedure with an extra implicit argument
+function, it's typically a procedure with an extra implicit argument
(the object being initialized) at the implementation level. GNAT
issues the appropriate call, whatever it is, to get the object
properly initialized.
Constructors can only appear in the following contexts:
-* On the right side of an initialization of an object of type ``T``.
-* On the right side of an initialization of a record component of type ``T``.
+* On the right side of an initialization of an object of type.
+* On the right side of an initialization of a record component of type.
* In an Ada 2005 limited aggregate.
* In an Ada 2005 nested limited aggregate.
* In an Ada 2005 limited aggregate that initializes an object built in
place by an extended return statement.
In a declaration of an object whose type is a class imported from C++,
-either the default C++ constructor is implicitly called by GNAT, or
-else the required C++ constructor must be explicitly called in the
+either the default C++ constructor is implicitly called by GNAT or you must
+explicitly call the required C++ constructor in the
expression that initializes the object. For example:
.. code-block:: ada
@@ -4152,12 +4129,12 @@ expression that initializes the object. For example:
The first two declarations are equivalent: in both cases the default C++
constructor is invoked (in the former case the call to the constructor is
-implicit, and in the latter case the call is explicit in the object
+implicit and in the latter case the call is explicit in the object
declaration). ``Obj3`` is initialized by the C++ non-default constructor
-that takes an integer argument, and ``Obj4`` is initialized by the
+that takes an integer argument and ``Obj4`` is initialized by the
non-default C++ constructor that takes two integers.
-Let us derive the imported C++ class in the Ada side. For example:
+Let's derive the imported C++ class in the Ada side. For example:
.. code-block:: ada
@@ -4165,8 +4142,8 @@ Let us derive the imported C++ class in the Ada side. For example:
C_Value : Natural := 2009;
end record;
-In this case the components DT inherited from the C++ side must be
-initialized by a C++ constructor, and the additional Ada components
+In this case, you must initialize the components ``DT`` inherited from
+the C++ side by a C++ constructor and the additional Ada components
of type DT are initialized by GNAT. The initialization of such an
object is done either by default, or by means of a function returning
an aggregate of type DT, or by means of an extension aggregate.
@@ -4179,14 +4156,14 @@ an aggregate of type DT, or by means of an extension aggregate.
The declaration of ``Obj5`` invokes the default constructors: the
C++ default constructor of the parent type takes care of the initialization
-of the components inherited from Root, and GNAT takes care of the default
+of the components inherited from Root and GNAT takes care of the default
initialization of the additional Ada components of type DT (that is,
``C_Value`` is initialized to value 2009). The order of invocation of
the constructors is consistent with the order of elaboration required by
Ada and C++. That is, the constructor of the parent type is always called
before the constructor of the derived type.
-Let us now consider a record that has components whose type is imported
+Let's now consider a record that has components whose type is imported
from C++. For example:
.. code-block:: ada
@@ -4201,15 +4178,14 @@ from C++. For example:
Data2 : Root := Constructor (D, 30);
end record;
-The initialization of an object of type ``Rec2`` will call the
-non-default C++ constructors specified for the imported components.
-For example:
+The initialization of an object of type ``Rec2`` calls the non-default
+C++ constructors specified for the imported components. For example:
.. code-block:: ada
Obj8 : Rec2 (40);
-Using Ada 2005 we can use limited aggregates to initialize an object
+Using Ada 2005, we can use limited aggregates to initialize an object
invoking C++ constructors that differ from those specified in the type
declarations. For example:
@@ -4220,17 +4196,17 @@ declarations. For example:
others => <>);
The above declaration uses an Ada 2005 limited aggregate to
-initialize ``Obj9``, and the C++ constructor that has two integer
+initialize ``Obj9`` and the C++ constructor that has two integer
arguments is invoked to initialize the ``Data1`` component instead
of the constructor specified in the declaration of type ``Rec1``. In
-Ada 2005 the box in the aggregate indicates that unspecified components
+Ada 2005, the box in the aggregate indicates that unspecified components
are initialized using the expression (if any) available in the component
declaration. That is, in this case discriminant ``D`` is initialized
to value ``20``, ``Value`` is initialized to value 1000, and the
non-default C++ constructor that handles two integers takes care of
initializing component ``Data2`` with values ``20,30``.
-In Ada 2005 we can use the extended return statement to build the Ada
+In Ada 2005, we can use the extended return statement to build the Ada
equivalent to C++ non-default constructors. For example:
.. code-block:: ada
@@ -4246,26 +4222,26 @@ equivalent to C++ non-default constructors. For example:
end record;
end Constructor;
-In this example the extended return statement construct is used to
-build in place the returned object whose components are initialized
-by means of a limited aggregate. Any further action associated with
-the constructor can be placed inside the construct.
+In this example, we use the extended return statement construct to
+build in place the returned object whose components are initialized by
+means of a limited aggregate. We could also place any further action
+associated with the constructor inside the construct.
.. _Interfacing_with_C++_at_the_Class_Level:
Interfacing with C++ at the Class Level
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-In this section we demonstrate the GNAT features for interfacing with
+In this section, we demonstrate the GNAT features for interfacing with
C++ by means of an example making use of Ada 2005 abstract interface
types. This example consists of a classification of animals; classes
-have been used to model our main classification of animals, and
+have been used to model our main classification of animals and
interfaces provide support for the management of secondary
classifications. We first demonstrate a case in which the types and
constructors are defined on the C++ side and imported from the Ada
-side, and latter the reverse case.
+side and then the reverse case.
-The root of our derivation will be the ``Animal`` class, with a
+The root of our derivation is the ``Animal`` class, with a
single private attribute (the ``Age`` of the animal), a constructor,
and two public primitives to set and get the value of this attribute.
@@ -4281,7 +4257,7 @@ and two public primitives to set and get the value of this attribute.
};
Abstract interface types are defined in C++ by means of classes with pure
-virtual functions and no data members. In our example we will use two
+virtual functions and no data members. In our example we use two
interfaces that provide support for the common management of ``Carnivore``
and ``Domestic`` animals:
@@ -4313,7 +4289,7 @@ both Carnivore and Domestic, that is:
char *Owner;
};
-In the following examples we will assume that the previous declarations are
+In the following examples we assume that the previous declarations are
located in a file named :file:`animals.h`. The following package demonstrates
how to import these C++ declarations from the Ada side:
@@ -4364,33 +4340,35 @@ how to import these C++ declarations from the Ada side:
pragma Import (CPP, New_Dog, "_ZN3DogC2Ev");
end Animals;
-Thanks to the compatibility between GNAT run-time structures and the C++ ABI,
-interfacing with these C++ classes is easy. The only requirement is that all
-the primitives and components must be declared exactly in the same order in
-the two languages.
-
-Regarding the abstract interfaces, we must indicate to the GNAT compiler by
-means of a ``pragma Convention (C_Plus_Plus)``, the convention used to pass
-the arguments to the called primitives will be the same as for C++. For the
-imported classes we use ``pragma Import`` with convention ``C_Plus_Plus``
-to indicate that they have been defined on the C++ side; this is required
-because the dispatch table associated with these tagged types will be built
-in the C++ side and therefore will not contain the predefined Ada primitives
-which Ada would otherwise expect.
-
-As the reader can see there is no need to indicate the C++ mangled names
+Thanks to the compatibility between GNAT run-time structures and the
+C++ ABI, interfacing with these C++ classes is easy. The only
+requirement is that you must declare all the primitives and components
+exactly in the same order in the two languages.
+
+Regarding the abstract interfaces, we must indicate to the GNAT
+compiler, by means of a ``pragma Convention (C_Plus_Plus)``, that the
+convention used to pass the arguments to the called primitives will be
+the same as for C++. For the imported classes, we use ``pragma
+Import`` with convention ``C_Plus_Plus`` to indicate they have been
+defined on the C++ side; this is required because the dispatch table
+associated with these tagged types will be built in the C++ side and
+therefore will not contain the predefined Ada primitives which Ada
+would otherwise expect.
+
+As the reader can see, there is no need to indicate the C++ mangled names
associated with each subprogram because it is assumed that all the calls to
these primitives will be dispatching calls. The only exception is the
-constructor, which must be registered with the compiler by means of
-``pragma CPP_Constructor`` and needs to provide its associated C++
+constructor, which we must register with the compiler by means of
+``pragma CPP_Constructor`` and we need to provide its associated C++
mangled name because the Ada compiler generates direct calls to it.
-With the above packages we can now declare objects of type Dog on the Ada side
-and dispatch calls to the corresponding subprograms on the C++ side. We can
-also extend the tagged type Dog with further fields and primitives, and
-override some of its C++ primitives on the Ada side. For example, here we have
-a type derivation defined on the Ada side that inherits all the dispatching
-primitives of the ancestor from the C++ side.
+With the above packages, we can now declare objects of type ``Dog`` on
+the Ada side and dispatch calls to the corresponding subprograms on
+the C++ side. We can also extend the tagged type ``Dog`` with further
+fields and primitives and override some of its C++ primitives on the
+Ada side. For example, here we have a type derivation defined on the
+Ada side that inherits all the dispatching primitives of the ancestor
+from the C++ side.
.. code-block:: ada
@@ -4400,11 +4378,11 @@ primitives of the ancestor from the C++ side.
function Vaccination_Expired (A : Vaccinated_Dog) return Boolean;
end Vaccinated_Animals;
-It is important to note that, because of the ABI compatibility, the programmer
-does not need to add any further information to indicate either the object
+It is important to note that, because of the ABI compatibility, we
+don't need to add any further information to indicate either the object
layout or the dispatch table entry associated with each dispatching operation.
-Now let us define all the types and constructors on the Ada side and export
+Now let's define all the types and constructors on the Ada side and export
them to C++, using the same hierarchy of our previous example:
.. code-block:: ada
@@ -4454,7 +4432,7 @@ them to C++, using the same hierarchy of our previous example:
end Animals;
Compared with our previous example the only differences are the use of
-``pragma Convention`` (instead of ``pragma Import``), and the use of
+``pragma Convention`` (instead of ``pragma Import``) and the use of
``pragma Export`` to indicate to the GNAT compiler that the primitives will
be available to C++. Thanks to the ABI compatibility, on the C++ side there is
nothing else to be done; as explained above, the only requirement is that all
@@ -4502,23 +4480,22 @@ finalizing the Ada run-time system along the way:
Partition-Wide Settings
-----------------------
-When building a mixed-language application it is important to be aware that
+When building a mixed-language application, you must be aware that
Ada enforces some partition-wide settings that may implicitly impact the
behavior of the other languages.
-This is the case of certain signals that are reserved to the
+This is the case for certain signals that are reserved to the
implementation to implement proper Ada semantics (such as the behavior
of ``abort`` statements).
-
It means that the Ada part of the application may override signal handlers
that were previously installed by either the system or by other user code.
-If your application requires that either system or user signals be preserved
-then you need to instruct the Ada part not to install its own signal handler.
-This is done using ``pragma Interrupt_State`` that provides a general
+If your application requires that either system or user signals be preserved,
+you need to instruct the Ada part not to install its own signal handler.
+You do this using ``pragma Interrupt_State`` that provides a general
mechanism for overriding such uses of interrupts.
-Additionally, ``pragma Interrupts_System_By_Default`` can be used to default
+Additionally, you can use pragma ``Interrupts_System_By_Default`` to default
all interrupts to System.
The set of interrupts for which the Ada run-time library sets a specific signal
@@ -4530,9 +4507,9 @@ handler is the following:
* Ada.Interrupts.Names.SIGILL
* Ada.Interrupts.Names.SIGABRT
-The run-time library can be instructed not to install its signal handler for a
-particular signal by using the configuration pragma ``Interrupt_State`` in the
-Ada code. For example:
+You can instruct the run-time library not to install its signal
+handler for a particular signal by using the configuration pragma
+``Interrupt_State`` in the Ada code. For example:
.. code-block:: ada
@@ -4556,13 +4533,13 @@ Generating Ada Bindings for C and C++ headers
.. index:: C headers (binding generation)
.. index:: C++ headers (binding generation)
-GNAT includes a binding generator for C and C++ headers which is
+GNAT includes a binding generator for C and C++ headers, which is
intended to do 95% of the tedious work of generating Ada specs from C
or C++ header files.
-Note that this capability is not intended to generate 100% correct Ada specs,
-and will is some cases require manual adjustments, although it can often
-be used out of the box in practice.
+This capability is not intended to generate 100% correct Ada specs and
+it will in some cases require you to make manual adjustments, although
+it can often be used out of the box in practice.
Some of the known limitations include:
@@ -4570,12 +4547,12 @@ Some of the known limitations include:
constants. Function macros (macros with arguments) are partially translated
as comments, to be completed manually if needed.
* some extensions (e.g. vector types) are not supported
-* pointers to pointers are mapped to System.Address
-* identifiers with identical name (except casing) may generate compilation
- errors (e.g. ``shm_get`` vs ``SHM_GET``).
+* pointers to pointers are mapped to ``System.Address``
+* identifiers with names that are identical except for casing may generate
+ compilation errors (e.g. ``shm_get`` vs ``SHM_GET``).
The code is generated using Ada 2012 syntax, which makes it easier to interface
-with other languages. In most cases you can still use the generated binding
+with other languages. In most cases, you can still use the generated binding
even if your code is compiled using earlier versions of Ada (e.g. ``-gnat95``).
.. _Running_the_binding_generator:
@@ -4583,9 +4560,9 @@ even if your code is compiled using earlier versions of Ada (e.g. ``-gnat95``).
Running the Binding Generator
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-The binding generator is part of the ``gcc`` compiler and can be
-invoked via the :switch:`-fdump-ada-spec` switch, which will generate Ada
-spec files for the header files specified on the command line, and all
+The binding generator is part of the ``gcc`` compiler and you can
+invoke it via the :switch:`-fdump-ada-spec` switch, which generates Ada
+spec files for the header files specified on the command line and all
header files needed by these files transitively. For example:
.. code-block:: sh
@@ -4593,17 +4570,17 @@ header files needed by these files transitively. For example:
$ gcc -c -fdump-ada-spec -C /usr/include/time.h
$ gcc -c *.ads
-will generate, under GNU/Linux, the following files: :file:`time_h.ads`,
+generates, under GNU/Linux, the following files: :file:`time_h.ads`,
:file:`bits_time_h.ads`, :file:`stddef_h.ads`, :file:`bits_types_h.ads` which
-correspond to the files :file:`/usr/include/time.h`,
-:file:`/usr/include/bits/time.h`, etc..., and then compile these Ada specs.
-That is to say, the name of the Ada specs is in keeping with the relative path
+correspond to the files :file:`/usr/include/time.h`, and
+:file:`/usr/include/bits/time.h` and then compile these Ada specs.
+The name of the Ada specs is consistent with the relative path
under :file:`/usr/include/` of the header files. This behavior is specific to
paths ending with :file:`/include/`; in all the other cases, the name of the
Ada specs is derived from the simple name of the header files instead.
The :switch:`-C` switch tells ``gcc`` to extract comments from headers,
-and will attempt to generate corresponding Ada comments.
+and attempt to generate corresponding Ada comments.
If you want to generate a single Ada file and not the transitive closure, you
can use instead the :switch:`-fdump-ada-spec-slim` switch.
@@ -4622,11 +4599,11 @@ is for example the case with :file:`Xlib.h` under GNU/Linux:
$ gcc -c -fdump-ada-spec -DXLIB_ILLEGAL_ACCESS -C /usr/include/X11/Xlib.h
-The above will generate more complete bindings than a straight call without
+The above generates more complete bindings than a call without
the :switch:`-DXLIB_ILLEGAL_ACCESS` switch.
-In other cases, it is not possible to parse a header file in a stand-alone
-manner, because other include files need to be included first. In this
+In other cases, you can't parse a header file in a stand-alone
+manner because other include files need to be included first. In this
case, the solution is to create a small header file including the needed
``#include`` and possible ``#define`` directives. For example, to
generate Ada bindings for :file:`readline/readline.h`, you need to first
@@ -4650,15 +4627,15 @@ and then generate Ada bindings from this file:
Generating Bindings for C++ Headers
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Generating bindings for C++ headers is done using the same options, always
-with the *g++* compiler. Note that generating Ada spec from C++ headers is a
+Generating bindings for C++ headers is done using the same options, but
+with the ``g++`` compiler. Note that generating Ada spec from C++ headers is a
much more complex job and support for C++ headers is much more limited that
support for C headers. As a result, you will need to modify the resulting
bindings by hand more extensively when using C++ headers.
-In this mode, C++ classes will be mapped to Ada tagged types, constructors
-will be mapped using the ``CPP_Constructor`` pragma, and when possible,
-multiple inheritance of abstract classes will be mapped to Ada interfaces
+In this mode, C++ classes are mapped to Ada tagged types, constructors
+are mapped using the ``CPP_Constructor`` pragma, and when possible,
+multiple inheritance of abstract classes are mapped to Ada interfaces
(see the *Interfacing to C++* section in the :title:`GNAT Reference Manual`
for additional information on interfacing to C++).
@@ -4761,8 +4738,8 @@ Switches
.. index:: -fdump-ada-spec-slim (gcc)
:switch:`-fdump-ada-spec-slim`
- Generate Ada spec files for the header files specified on the command line
- only.
+ Only generate Ada spec files for the header files specified on the
+ command line.
.. index:: -fada-spec-parent (gcc)
@@ -4783,9 +4760,9 @@ Generating C Headers for Ada Specifications
.. index:: Binding generation (for Ada specs)
.. index:: C headers (binding generation)
-GNAT includes a C header generator for Ada specifications which supports
-Ada types that have a direct mapping to C types. This includes in particular
-support for:
+GNAT includes a C header generator for Ada specifications that
+supports Ada types that have a direct mapping to C types. This
+specifically includes support for:
* Scalar types
* Constrained arrays
@@ -4799,18 +4776,18 @@ Running the C Header Generator
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The C header generator is part of the GNAT compiler and can be invoked via
-the :switch:`-gnatceg` combination of switches, which will generate a :file:`.h`
+the :switch:`-gnatceg` switch, which generates a :file:`.h`
file corresponding to the given input file (Ada spec or body). Note that
-only spec files are processed in any case, so giving a spec or a body file
+only spec files are processed, so giving a spec or a body file
as input is equivalent. For example:
.. code-block:: sh
$ gcc -c -gnatceg pack1.ads
-will generate a self-contained file called :file:`pack1.h` including
-common definitions from the Ada Standard package, followed by the
-definitions included in :file:`pack1.ads`, as well as all the other units
+generates a self-contained file called :file:`pack1.h` including
+common definitions from the Ada Standard package followed by the
+definitions included in :file:`pack1.ads` as well as all the other units
withed by this file.
For instance, given the following Ada files:
@@ -4836,7 +4813,7 @@ For instance, given the following Ada files:
procedure Proc2 (R : in out Rec);
end Pack1;
-The above ``gcc`` command will generate the following :file:`pack1.h` file:
+The above ``gcc`` command generates the following :file:`pack1.h` file:
.. code-block:: c
@@ -4867,7 +4844,7 @@ GNAT and Other Compilation Models
=================================
This section compares the GNAT model with the approaches taken in
-other environments, first the C/C++ model and then the mechanism that
+other environments: first the C/C++ model and then the mechanism that
has been used in other Ada systems, in particular those traditionally
used for Ada 83.
@@ -4876,11 +4853,10 @@ used for Ada 83.
Comparison between GNAT and C/C++ Compilation Models
----------------------------------------------------
-The GNAT model of compilation is close to the C and C++ models. You can
+The GNAT compilation model is close to the C and C++ models. You can
think of Ada specs as corresponding to header files in C. As in C, you
don't need to compile specs; they are compiled when they are used. The
-Ada |with| is similar in effect to the ``#include`` of a C
-header.
+Ada |with| is similar in effect to the ``#include`` of a C header.
One notable difference is that, in Ada, you may compile specs separately
to check them for semantic and syntactic accuracy. This is not always
@@ -4890,7 +4866,7 @@ less specific syntactic or semantic rules.
The other major difference is the requirement for running the binder,
which performs two important functions. First, it checks for
consistency. In C or C++, the only defense against assembling
-inconsistent programs lies outside the compiler, in a makefile, for
+inconsistent programs lies outside the compiler, in a :file:`makefile`, for
example. The binder satisfies the Ada requirement that it be impossible
to construct an inconsistent program when the compiler is used in normal
mode.
@@ -4919,9 +4895,9 @@ model, as described in the Ada Reference Manual.
In GNAT, there is no 'library' in the normal sense. Instead, the set of
source files themselves acts as the library. Compiling Ada programs does
not generate any centralized information, but rather an object file and
-a ALI file, which are of interest only to the binder and linker.
+a :file:`.ali` file, which are of interest only to the binder and linker.
In a traditional system, the compiler reads information not only from
-the source file being compiled, but also from the centralized library.
+the source file being compiled but also from the centralized library.
This means that the effect of a compilation depends on what has been
previously compiled. In particular:
@@ -4952,7 +4928,7 @@ files can affect the results of a compilation. In particular:
depended on the source file being modified.
The most important result of these differences is that order of compilation
-is never significant in GNAT. There is no situation in which one is
+is never significant in GNAT. There is no situation in which you are
required to do one compilation before another. What shows up as order of
compilation requirements in the traditional Ada library becomes, in
GNAT, simple source dependencies; in other words, there is only a set
@@ -4974,15 +4950,15 @@ used with tools designed for other languages.
Using Other Utility Programs with GNAT
--------------------------------------
-The object files generated by GNAT are in standard system format and in
-particular the debugging information uses this format. This means
+The object files generated by GNAT are in standard system format and, in
+particular, the debugging information uses this format. This means
programs generated by GNAT can be used with existing utilities that
depend on these formats.
In general, any utility program that works with C will also often work with
Ada programs generated by GNAT. This includes software utilities such as
-gprof (a profiling program), gdb (the FSF debugger), and utilities such
-as Purify.
+``gprof`` (a profiling program), ``gdb`` (the FSF debugger), and utilities such
+as ``Purify``.
.. _The_External_Symbol_Naming_Scheme_of_GNAT:
@@ -4990,12 +4966,12 @@ as Purify.
The External Symbol Naming Scheme of GNAT
-----------------------------------------
-In order to interpret the output from GNAT, when using tools that are
-originally intended for use with other languages, it is useful to
+To interpret the output from GNAT when using tools that are
+originally intended for use with other languages, you need to
understand the conventions used to generate link names from the Ada
entity names.
-All link names are in all lowercase letters. With the exception of library
+All link names are in all lowercase. With the exception of library
procedure names, the mechanism used is simply to use the full expanded
Ada name with dots replaced by double underscores. For example, suppose
we have the following package spec:
@@ -5010,7 +4986,7 @@ we have the following package spec:
The variable ``MN`` has a full expanded Ada name of ``QRS.MN``, so
the corresponding link name is ``qrs__mn``.
-Of course if a ``pragma Export`` is used this may be overridden:
+Of course if you use a pragma ``Export``, you maye override this:
.. code-block:: ada
@@ -5033,11 +5009,11 @@ arises between the required name ``_main`` for the C main program,
and the name we would otherwise assign to an Ada library level procedure
called ``Main`` (which might well not be the main program).
-To avoid this ambiguity, we attach the prefix ``_ada_`` to such
+To avoid this ambiguity, GNAT adds the prefix ``_ada_`` to such
names. So if we have a library level procedure such as:
.. code-block:: ada
procedure Hello (S : String);
-the external name of this procedure will be ``_ada_hello``.
+the external name of this procedure is ``_ada_hello``.
@@ -549,13 +549,13 @@ toolset for the full Ada programming language.
It documents the features of the compiler and tools, and explains
how to use them to build Ada applications.
-GNAT implements Ada 95, Ada 2005, Ada 2012, and Ada 202x, and it may also be
-invoked in Ada 83 compatibility mode.
-By default, GNAT assumes Ada 2012, but you can override with a
-compiler switch (@ref{6,,Compiling Different Versions of Ada})
-to explicitly specify the language version.
-Throughout this manual, references to ‘Ada’ without a year suffix
-apply to all Ada versions of the language, starting with Ada 95.
+GNAT implements Ada 95, Ada 2005, Ada 2012, and Ada 2022. You may
+also invoke it in Ada 83 compatibility mode. By default, GNAT assumes
+Ada 2012, but you can use a compiler switch
+(@ref{6,,Compiling Different Versions of Ada}) to explicitly specify the
+language version. Throughout this manual, references to ‘Ada’ without
+a year suffix apply to all versions of the Ada language starting with
+Ada 95.
@menu
* What This Guide Contains::
@@ -717,14 +717,14 @@ and then shown this way.
@end example
@item
-Commands that are entered by the user are shown as preceded by a prompt string
+Commands that you enter are shown as preceded by a prompt string
comprising the @code{$} character followed by a space.
@item
Full file names are shown with the ‘/’ character
as the directory separator; e.g., @code{parent-dir/subdir/myfile.adb}.
If you are using GNAT on a Windows platform, please note that
-the ‘\’ character should be used instead.
+you should use the ‘\’ character instead.
@end itemize
@node Getting Started with GNAT,The GNAT Compilation Model,About This Guide,Top
@@ -755,66 +755,67 @@ For information on GNAT Studio please refer to the
@section System Requirements
-Even though any machine can run the GNAT toolset and GNAT Studio IDE, in order
-to get the best experience, we recommend using a machine with as many cores
-as possible since all individual compilations can run in parallel.
+Even though any machine can run the GNAT toolset and GNAT Studio IDE,
+to get the best experience we recommend using a machine with as many cores
+as possible, allowing individual compilations to run in parallel.
A comfortable setup for a compiler server is a machine with 24 physical cores
or more, with at least 48 GB of memory (2 GB per core).
-For a desktop machine, a minimum of 4 cores is recommended (8 preferred),
+For a desktop machine, we recommend a minimum of 4 cores (8 is preferred),
with at least 2GB per core (so 8 to 16GB).
-In addition, for running and navigating sources in GNAT Studio smoothly, we
-recommend at least 1.5 GB plus 3 GB of RAM per 1 million source line of code.
-In other words, we recommend at least 3 GB for for 500K lines of code and
+In addition, for running and smoothly navigating sources in GNAT Studio, we
+recommend at least 1.5 GB, plus 3 GB of RAM per million source lines of code.
+So we recommend at least 3 GB for 500K lines of code and
7.5 GB for 2 million lines of code.
-Note that using local and fast drives will also make a difference in terms of
-build and link time. Network drives such as NFS, SMB, or worse, configuration
-management filesystems (such as ClearCase dynamic views) should be avoided as
-much as possible and will produce very degraded performance (typically 2 to 3
-times slower than on local fast drives). If such slow drives cannot be avoided
-for accessing the source code, then you should at least configure your project
-file so that the result of the compilation is stored on a drive local to the
-machine performing the run. This can be achieved by setting the @code{Object_Dir}
-project file attribute.
+Using fast, local drives can make a significant difference in build
+and link times. You should avoid network drives such as NFS, SMB, or
+worse, configuration management filesystems (such as ClearCase dynamic
+views) as much as possible since these will produce very degraded
+performance (typically 2 to 3 times slower than on fast, local
+drives). If you cannot avoid using such slow drives for accessing
+source code, you should at least configure your project file so
+the result of the compilation is stored on a drive local to the
+machine performing the compilation. You can do this by setting the
+@code{Object_Dir} project file attribute.
@node Running GNAT,Running a Simple Ada Program,System Requirements,Getting Started with GNAT
@anchor{gnat_ugn/getting_started_with_gnat id3}@anchor{18}@anchor{gnat_ugn/getting_started_with_gnat running-gnat}@anchor{19}
@section Running GNAT
-Three steps are needed to create an executable file from an Ada source
-file:
+You need to take three steps to create an executable file from an Ada
+source file:
@itemize *
@item
-The source file(s) must be compiled.
+You must compile the source file(s).
@item
-The file(s) must be bound using the GNAT binder.
+You must bind the file(s) using the GNAT binder.
@item
-All appropriate object files must be linked to produce an executable.
+You must link all appropriate object files to produce an executable.
@end itemize
-All three steps are most commonly handled by using the @code{gnatmake}
-utility program that, given the name of the main program, automatically
-performs the necessary compilation, binding and linking steps.
+You most commonly perform all three steps by using the @code{gnatmake}
+utility program. You pass it the name of the main program and it automatically
+performs the necessary compilation, binding, and linking steps.
@node Running a Simple Ada Program,Running a Program with Multiple Units,Running GNAT,Getting Started with GNAT
@anchor{gnat_ugn/getting_started_with_gnat id4}@anchor{1a}@anchor{gnat_ugn/getting_started_with_gnat running-a-simple-ada-program}@anchor{1b}
@section Running a Simple Ada Program
-Any text editor may be used to prepare an Ada program.
-(If Emacs is used, the optional Ada mode may be helpful in laying out the
+You may use any text editor to prepare an Ada program.
+(If you use Emacs, an optional Ada mode may be helpful in laying out the
program.)
The program text is a normal text file. We will assume in our initial
example that you have used your editor to prepare the following
-standard format text file:
+standard format text file named @code{hello.adb}:
@example
with Ada.Text_IO; use Ada.Text_IO;
@@ -824,21 +825,18 @@ begin
end Hello;
@end example
-This file should be named @code{hello.adb}.
With the normal default file naming conventions, GNAT requires
that each file
contain a single compilation unit whose file name is the
-unit name,
-with periods replaced by hyphens; the
+unit name with periods replaced by hyphens; the
extension is @code{ads} for a
spec and @code{adb} for a body.
You can override this default file naming convention by use of the
-special pragma @code{Source_File_Name} (for further information please
-see @ref{1c,,Using Other File Names}).
+special pragma @code{Source_File_Name} (see @ref{1c,,Using Other File Names}).
Alternatively, if you want to rename your files according to this default
convention, which is probably more convenient if you will be using GNAT
-for all your compilations, then the @code{gnatchop} utility
-can be used to generate correctly-named source files
+for all your compilations, then you use can use the @code{gnatchop} utility
+to generate correctly-named source files
(see @ref{1d,,Renaming Files with gnatchop}).
You can compile the program using the following command (@code{$} is used
@@ -848,16 +846,16 @@ as the command prompt in the examples in this document):
$ gcc -c hello.adb
@end example
-@code{gcc} is the command used to run the compiler. This compiler is
+@code{gcc} is the command used to run the compiler. It is
capable of compiling programs in several languages, including Ada and
-C. It assumes that you have given it an Ada program if the file extension is
-either @code{.ads} or @code{.adb}, and it will then call
+C. It assumes you have given it an Ada program if the file extension is
+either @code{.ads} or @code{.adb}, in which case it will call
the GNAT compiler to compile the specified file.
The @code{-c} switch is required. It tells @code{gcc} to only do a
compilation. (For C programs, @code{gcc} can also do linking, but this
-capability is not used directly for Ada programs, so the @code{-c}
-switch must always be present.)
+capability is not used directly for Ada programs, so you must always
+specify the @code{-c}.)
This compile command generates a file
@code{hello.o}, which is the object
@@ -866,11 +864,11 @@ an ‘Ada Library Information’ file @code{hello.ali},
which contains additional information used to check
that an Ada program is consistent.
-To build an executable file, use either @code{gnatmake} or gprbuild with
-the name of the main file: these tools are builders that will take care of
+To build an executable file, use either @code{gnatmake} or @code{gprbuild} with
+the name of the main file: these tools are builders that perform
all the necessary build steps in the correct order.
In particular, these builders automatically recompile any sources that have
-been modified since they were last compiled, or sources that depend
+been modified since they were last compiled, as well as sources that depend
on such modified sources, so that ‘version skew’ is avoided.
@geindex Version skew (avoided by `@w{`}gnatmake`@w{`})
@@ -879,7 +877,7 @@ on such modified sources, so that ‘version skew’ is avoided.
$ gnatmake hello.adb
@end example
-The result is an executable program called @code{hello}, which can be
+The result is an executable program called @code{hello}, which you can
run by entering:
@example
@@ -902,8 +900,8 @@ appear in response to this command.
@section Running a Program with Multiple Units
-Consider a slightly more complicated example that has three files: a
-main program, and the spec and body of a package:
+Consider a slightly more complicated example with three files: a
+main program and the spec and body of a package:
@example
package Greetings is
@@ -954,15 +952,15 @@ body of main program
Note that there is no required order of compilation when using GNAT.
In particular it is perfectly fine to compile the main program first.
Also, it is not necessary to compile package specs in the case where
-there is an accompanying body; you only need to compile the body. If you want
+there is an accompanying body; you only need compile the body. If you want
to submit these files to the compiler for semantic checking and not code
-generation, then use the @code{-gnatc} switch:
+generation, use the @code{-gnatc} switch:
@example
$ gcc -c greetings.ads -gnatc
@end example
-Although the compilation can be done in separate steps, in practice it is
+Although you can do the compilation in separate steps, in practice it’s
almost always more convenient to use the @code{gnatmake} or @code{gprbuild} tools:
@example
@@ -1068,7 +1066,7 @@ Topics related to source file makeup and naming
Ada source programs are represented in standard text files, using
Latin-1 coding. Latin-1 is an 8-bit code that includes the familiar
-7-bit ASCII set, plus additional characters used for
+7-bit ASCII set plus additional characters used for
representing foreign languages (see @ref{23,,Foreign Language Representation}
for support of non-USA character sets). The format effector characters
are represented using their standard ASCII encodings, as follows:
@@ -1153,11 +1151,11 @@ Form feed
@end quotation
-Source files are in standard text file format. In addition, GNAT will
-recognize a wide variety of stream formats, in which the end of
+Source files are in standard text file format. In addition, GNAT
+recognizes a wide variety of stream formats, in which the end of
physical lines is marked by any of the following sequences:
@code{LF}, @code{CR}, @code{CR-LF}, or @code{LF-CR}. This is useful
-in accommodating files that are imported from other operating systems.
+in accommodating files imported from other operating systems.
@geindex End of source file; Source file@comma{} end
@@ -1166,7 +1164,7 @@ in accommodating files that are imported from other operating systems.
The end of a source file is normally represented by the physical end of
file. However, the control character @code{16#1A#} (@code{SUB}) is also
recognized as signalling the end of the source file. Again, this is
-provided for compatibility with other operating systems where this
+provided for compatibility with other, legacy, operating systems where this
code is used to represent the end of file.
@geindex spec (definition)
@@ -1177,7 +1175,7 @@ associated with the unit. For example, this means you must place a
package declaration (a package `spec') and the corresponding body in
separate files. An Ada `compilation' (which is a sequence of
compilation units) is represented using a sequence of files. Similarly,
-you will place each subunit or child unit in a separate file.
+you place each subunit or child unit in a separate file.
@node Foreign Language Representation,File Naming Topics and Utilities,Source Representation,The GNAT Compilation Model
@anchor{gnat_ugn/the_gnat_compilation_model foreign-language-representation}@anchor{23}@anchor{gnat_ugn/the_gnat_compilation_model id3}@anchor{30}
@@ -1205,7 +1203,7 @@ of the compiler (@ref{31,,Character Set Control}).
The basic character set is Latin-1. This character set is defined by ISO
standard 8859, part 1. The lower half (character codes @code{16#00#}
-… @code{16#7F#)} is identical to standard ASCII coding, but the upper
+… @code{16#7F#)} is identical to standard ASCII coding but the upper
half is used to represent additional characters. These include extended letters
used by European languages, such as French accents, the vowels with umlauts
used in German, and the extra letter A-ring used in Swedish.
@@ -1298,7 +1296,7 @@ lowercase equivalence.
@item `IBM PC (code page 437)'
-This code page is the normal default for PCs in the U.S. It corresponds
+This code page is the normal default for PCs in the US. It corresponds
to the original IBM PC character set. This set has some, but not all, of
the extended Latin-1 letters, but these letters do not have the same
encoding as Latin-1. In this mode, these letters are allowed in
@@ -1319,7 +1317,7 @@ lowercase equivalence.
@item `Full Upper 8-bit'
-Any character in the range 80-FF allowed in identifiers, and all are
+Any character in the range 80-FF is allowed in identifiers and all are
considered distinct. In other words, there are no uppercase and lowercase
equivalences in this range. This is useful in conjunction with
certain encoding schemes used for some foreign character sets (e.g.,
@@ -1391,8 +1389,8 @@ A wide character is represented by a two-character sequence,
@code{16#cd#}, with the restrictions described for upper-half encoding as
described above. The internal character code is the corresponding JIS
character according to the standard algorithm for Shift-JIS
-conversion. Only characters defined in the JIS code set table can be
-used with this encoding method.
+conversion. You can only use characters defined in the JIS code set table
+with this encoding method.
@end table
@geindex EUC Coding
@@ -1403,11 +1401,10 @@ used with this encoding method.
@item `EUC Coding'
A wide character is represented by a two-character sequence
-@code{16#ab#} and
-@code{16#cd#}, with both characters being in the upper half. The internal
-character code is the corresponding JIS character according to the EUC
-encoding algorithm. Only characters defined in the JIS code set table
-can be used with this encoding method.
+@code{16#ab#} and @code{16#cd#}, with both characters being in the upper
+half. The internal character code is the corresponding JIS character
+according to the EUC encoding algorithm. You can only use characters
+defined in the JIS code set table with this encoding method.
@item `UTF-8 Coding'
@@ -1427,8 +1424,8 @@ where the @code{xxx} bits correspond to the left-padded bits of the
are represented as ASCII bytes and all upper half characters and
other wide characters are represented as sequences of upper-half
(The full UTF-8 scheme allows for encoding 31-bit characters as
-6-byte sequences, and in the following section on wide wide
-characters, the use of these sequences is documented).
+6-byte sequences the use of these sequences is documented in the
+following section on wide wide characters.)
@item `Brackets Coding'
@@ -1439,14 +1436,14 @@ character sequence:
[ " a b c d " ]
@end example
-where @code{a}, @code{b}, @code{c}, @code{d} are the four hexadecimal
-characters (using uppercase letters) of the wide character code. For
-example, [‘A345’] is used to represent the wide character with code
-@code{16#A345#}. It is also possible (though not required) to use the
-Brackets coding for upper half characters. For example, the code
-@code{16#A3#} can be represented as @code{['A3']}.
+where @code{a}, @code{b}, @code{c}, @code{d} are the four hexadecimal characters
+(using uppercase letters) of the wide character code. For example,
+[‘A345’] is used to represent the wide character with code
+@code{16#A345#}. You can also (though you are not required to) use the
+Brackets coding for upper half characters. For example, you can
+represent the code @code{16#A3#} as @code{['A3']}.
-This scheme is compatible with use of the full Wide_Character set,
+This scheme is compatible with use of the full @code{Wide_Character} set,
and is also the method used for wide character encoding in some standard
ACATS (Ada Conformity Assessment Test Suite) test suite distributions.
@end table
@@ -1506,7 +1503,7 @@ characters (using uppercase letters) of the wide wide character code. For
example, [“1F4567”] is used to represent the wide wide character with code
@code{16#001F_4567#}.
-This scheme is compatible with use of the full Wide_Wide_Character set,
+This scheme is compatible with use of the full @code{Wide_Wide_Character} set,
and is also the method used for wide wide character encoding in some standard
ACATS (Ada Conformity Assessment Test Suite) test suite distributions.
@end table
@@ -1516,9 +1513,10 @@ ACATS (Ada Conformity Assessment Test Suite) test suite distributions.
@section File Naming Topics and Utilities
-GNAT has a default file naming scheme and also provides the user with
-a high degree of control over how the names and extensions of the
-source files correspond to the Ada compilation units that they contain.
+GNAT has a default file naming scheme, but and also provides you
+with a high degree of control over how the names and extensions of your
+source files correspond to the Ada compilation units that they
+contain.
@menu
* File Naming Rules::
@@ -1535,18 +1533,18 @@ source files correspond to the Ada compilation units that they contain.
@subsection File Naming Rules
-The default file name is determined by the name of the unit that the
+GNAT determines the default file name by the name of the unit that the
file contains. The name is formed by taking the full expanded name of
-the unit and replacing the separating dots with hyphens and using
+the unit, replacing the separating dots with hyphens, and using
lowercase for all letters.
-An exception arises if the file name generated by the above rules starts
+An exception occurs if the file name generated by the above rules starts
with one of the characters
-@code{a}, @code{g}, @code{i}, or @code{s}, and the second character is a
-minus. In this case, the character tilde is used in place
-of the minus. The reason for this special rule is to avoid clashes with
-the standard names for child units of the packages System, Ada,
-Interfaces, and GNAT, which use the prefixes
+@code{a}, @code{g}, @code{i}, or @code{s} and the second character is a
+hyphen. In this case, the character tilde is used in place
+of the hypen. This special rule avoids clashes with
+the standard names for child units of the packages @code{System}, @code{Ada},
+@code{Interfaces}, and @code{GNAT}, which use the prefixes
@code{s-}, @code{a-}, @code{i-}, and @code{g-},
respectively.
@@ -1638,23 +1636,23 @@ Following these rules can result in excessively long
file names if corresponding
unit names are long (for example, if child units or subunits are
heavily nested). An option is available to shorten such long file names
-(called file name ‘krunching’). This may be particularly useful when
+(called file name ‘krunching’). You may find this particularly useful when
programs being developed with GNAT are to be used on operating systems
with limited file name lengths. @ref{3d,,Using gnatkr}.
Of course, no file shortening algorithm can guarantee uniqueness over
all possible unit names; if file name krunching is used, it is your
-responsibility to ensure no name clashes occur. Alternatively you
+responsibility to ensure no name clashes occur. Alternatively, you
can specify the exact file names that you want used, as described
in the next section. Finally, if your Ada programs are migrating from a
-compiler with a different naming convention, you can use the gnatchop
+compiler with a different naming convention, you can use the @code{gnatchop}
utility to produce source files that follow the GNAT naming conventions.
(For details see @ref{1d,,Renaming Files with gnatchop}.)
Note: in the case of Windows or Mac OS operating systems, case is not
-significant. So for example on Windows if the canonical name is
+significant. So, for example, on Windows if the canonical name is
@code{main-sub.adb}, you can use the file name @code{Main-Sub.adb} instead.
-However, case is significant for other operating systems, so for example,
+However, case is significant for other operating systems, so, for example,
if you want to use other than canonically cased file names on a Unix system,
you need to follow the procedures described in the next section.
@@ -1665,18 +1663,18 @@ you need to follow the procedures described in the next section.
@geindex File names
-In the previous section, we have described the default rules used by
+The previous section described the default rules used by
GNAT to determine the file name in which a given unit resides. It is
-often convenient to follow these default rules, and if you follow them,
+usually convenient to follow these default rules, and if you follow them,
the compiler knows without being explicitly told where to find all
the files it needs.
@geindex Source_File_Name pragma
However, in some cases, particularly when a program is imported from
-another Ada compiler environment, it may be more convenient for the
-programmer to specify which file names contain which units. GNAT allows
-arbitrary file names to be used by means of the Source_File_Name pragma.
+another Ada compiler environment, it may be more convenient for you
+to specify which file names contain which units. GNAT allows
+arbitrary file names to be used by means of the @code{Source_File_Name} pragma.
The form of this pragma is as shown in the following examples:
@example
@@ -1693,7 +1691,7 @@ indicates whether the file name is for a spec or a body;
the file name itself is given by a string literal.
The source file name pragma is a configuration pragma, which means that
-normally it will be placed in the @code{gnat.adc}
+normally you will place it in the @code{gnat.adc}
file used to hold configuration
pragmas that apply to a complete compilation environment.
For more details on how the @code{gnat.adc} file is created and used
@@ -1701,12 +1699,12 @@ see @ref{3f,,Handling of Configuration Pragmas}.
@geindex gnat.adc
-GNAT allows completely arbitrary file names to be specified using the
+GNAT allows you to specify completely arbitrary file names using the
source file name pragma. However, if the file name specified has an
-extension other than @code{.ads} or @code{.adb} it is necessary to use
-a special syntax when compiling the file. The name in this case must be
-preceded by the special sequence @code{-x} followed by a space and the name
-of the language, here @code{ada}, as in:
+extension other than @code{.ads} or @code{.adb} you must use a
+special syntax when compiling the file. The name on the command line
+in this case must be preceded by the special sequence @code{-x} followed
+by a space and the name of the language, here @code{ada}, as in:
@example
$ gcc -c -x ada peculiar_file_name.sim
@@ -1714,8 +1712,8 @@ $ gcc -c -x ada peculiar_file_name.sim
@code{gnatmake} handles non-standard file names in the usual manner (the
non-standard file name for the main program is simply used as the
-argument to gnatmake). Note that if the extension is also non-standard,
-then it must be included in the @code{gnatmake} command, it may not
+argument to @code{gnatmake}). Note that if the extension is also non-standard,
+you must include it in the @code{gnatmake} command; it may not
be omitted.
@node Alternative File Naming Schemes,Handling Arbitrary File Naming Conventions with gnatname,Using Other File Names,File Naming Topics and Utilities
@@ -1730,8 +1728,8 @@ be omitted.
The previous section described the use of the @code{Source_File_Name}
pragma to allow arbitrary names to be assigned to individual source files.
-However, this approach requires one pragma for each file, and especially in
-large systems can result in very long @code{gnat.adc} files, and also create
+However, this approach requires one pragma for each file and, especially in
+large systems, can result in very long @code{gnat.adc} files, which can create
a maintenance problem.
@geindex Source_File_Name pragma
@@ -1767,55 +1765,53 @@ systematically for this asterisk. The optional parameter
@code{Casing} indicates
whether the unit name is to be all upper-case letters, all lower-case letters,
or mixed-case. If no
-@code{Casing} parameter is used, then the default is all
+@code{Casing} parameter is used, the default is all
lower-case.
-The optional @code{Dot_Replacement} string is used to replace any periods
-that occur in subunit or child unit names. If no @code{Dot_Replacement}
-argument is used then separating dots appear unchanged in the resulting
-file name.
-Although the above syntax indicates that the
-@code{Casing} argument must appear
-before the @code{Dot_Replacement} argument, but it
-is also permissible to write these arguments in the opposite order.
-
-As indicated, it is possible to specify different naming schemes for
-bodies, specs, and subunits. Quite often the rule for subunits is the
-same as the rule for bodies, in which case, there is no need to give
-a separate @code{Subunit_File_Name} rule, and in this case the
+You use the optional @code{Dot_Replacement} string to replace any periods
+that occur in subunit or child unit names. If you don’t specify a
+@code{Dot_Replacement} argument, separating dots appear unchanged in the
+resulting file name. The above syntax indicates that the @code{Casing}
+argument must appear before the @code{Dot_Replacement} argument, but you
+can write these arguments in any order.
+
+As indicated, you can specify different naming schemes for
+bodies, specs, and subunits. Quite often, the rule for subunits is the
+same as the rule for bodies, in which case, you need not provide
+a separate @code{Subunit_File_Name} rule; in this case the
@code{Body_File_name} rule is used for subunits as well.
-The separate rule for subunits can also be used to implement the rather
+You can also use the separate rule for subunits to implement the rather
unusual case of a compilation environment (e.g., a single directory) which
contains a subunit and a child unit with the same unit name. Although
both units cannot appear in the same partition, the Ada Reference Manual
allows (but does not require) the possibility of the two units coexisting
in the same environment.
-The file name translation works in the following steps:
+File name translation consists of the following steps:
@itemize *
@item
If there is a specific @code{Source_File_Name} pragma for the given unit,
-then this is always used, and any general pattern rules are ignored.
+this is always used and any general pattern rules are ignored.
@item
If there is a pattern type @code{Source_File_Name} pragma that applies to
-the unit, then the resulting file name will be used if the file exists. If
-more than one pattern matches, the latest one will be tried first, and the
-first attempt resulting in a reference to a file that exists will be used.
+the unit, the resulting file name is used if the file exists. If
+more than one pattern matches, the latest one is tried first and the
+first attempt that results in a reference to a file that exists is used.
@item
If no pattern type @code{Source_File_Name} pragma that applies to the unit
-for which the corresponding file exists, then the standard GNAT default
+for which the corresponding file exists, the standard GNAT default
naming rules are used.
@end itemize
As an example of the use of this mechanism, consider a commonly used scheme
in which file names are all lower case, with separating periods copied
-unchanged to the resulting file name, and specs end with @code{.1.ada}, and
+unchanged to the resulting file name, specs end with @code{.1.ada}, and
bodies end with @code{.2.ada}. GNAT will follow this scheme if the following
two pragmas appear:
@@ -1826,8 +1822,8 @@ pragma Source_File_Name
(Body_File_Name => ".2.ada");
@end example
-The default GNAT scheme is actually implemented by providing the following
-default pragmas internally:
+The default GNAT scheme is equivalent to providing the following
+default pragmas:
@example
pragma Source_File_Name
@@ -1837,11 +1833,11 @@ pragma Source_File_Name
@end example
Our final example implements a scheme typically used with one of the
-Ada 83 compilers, where the separator character for subunits was ‘__’
+legacy Ada 83 compilers, where the separator character for subunits was ‘__’
(two underscores), specs were identified by adding @code{_.ADA}, bodies
by adding @code{.ADA}, and subunits by
adding @code{.SEP}. All file names were
-upper case. Child units were not present of course since this was an
+upper case. Child units were not present, of course, since this was an
Ada 83 compiler, but it seems reasonable to extend this scheme to use
the same double underscore separator for child units.
@@ -1882,24 +1878,23 @@ pragma Source_File_Name
@subsubsection Arbitrary File Naming Conventions
-The GNAT compiler must be able to know the source file name of a compilation
-unit. When using the standard GNAT default file naming conventions
-(@code{.ads} for specs, @code{.adb} for bodies), the GNAT compiler
+The GNAT compiler must know the source file name of a compilation unit
+in order to compile it. When using the standard GNAT default file
+naming conventions (@code{.ads} for specs, @code{.adb} for bodies), it
does not need additional information.
-When the source file names do not follow the standard GNAT default file naming
-conventions, the GNAT compiler must be given additional information through
-a configuration pragmas file (@ref{25,,Configuration Pragmas})
-or a project file.
-When the non-standard file naming conventions are well-defined,
-a small number of pragmas @code{Source_File_Name} specifying a naming pattern
+When the source file names do not follow the standard GNAT default
+file naming conventions, you must give the GNAT compiler additional
+information through a configuration pragmas file
+(@ref{25,,Configuration Pragmas}) or a project file. When the
+non-standard file naming conventions are well-defined, a small number
+of pragmas @code{Source_File_Name} specifying a naming pattern
(@ref{40,,Alternative File Naming Schemes}) may be sufficient. However,
-if the file naming conventions are irregular or arbitrary, a number
-of pragma @code{Source_File_Name} for individual compilation units
-must be defined.
-To help maintain the correspondence between compilation unit names and
-source file names within the compiler,
-GNAT provides a tool @code{gnatname} to generate the required pragmas for a
+if the file naming conventions are irregular or arbitrary, you must
+define a number of pragma @code{Source_File_Name} for individual
+compilation units. To help maintain the correspondence between
+compilation unit names and source file names within the compiler, GNAT
+provides a tool @code{gnatname} to generate the required pragmas for a
set of files.
@node Running gnatname,Switches for gnatname,Arbitrary File Naming Conventions,Handling Arbitrary File Naming Conventions with gnatname
@@ -1914,27 +1909,28 @@ $ gnatname [ switches ] naming_pattern [ naming_patterns ]
[--and [ switches ] naming_pattern [ naming_patterns ]]
@end example
-All of the arguments are optional. If invoked without any argument,
+All of the arguments are optional. If invoked without any arguments,
@code{gnatname} will display its usage.
-When used with at least one naming pattern, @code{gnatname} will attempt to
+When used with at least one naming pattern, @code{gnatname} attempts to
find all the compilation units in files that follow at least one of the
naming patterns. To find these compilation units,
-@code{gnatname} will use the GNAT compiler in syntax-check-only mode on all
+@code{gnatname} uses the GNAT compiler in syntax-check-only mode on all
regular files.
-One or several Naming Patterns may be given as arguments to @code{gnatname}.
+One or several `Naming Patterns' may be given as arguments to @code{gnatname}.
Each Naming Pattern is enclosed between double quotes (or single
quotes on Windows).
A Naming Pattern is a regular expression similar to the wildcard patterns
used in file names by the Unix shells or the DOS prompt.
-@code{gnatname} may be called with several sections of directories/patterns.
-Sections are separated by the switch @code{--and}. In each section, there must be
-at least one pattern. If no directory is specified in a section, the current
-directory (or the project directory if @code{-P} is used) is implied.
-The options other that the directory switches and the patterns apply globally
-even if they are in different sections.
+You may call @code{gnatname} with several sections of
+directories/patterns. Sections are separated by the switch
+@code{--and}. In each section, you must include at least one
+pattern. If you don’t specify a directory a section, the current
+directory (or the project directory if @code{-P} is used) is
+used. The options other that the directory switches and the
+patterns apply globally even if they are in different sections.
Examples of Naming Patterns are:
@@ -1969,7 +1965,7 @@ You may specify any of the following switches to @code{gnatname}:
@item @code{--version}
-Display Copyright and version, then exit disregarding all other options.
+Display Copyright and version, then exit disregarding, all other options.
@end table
@geindex --help (gnatname)
@@ -1979,12 +1975,12 @@ Display Copyright and version, then exit disregarding all other options.
@item @code{--help}
-If @code{--version} was not used, display usage, then exit disregarding
+If @code{--version} was not used, display usage, then exit, disregarding
all other options.
@item @code{--subdirs=`dir'}
-Real object, library or exec directories are subdirectories <dir> of the
+Actual object, library or exec directories are subdirectories <dir> of the
specified ones.
@item @code{--no-backup}
@@ -2005,12 +2001,12 @@ Start another section of directories/patterns.
Create a configuration pragmas file @code{filename} (instead of the default
@code{gnat.adc}).
-There may be zero, one or more space between @code{-c} and
+There may be zero, one, or more space between @code{-c} and
@code{filename}.
@code{filename} may include directory information. @code{filename} must be
-writable. There may be only one switch @code{-c}.
+writable. You can specify only one switch @code{-c}.
When a switch @code{-c} is
-specified, no switch @code{-P} may be specified (see below).
+specified, you may not specify switch @code{-P} (see below).
@end table
@geindex -d (gnatname)
@@ -2020,25 +2016,25 @@ specified, no switch @code{-P} may be specified (see below).
@item @code{-d`dir'}
-Look for source files in directory @code{dir}. There may be zero, one or more
+Look for source files in directory @code{dir}. You may put zero, one or more
spaces between @code{-d} and @code{dir}.
-@code{dir} may end with @code{/**}, that is it may be of the form
+@code{dir} may end with @code{/**}, i.e., you may write it the form
@code{root_dir/**}. In this case, the directory @code{root_dir} and all of its
subdirectories, recursively, have to be searched for sources.
-When a switch @code{-d}
-is specified, the current working directory will not be searched for source
-files, unless it is explicitly specified with a @code{-d}
+When you specify a @code{-d} switch,
+the current working directory will is not searched for source
+files unless you explicitly specify it with a @code{-d}
or @code{-D} switch.
-Several switches @code{-d} may be specified.
+You may specify several switches @code{-d}.
If @code{dir} is a relative path, it is relative to the directory of
the configuration pragmas file specified with switch
@code{-c},
or to the directory of the project file specified with switch
@code{-P} or,
-if neither switch @code{-c}
-nor switch @code{-P} are specified, it is relative to the
+if you don’t specify either switch @code{-c}
+or switch @code{-P}, it’s relative to the
current working directory. The directory
-specified with switch @code{-d} must exist and be readable.
+you specified with switch @code{-d} must exist and be readable.
@end table
@geindex -D (gnatname)
@@ -2049,7 +2045,7 @@ specified with switch @code{-d} must exist and be readable.
@item @code{-D`filename'}
Look for source files in all directories listed in text file @code{filename}.
-There may be zero, one or more spaces between @code{-D}
+You may place zero, one or more spaces between @code{-D}
and @code{filename}.
@code{filename} must be an existing, readable text file.
Each nonempty line in @code{filename} must be a directory.
@@ -2065,18 +2061,18 @@ Follow symbolic links when processing project files.
@item @code{-f`pattern'}
-Foreign patterns. Using this switch, it is possible to add sources of languages
-other than Ada to the list of sources of a project file.
-It is only useful if a -P switch is used.
+Foreign patterns. Using this switch, you can add sources of languages
+other than Ada to the list of sources of a project file, but
+it’s only useful if you also specify a @code{-P} switch.
For example,
@example
gnatname -Pprj -f"*.c" "*.ada"
@end example
-will look for Ada units in all files with the @code{.ada} extension,
-and will add to the list of file for project @code{prj.gpr} the C files
-with extension @code{.c}.
+looks for Ada units in all files with the @code{.ada} extension,
+and adds the C files with extension @code{.c} to the list of file
+for project @code{prj.gpr} .
@geindex -h (gnatname)
@@ -2085,29 +2081,36 @@ with extension @code{.c}.
Output usage (help) information. The output is written to @code{stdout}.
@geindex -P (gnatname)
+@end table
-@item @code{-P`proj'}
+@code{-P`proj'}
-Create or update project file @code{proj}. There may be zero, one or more space
-between @code{-P} and @code{proj}. @code{proj} may include directory
-information. @code{proj} must be writable.
-There may be only one switch @code{-P}.
-When a switch @code{-P} is specified,
-no switch @code{-c} may be specified.
-On all platforms, except on VMS, when @code{gnatname} is invoked for an
-existing project file <proj>.gpr, a backup copy of the project file is created
-in the project directory with file name <proj>.gpr.saved_x. ‘x’ is the first
-non negative number that makes this backup copy a new file.
+@quotation
+
+Create or update project file @code{proj}. You may place zero, one
+or more space between @code{-P} and @code{proj}. @code{proj}
+may include directory information. @code{proj} must be writable.
+There may be only one switch @code{-P}. When you specify switch
+@code{-P}, you may not also include switch @code{-c}. On all
+platforms except VMS when @code{gnatname} is invoked for an existing
+project file @code{<proj>.gpr`}, @code{gnatname} creates a backup copy
+of the project file in the project directory with file name
+@code{<proj>.gpr.saved_x} where @code{x} is the first non negative
+number that creates a unique filename.
@geindex -v (gnatname)
+@end quotation
+
+
+@table @asis
@item @code{-v}
-Verbose mode. Output detailed explanation of behavior to @code{stdout}.
-This includes name of the file written, the name of the directories to search
+Verbose mode. Output detailed explanation of what it’s doing to @code{stdout}.
+This includes name of the file written, the name of the directories searched,
and, for each file in those directories whose name matches at least one of
the Naming Patterns, an indication of whether the file contains a unit,
-and if so the name of the unit.
+and, if so, the name of the unit.
@end table
@geindex -v -v (gnatname)
@@ -2117,22 +2120,23 @@ and if so the name of the unit.
@item @code{-v -v}
-Very Verbose mode. In addition to the output produced in verbose mode,
+Very verbose mode. In addition to the output produced in verbose mode
+(a single @code{-v} switch),
for each file in the searched directories whose name matches none of
-the Naming Patterns, an indication is given that there is no match.
+the Naming Patterns, @code{gnatname} indicates that there is no match.
@geindex -x (gnatname)
@item @code{-x`pattern'}
-Excluded patterns. Using this switch, it is possible to exclude some files
-that would match the name patterns. For example,
+Excluded patterns. Using this switch, you can exclude some files
+that otherwise would match the name patterns. For example,
@example
gnatname -x "*_nt.ada" "*.ada"
@end example
-will look for Ada units in all files with the @code{.ada} extension,
+looks for Ada units in all files with the @code{.ada} extension,
except those whose names end with @code{_nt.ada}.
@end table
@@ -2157,10 +2161,9 @@ $ gnatname -P/home/me/proj -x "*_nt_body.ada"
-dsources -dsources/plus -Dcommon_dirs.txt "body_*" "spec_*"
@end example
-Note that several switches @code{-d} may be used,
-even in conjunction with one or several switches
-@code{-D}. Several Naming Patterns and one excluded pattern
-are used in this example.
+Note that you may use several @code{-d} switches, even in
+conjunction with one or several @code{-D} switches. This example
+illustrates multiple Naming Patterns and one excluded pattern.
@node File Name Krunching with gnatkr,Renaming Files with gnatchop,Handling Arbitrary File Naming Conventions with gnatname,File Naming Topics and Utilities
@anchor{gnat_ugn/the_gnat_compilation_model file-name-krunching-with-gnatkr}@anchor{4c}@anchor{gnat_ugn/the_gnat_compilation_model id17}@anchor{4d}
@@ -2169,10 +2172,10 @@ are used in this example.
@geindex gnatkr
-This section discusses the method used by the compiler to shorten
+Here we discuss the method used by the compiler to shorten
the default file names chosen for Ada units so that they do not
-exceed the maximum length permitted. It also describes the
-@code{gnatkr} utility that can be used to determine the result of
+exceed the maximum length permitted. We also describe the
+@code{gnatkr} utility, which you can use to determine the result of
applying this shortening.
@menu
@@ -2188,9 +2191,8 @@ applying this shortening.
@subsubsection About @code{gnatkr}
-The default file naming rule in GNAT
-is that the file name must be derived from
-the unit name. The exact default rule is as follows:
+GNAT requires that the file name must be derived from the unit
+name. The default rule is as follows:
@itemize *
@@ -2204,9 +2206,9 @@ second character position of a name, and the first character is
@code{a}, @code{g}, @code{s}, or @code{i},
then replace the dot by the character
@code{~} (tilde)
-instead of a minus.
+instead of a hyphen.
-The reason for this exception is to avoid clashes
+This exception avoids clashes
with the standard names for children of System, Ada, Interfaces,
and GNAT, which use the prefixes
@code{s-}, @code{a-}, @code{i-}, and @code{g-},
@@ -2215,44 +2217,45 @@ respectively.
The @code{-gnatk`nn'}
switch of the compiler activates a ‘krunching’
-circuit that limits file names to nn characters (where nn is a decimal
+circuit that limits file names to @code{nn} characters (where @code{nn} is a decimal
integer).
-The @code{gnatkr} utility can be used to determine the krunched name for
-a given file, when krunched to a specified maximum length.
+You can use the @code{gnatkr} utility to determine the krunched name for
+a given file when krunched to a specified maximum length.
@node Using gnatkr,Krunching Method,About gnatkr,File Name Krunching with gnatkr
@anchor{gnat_ugn/the_gnat_compilation_model id19}@anchor{50}@anchor{gnat_ugn/the_gnat_compilation_model using-gnatkr}@anchor{3d}
@subsubsection Using @code{gnatkr}
-The @code{gnatkr} command has the form:
+You invoke the @code{gnatkr} command as follows:
@example
$ gnatkr name [ length ]
@end example
@code{name} is the uncrunched file name, derived from the name of the unit
-in the standard manner described in the previous section (i.e., in particular
-all dots are replaced by hyphens). The file name may or may not have an
+in the default manner described in the previous section (i.e., in particular
+all dots are replaced by hyphens). You may or may not include an
extension (defined as a suffix of the form period followed by arbitrary
-characters other than period). If an extension is present then it will
-be preserved in the output. For example, when krunching @code{hellofile.ads}
-to eight characters, the result will be hellofil.ads.
+characters other than period) in the filename. If you do, @code{gnatkr} will
+preserve it in the output. For example, when krunching @code{hellofile.ads}
+to eight characters, the result will be @code{hellofil.ads}.
-Note: for compatibility with previous versions of @code{gnatkr} dots may
-appear in the name instead of hyphens, but the last dot will always be
-taken as the start of an extension. So if @code{gnatkr} is given an argument
-such as @code{Hello.World.adb} it will be treated exactly as if the first
-period had been a hyphen, and for example krunching to eight characters
-gives the result @code{hellworl.adb}.
+Note: for compatibility with previous versions of @code{gnatkr}, you can
+use dots in the name instead of hyphens, but @code{gnatkr} always
+interprets the last dot as the start of an extension. So if you pass @code{gnatkr}
+an argument such as @code{Hello.World.adb}, it treats it
+exactly as if the first period had been a hyphen, so, for
+example, krunching to eight characters gives the result
+@code{hellworl.adb}.
-Note that the result is always all lower case.
-Characters of the other case are folded as required.
+Note that the result is always all lower case. Other characters are
+folded as required.
@code{length} represents the length of the krunched name. The default
-when no argument is given is 8 characters. A length of zero stands for
-unlimited, in other words do not chop except for system files where the
+if you don’t specify it, is 8 characters. A length of zero means
+unlimited, in other words don’t chop except for system files where the
implied crunching length is always eight characters.
The output is the krunched name. The output has an extension only if the
@@ -2279,17 +2282,17 @@ the specified length by following these rules:
@itemize *
@item
-The name is divided into segments separated by hyphens, tildes or
+The name is divided into segments separated by hyphens, tildes, or
underscores and all hyphens, tildes, and underscores are
eliminated. If this leaves the name short enough, we are done.
@item
If the name is too long, the longest segment is located (left-most
-if there are two of equal length), and shortened by dropping
+if there are two of equal length) and shortened by dropping
its last character. This is repeated until the name is short enough.
As an example, consider the krunching of @code{our-strings-wide_fixed.adb}
-to fit the name into 8 characters as required by some operating systems:
+to fit the name into 8 characters, as required by some operating systems:
@example
our-strings-wide_fixed 22
@@ -2358,9 +2361,9 @@ Replacement
@end multitable
-These system files have a hyphen in the second character position. That
-is why normal user files replace such a character with a
-tilde, to avoid confusion with system file names.
+These system files have a hyphen in the second character
+position. That’s is why normal user files replace such a character
+with a tilde.
As an example of this special rule, consider
@code{ada-strings-wide_fixed.adb}, which gets krunched as follows:
@@ -2382,10 +2385,10 @@ Final file name: a-stwifi.adb
@end example
@end itemize
-Of course no file shortening algorithm can guarantee uniqueness over all
-possible unit names, and if file name krunching is used then it is your
+Of course, no file shortening algorithm can guarantee uniqueness over all
+possible unit names. If file name krunching is used, it’is your
responsibility to ensure that no name clashes occur. The utility
-program @code{gnatkr} is supplied for conveniently determining the
+program @code{gnatkr} is supplied so that you can conveniently determine the
krunched name of a file.
@node Examples of gnatkr Usage,,Krunching Method,File Name Krunching with gnatkr
@@ -2410,7 +2413,7 @@ $ gnatkr very_long_unit_name.ads/count=0 --> very_long_unit_name.ads
@geindex gnatchop
This section discusses how to handle files with multiple units by using
-the @code{gnatchop} utility. This utility is also useful in renaming
+the @code{gnatchop} utility. You will also find this utility useful in renaming
files to meet the standard GNAT default file naming conventions.
@menu
@@ -2427,27 +2430,28 @@ files to meet the standard GNAT default file naming conventions.
@subsubsection Handling Files with Multiple Units
-The basic compilation model of GNAT requires that a file submitted to the
-compiler have only one unit and there be a strict correspondence
+GNAT’s fundamental compilation model requires that a file submitted to the
+compiler contain only one unit and there be a strict correspondence
between the file name and the unit name.
-If you want to keep your files with multiple units,
+If you want to have your files contain multiple units,
perhaps to maintain compatibility with some other Ada compilation system,
-you can use @code{gnatname} to generate or update your project files.
-Generated or modified project files can be processed by GNAT.
+you can use @code{gnatname} to generate or update your project files, which
+can be processed by GNAT.
See @ref{42,,Handling Arbitrary File Naming Conventions with gnatname}
for more details on how to use @cite{gnatname}.
-Alternatively, if you want to permanently restructure a set of ‘foreign’
-files so that they match the GNAT rules, and do the remaining development
-using the GNAT structure, you can simply use @code{gnatchop} once, generate the
-new set of files and work with them from that point on.
+Alternatively, if you want to permanently restructure a set of
+‘foreign’ files so that they match the GNAT rules, and do the
+remaining development using the GNAT structure, you can simply use
+@code{gnatchop} once, generate the new set of files containing only one
+unit per file, and work with them from that point on.
Note that if your file containing multiple units starts with a byte order
-mark (BOM) specifying UTF-8 encoding, then the files generated by gnatchop
-will each start with a copy of this BOM, meaning that they can be compiled
-automatically in UTF-8 mode without needing to specify an explicit encoding.
+mark (BOM) specifying UTF-8 encoding, each file generated by gnatchop
+will start with a copy of this BOM, meaning that they can be compiled
+automatically in UTF-8 mode without you needing to specify an explicit encoding.
@node Operating gnatchop in Compilation Mode,Command Line for gnatchop,Handling Files with Multiple Units,Renaming Files with gnatchop
@anchor{gnat_ugn/the_gnat_compilation_model id24}@anchor{58}@anchor{gnat_ugn/the_gnat_compilation_model operating-gnatchop-in-compilation-mode}@anchor{59}
@@ -2455,27 +2459,27 @@ automatically in UTF-8 mode without needing to specify an explicit encoding.
The basic function of @code{gnatchop} is to take a file with multiple units
-and split it into separate files. The boundary between files is reasonably
+and split it into separate files. The boundary between units is reasonably
clear, except for the issue of comments and pragmas. In default mode, the
rule is that any pragmas between units belong to the previous unit, except
that configuration pragmas always belong to the following unit. Any comments
belong to the following unit. These rules
almost always result in the right choice of
-the split point without needing to mark it explicitly and most users will
-find this default to be what they want. In this default mode it is incorrect to
+the split point without you needing to mark it explicitly and you’ll likely
+find this default to be what you want. In this default mode, you may not
submit a file containing only configuration pragmas, or one that ends in
configuration pragmas, to @code{gnatchop}.
-However, using a special option to activate ‘compilation mode’,
+However, using a special switch to activate ‘compilation mode’,
@code{gnatchop}
can perform another function, which is to provide exactly the semantics
-required by the RM for handling of configuration pragmas in a compilation.
-In the absence of configuration pragmas (at the main file level), this
-option has no effect, but it causes such configuration pragmas to be handled
-in a quite different manner.
+required by the RM for the handling of configuration pragmas in a compilation.
+In the absence of configuration pragmas at the main file level, this
+switch has no effect, but it causes such configuration pragmas to be handled
+in a very different manner.
-First, in compilation mode, if @code{gnatchop} is given a file that consists of
-only configuration pragmas, then this file is appended to the
+First, in compilation mode, if you give @code{gnatchop} a file that consists of
+only configuration pragmas, it appends this file to the
@code{gnat.adc} file in the current directory. This behavior provides
the required behavior described in the RM for the actions to be taken
on submitting such a file to the compiler, namely that these pragmas
@@ -2485,14 +2489,13 @@ environment. Using GNAT, the current directory, possibly containing a
of a compilation environment. For more information on the
@code{gnat.adc} file, see @ref{3f,,Handling of Configuration Pragmas}.
-Second, in compilation mode, if @code{gnatchop}
-is given a file that starts with
-configuration pragmas, and contains one or more units, then these
-configuration pragmas are prepended to each of the chopped files. This
-behavior provides the required behavior described in the RM for the
-actions to be taken on compiling such a file, namely that the pragmas
-apply to all units in the compilation, but not to subsequently compiled
-units.
+Second, in compilation mode, if you give @code{gnatchop} a file that
+starts with configuration pragmas and contains one or more units, then
+configuration pragmas are prepended to each of the chopped
+files. This behavior provides the required behavior described in the
+RM for the actions to be taken on compiling such a file, namely that
+the pragmas apply to all units in the compilation, but not to
+subsequently compiled units.
Finally, if configuration pragmas appear between units, they are appended
to the previous unit. This results in the previous unit being illegal,
@@ -2501,12 +2504,12 @@ a unit. This provides the required RM behavior that forbids configuration
pragmas other than those preceding the first compilation unit of a
compilation.
-For most purposes, @code{gnatchop} will be used in default mode. The
-compilation mode described above is used only if you need exactly
-accurate behavior with respect to compilations, and you have files
+For most purposes, you will use @code{gnatchop} in default mode. You only
+use the compilation mode described above if you need precisely
+accurate behavior with respect to compilations and you have files
that contain multiple units and configuration pragmas. In this
-circumstance the use of @code{gnatchop} with the compilation mode
-switch provides the required behavior, and is for example the mode
+circumstance, the use of @code{gnatchop} with the compilation mode
+switch provides the required behavior. This is the mode
in which GNAT processes the ACVC tests.
@node Command Line for gnatchop,Switches for gnatchop,Operating gnatchop in Compilation Mode,Renaming Files with gnatchop
@@ -2514,7 +2517,7 @@ in which GNAT processes the ACVC tests.
@subsubsection Command Line for @code{gnatchop}
-The @code{gnatchop} command has the form:
+You call @code{gnatchop} as follows:
@example
$ gnatchop switches file_name [file_name ...]
@@ -2530,7 +2533,7 @@ When run in default mode, @code{gnatchop} generates one output file in
the current directory for each unit in each of the files.
@code{directory}, if specified, gives the name of the directory to which
-the output files will be written. If it is not specified, all files are
+the output files will be written. If you don’t specify it, all files are
written to the current directory.
For example, given a
@@ -2555,12 +2558,12 @@ $ gnatchop hellofiles
generates two files in the current directory, one called
@code{hello.ads} containing the single line that is the procedure spec,
and the other called @code{hello.adb} containing the remaining text. The
-original file is not affected. The generated files can be compiled in
+original file is not affected. You can compile these generated files in
the normal manner.
-When gnatchop is invoked on a file that is empty or that contains only empty
-lines and/or comments, gnatchop will not fail, but will not produce any
-new sources.
+When you invoke @code{gnatchop} on a file that is empty or contains only
+empty lines and/or comments, @code{gnatchop} will complete normally, but
+won’t produce any new file.
For example, given a
file called @code{toto.txt} containing
@@ -2597,7 +2600,7 @@ no source files written
@item @code{--version}
-Display Copyright and version, then exit disregarding all other options.
+Display copyright and version, then exit, disregarding all other options.
@end table
@geindex --help (gnatchop)
@@ -2607,7 +2610,7 @@ Display Copyright and version, then exit disregarding all other options.
@item @code{--help}
-If @code{--version} was not used, display usage, then exit disregarding
+If @code{--version} is not present, display usage, then exit, disregarding
all other options.
@end table
@@ -2619,14 +2622,14 @@ all other options.
@item @code{-c}
Causes @code{gnatchop} to operate in compilation mode, in which
-configuration pragmas are handled according to strict RM rules. See
+configuration pragmas are handled according to strict RM rules. See the
previous section for a full description of this mode.
@item @code{-gnat`xxx'}
-This passes the given @code{-gnat`xxx'} switch to @code{gnat} which is
+This passes the given @code{-gnat`xxx'} switch to @code{gcc} which is
used to parse the given file. Not all `xxx' options make sense,
-but for example, the use of @code{-gnati2} allows @code{gnatchop} to
+but, for example, the use of @code{-gnati2} allows @code{gnatchop} to
process a source file that uses Latin-2 coding for identifiers.
@item @code{-h}
@@ -2637,23 +2640,19 @@ output file showing usage information.
@geindex -k (gnatchop)
+@code{-k`mm'}
-@table @asis
-
-@item @code{-k`mm'}
+@quotation
-Limit generated file names to the specified number @code{mm}
-of characters.
-This is useful if the
-resulting set of files is required to be interoperable with systems
-which limit the length of file names.
-No space is allowed between the @code{-k} and the numeric value. The numeric
-value may be omitted in which case a default of @code{-k8},
-suitable for use
-with DOS-like file systems, is used. If no @code{-k} switch
-is present then
+Limit generated file names to the specified number @code{mm} of
+characters. This is useful if the resulting set of files is
+required to be interoperable with systems which limit the length of
+file names. You may not place any space between the @code{-k}
+and the numeric value. You can omit the numeric value, in which case
+@code{gnatchop} will use a default of @code{-k8}, suitable for use
+with DOS-like file systems. If you don’t specify a @code{-k} switch,
there is no limit on the length of file names.
-@end table
+@end quotation
@geindex -p (gnatchop)
@@ -2663,7 +2662,7 @@ there is no limit on the length of file names.
@item @code{-p}
Causes the file modification time stamp of the input file to be
-preserved and used for the time stamp of the output file(s). This may be
+preserved and used for the time stamp of the output file(s). You may find this
useful for preserving coherency of time stamps in an environment where
@code{gnatchop} is used as part of a standard build process.
@end table
@@ -2689,10 +2688,10 @@ files to be suppressed. Warnings and error messages are unaffected.
@item @code{-r}
Generate @code{Source_Reference} pragmas. Use this switch if the output
-files are regarded as temporary and development is to be done in terms
+files are regarded as temporary and development is to be done from
of the original unchopped file. This switch causes
@code{Source_Reference} pragmas to be inserted into each of the
-generated files to refers back to the original file name and line number.
+generated files to refer back to the original file name and line number.
The result is that all error messages refer back to the original
unchopped file.
In addition, the debugging information placed into the object file (when
@@ -2703,8 +2702,8 @@ debuggers will give information in terms of the original unchopped file.
If the original file to be chopped itself contains
a @code{Source_Reference}
-pragma referencing a third file, then gnatchop respects
-this pragma, and the generated @code{Source_Reference} pragmas
+pragma referencing a third file, @code{gnatchop} respects these
+pragmas and the generated @code{Source_Reference} pragmas
in the chopped file refer to the original file, with appropriate
line numbers. This is particularly useful when @code{gnatchop}
is used in conjunction with @code{gnatprep} to compile files that
@@ -2718,9 +2717,9 @@ contain preprocessing statements and multiple units.
@item @code{-v}
-Causes @code{gnatchop} to operate in verbose mode. The version
-number and copyright notice are output, as well as exact copies of
-the gnat1 commands spawned to obtain the chop control information.
+Causes @code{gnatchop} to operate in verbose mode. It outputs the
+version number and copyright notice as well as exact copies of the
+commands spawned to obtain the information needed to control chopping.
@end table
@geindex -w (gnatchop)
@@ -2730,11 +2729,12 @@ the gnat1 commands spawned to obtain the chop control information.
@item @code{-w}
-Overwrite existing file names. Normally @code{gnatchop} regards it as a
-fatal error if there is already a file with the same name as a
-file it would otherwise output, in other words if the files to be
+Overwrite existing file names. Normally, @code{gnatchop} treats it as a
+fatal error if there’s already a file with the same name as a
+file it would otherwise output. This can happen either if you’ve previously
+chopped that file or if the files to be
chopped contain duplicated units. This switch bypasses this
-check, and causes all but the last instance of such duplicated
+check and causes all but the last instance of such duplicated
units to be skipped.
@end table
@@ -2746,7 +2746,8 @@ units to be skipped.
@item @code{--GCC=`xxxx'}
Specify the path of the GNAT parser to be used. When this switch is used,
-no attempt is made to add the prefix to the GNAT parser executable.
+@code{gnatchop} makes no attempt to add a prefix to the GNAT parser executable,
+so it must include the full pathname.
@end table
@node Examples of gnatchop Usage,,Switches for gnatchop,Renaming Files with gnatchop
@@ -2758,7 +2759,7 @@ no attempt is made to add the prefix to the GNAT parser executable.
$ gnatchop -w hello_s.ada prerelease/files
@end example
-Chops the source file @code{hello_s.ada}. The output files will be
+Chops the source file @code{hello_s.ada}. The output files are
placed in the directory @code{prerelease/files},
overwriting any
files with matching names in that directory (no files in the current
@@ -2773,22 +2774,22 @@ into the current directory. One
useful application of @code{gnatchop} is in sending sets of sources
around, for example in email messages. The required sources are simply
concatenated (for example, using a Unix @code{cat}
-command), and then
+command) and
@code{gnatchop} is used at the other end to reconstitute the original
-file names.
+files.
@example
$ gnatchop file1 file2 file3 direc
@end example
-Chops all units in files @code{file1}, @code{file2}, @code{file3}, placing
-the resulting files in the directory @code{direc}. Note that if any units
-occur more than once anywhere within this set of files, an error message
-is generated, and no files are written. To override this check, use the
-@code{-w} switch,
-in which case the last occurrence in the last file will
-be the one that is output, and earlier duplicate occurrences for a given
-unit will be skipped.
+Chops all units in files @code{file1}, @code{file2}, @code{file3},
+placing the resulting files in the directory @code{direc}. Note that
+if any units occur more than once anywhere within this set of files,
+@code{gnatchop} generates an error message, and doesn’t write any
+files. To override this check, use the @code{-w} switch, in which
+case the last occurrence in the last file will be the one that is
+output and @code{gnatchop} will skip earlier duplicate occurrences for
+the same unit.
@node Configuration Pragmas,Generating Object Files,File Naming Topics and Utilities,The GNAT Compilation Model
@anchor{gnat_ugn/the_gnat_compilation_model configuration-pragmas}@anchor{25}@anchor{gnat_ugn/the_gnat_compilation_model id28}@anchor{60}
@@ -2800,8 +2801,8 @@ unit will be skipped.
@geindex Pragmas
@geindex configuration
-Configuration pragmas include those pragmas described as
-such in the Ada Reference Manual, as well as
+Configuration pragmas supported by GNAT consist of those pragmas described as
+such in the Ada Reference Manual and the
implementation-dependent pragmas that are configuration pragmas.
See the @code{Implementation_Defined_Pragmas} chapter in the
@cite{GNAT_Reference_Manual} for details on these
@@ -2898,15 +2899,15 @@ Wide_Character_Encoding
@subsection Handling of Configuration Pragmas
-Configuration pragmas may either appear at the start of a compilation
-unit, or they can appear in a configuration pragma file to apply to
+You can place configuration pragmas either appear at the start of a compilation
+unit or in a configuration pragma file that applies to
all compilations performed in a given compilation environment.
-GNAT also provides the @code{gnatchop} utility to provide an automatic
-way to handle configuration pragmas following the semantics for
-compilations (that is, files with multiple units), described in the RM.
+GNAT includes the @code{gnatchop} utility to provide an automatic
+way to handle configuration pragmas that follows the semantics for
+compilations (that is, files with multiple units) described in the RM.
See @ref{59,,Operating gnatchop in Compilation Mode} for details.
-However, for most purposes, it will be more convenient to edit the
+However, for most purposes, you will find it more convenient to edit the
@code{gnat.adc} file that contains configuration pragmas directly,
as described in the following section.
@@ -2918,21 +2919,22 @@ Restrictions that require partition-wide consistency (like
@code{No_Tasking}) are
recognized wherever they appear
and can be freely inherited, e.g. from a `with'ed unit to the `with'ing
-unit. This makes sense since the binder will in any case insist on seeing
-consistent use, so any unit not conforming to any restrictions that are
-anywhere in the partition will be rejected, and you might as well find
-that out at compile time rather than at bind time.
+unit. This makes sense since the binder will always insist on seeing
+consistent us, so any unit not conforming to any restrictions
+anywhere in the partition will be rejected and it’s better for you to find
+that out at compile time rather than bind time.
For restrictions that do not require partition-wide consistency, e.g.
-SPARK or No_Implementation_Attributes, in general the restriction applies
-only to the unit in which the pragma appears, and not to any other units.
+@code{SPARK} or @code{No_Implementation_Attributes}, the restriction
+normally applies only to the unit in which the pragma appears, and not
+to any other units.
-The exception is No_Elaboration_Code which always applies to the entire
-object file from a compilation, i.e. to the body, spec, and all subunits.
-This restriction can be specified in a configuration pragma file, or it
-can be on the body and/or the spec (in either case it applies to all the
-relevant units). It can appear on a subunit only if it has previously
-appeared in the body of spec.
+The exception is @code{No_Elaboration_Code}, which always applies to the
+entire object file from a compilation, i.e. to the body, spec, and all
+subunits. You can apply this restriction in a configuration pragma
+file or you can ace it in the body and/or the spec (in either case it
+applies to all the relevant units). You can place it on a subunit only if
+you have previously placed it in the body of spec.
@node The Configuration Pragmas Files,,Handling of Configuration Pragmas,Configuration Pragmas
@anchor{gnat_ugn/the_gnat_compilation_model id30}@anchor{62}@anchor{gnat_ugn/the_gnat_compilation_model the-configuration-pragmas-files}@anchor{63}
@@ -2941,33 +2943,33 @@ appeared in the body of spec.
@geindex gnat.adc
-In GNAT a compilation environment is defined by the current
-directory at the time that a compile command is given. This current
-directory is searched for a file whose name is @code{gnat.adc}. If
-this file is present, it is expected to contain one or more
-configuration pragmas that will be applied to the current compilation.
-However, if the switch @code{-gnatA} is used, @code{gnat.adc} is not
-considered. When taken into account, @code{gnat.adc} is added to the
-dependencies, so that if @code{gnat.adc} is modified later, an invocation of
-@code{gnatmake} will recompile the source.
-
-Configuration pragmas may be entered into the @code{gnat.adc} file
-either by running @code{gnatchop} on a source file that consists only of
-configuration pragmas, or more conveniently by direct editing of the
+In GNAT, a compilation environment is defined by the current directory
+at the time that a compile command is given. This current directory is
+searched for a file whose name is @code{gnat.adc}. If this file is
+present, it is expected to contain one or more configuration pragmas
+that will be applied to the current compilation. However, if you
+specify the switch @code{-gnatA}, GNAT ignores
+@code{gnat.adc}. When used, GNAT adds @code{gnat.adc} to the
+dependencies so that if @code{gnat.adc} is modified later, the source
+will be recompiled on a future invocation of @code{gnatmake}.
+
+You can add
+configuration pragmas into the @code{gnat.adc} file
+either by running @code{gnatchop} on a source file consisting only of
+configuration pragmas or, more conveniently, by directly editing the
@code{gnat.adc} file, which is a standard format source file.
-Besides @code{gnat.adc}, additional files containing configuration
-pragmas may be applied to the current compilation using the switch
-@code{-gnatec=`path'} where @code{path} must designate an existing file that
-contains only configuration pragmas. These configuration pragmas are
-in addition to those found in @code{gnat.adc} (provided @code{gnat.adc}
-is present and switch @code{-gnatA} is not used).
-
-It is allowable to specify several switches @code{-gnatec=}, all of which
-will be taken into account.
-
-Files containing configuration pragmas specified with switches
-@code{-gnatec=} are added to the dependencies, unless they are
+Besides @code{gnat.adc}, you may apply additional files containing
+configuration pragmas to the current compilation using the
+@code{-gnatec=`path'} switch, where @code{path} must designate an
+existing file that contains only configuration pragmas. These
+configuration pragmas are in addition to those found in
+@code{gnat.adc} (provided @code{gnat.adc} is present and you do not
+use switch @code{-gnatA}).
+You can specify multiple @code{-gnatec=} switches.
+
+GNAT will add files containing configuration pragmas specified with switches
+@code{-gnatec=} to the dependencies, unless they are
temporary files. A file is considered temporary if its name ends in
@code{.tmp} or @code{.TMP}. Certain tools follow this naming
convention because they pass information to @code{gcc} via
@@ -2975,11 +2977,11 @@ temporary files that are immediately deleted; it doesn’t make sense to
depend on a file that no longer exists. Such tools include
@code{gprbuild}, @code{gnatmake}, and @code{gnatcheck}.
-By default, configuration pragma files are stored by their absolute paths in
-ALI files. You can use the @code{-gnateb} switch in order to store them by
-their basename instead.
+By default, configuration pragma files are stored by their absolute
+paths in ALI files. You can use the @code{-gnateb} switch to
+request they be stored instead by just their basename.
-If you are using project file, a separate mechanism is provided using
+If you are using project file, they provide a separate mechanism using
project attributes.
@c --Comment
@@ -2990,9 +2992,9 @@ project attributes.
@section Generating Object Files
-An Ada program consists of a set of source files, and the first step in
-compiling the program is to generate the corresponding object files.
-These are generated by compiling a subset of these source files.
+An Ada program consists of a set of source files and the first step in
+compiling the program is generating the corresponding object files.
+You generate these by compiling a subset of these source files.
The files you need to compile are the following:
@@ -3003,15 +3005,16 @@ If a package spec has no body, compile the package spec to produce the
object file for the package.
@item
-If a package has both a spec and a body, compile the body to produce the
-object file for the package. The source file for the package spec need
-not be compiled in this case because there is only one object file, which
-contains the code for both the spec and body of the package.
+If a package has both a spec and a body, compile the body to produce
+the object file for the package. You need not compile the source
+file for the package spec in this case because there’s only one
+object file, which contains the code for both the spec and body of
+the package.
@item
-For a subprogram, compile the subprogram body to produce the object file
-for the subprogram. The spec, if one is present, is as usual in a
-separate file, and need not be compiled.
+For a subprogram, compile the subprogram body to produce the object
+file for the subprogram. You need not compile the spec, if such a file is
+present.
@end itemize
@geindex Subunits
@@ -3020,35 +3023,37 @@ separate file, and need not be compiled.
@itemize *
@item
-In the case of subunits, only compile the parent unit. A single object
-file is generated for the entire subunit tree, which includes all the
-subunits.
+In the case of subunits, only compile the parent unit. GNAT
+generates a single object file for the entire subunit tree, which
+includes all the subunits.
@item
-Compile child units independently of their parent units
-(though, of course, the spec of all the ancestor unit must be present in order
+Compile child units independently of their parent units (though, of
+course, the spec of all the ancestor unit must be present in order
to compile a child unit).
@geindex Generics
@item
-Compile generic units in the same manner as any other units. The object
-files in this case are small dummy files that contain at most the
-flag used for elaboration checking. This is because GNAT always handles generic
-instantiation by means of macro expansion. However, it is still necessary to
-compile generic units, for dependency checking and elaboration purposes.
+Compile generic units in the same manner as any other units. The
+object files in this case are small dummy files that contain, at
+most, the flag used for elaboration checking. This is because GNAT
+always handles generic instantiation by means of macro
+expansion. However, you still must compile generic units
+for dependency checking and elaboration purposes.
@end itemize
The preceding rules describe the set of files that must be compiled to
-generate the object files for a program. Each object file has the same
+generate all the object files for a program. See the following section on dependencies for more details on computing that set of files.
+Each object file has the same
name as the corresponding source file, except that the extension is
-@code{.o} as usual.
+@code{.o}, as usual.
You may wish to compile other files for the purpose of checking their
syntactic and semantic correctness. For example, in the case where a
package has a separate spec and body, you would not normally compile the
spec. However, it is convenient in practice to compile the spec to make
-sure it is error-free before compiling clients of this spec, because such
+sure it is error-free before compiling clients of this spec because such
compilations will fail if there is an error in the spec.
GNAT provides an option for compiling such files purely for the
@@ -3061,13 +3066,12 @@ checking mode, use the @code{-gnatc} switch.
@section Source Dependencies
-A given object file clearly depends on the source file which is compiled
-to produce it. Here we are using “depends” in the sense of a typical
-@code{make} utility; in other words, an object file depends on a source
-file if changes to the source file require the object file to be
-recompiled.
-In addition to this basic dependency, a given object may depend on
-additional source files as follows:
+Each object file obviously depends on at least the source file which
+is compiled to produce it. Here we are using “depends” in the sense of
+a typical @code{make} utility; in other words, an object file depends on
+a source file if changes to the source file require the object file to
+be recompiled. In addition to this basic dependency, a given object
+may depend on additional source files as follows:
@itemize *
@@ -3076,7 +3080,7 @@ additional source files as follows:
If a file being compiled `with's a unit @code{X}, the object file
depends on the file containing the spec of unit @code{X}. This includes
files that are `with'ed implicitly either because they are parents
-of `with'ed child units or they are run-time units required by the
+of `with'ed child units or are run-time units required by the
language constructs used in a particular unit.
@item
@@ -3099,11 +3103,11 @@ well as the spec file.
@item
If a file being compiled contains a call to a subprogram for which
-pragma @code{Inline} applies and inlining is activated with the
+pragma @code{Inline} applies and you have activated inlining with the
@code{-gnatn} switch, the object file depends on the file containing the
body of this subprogram as well as on the file containing the spec. Note
that for inlining to actually occur as a result of the use of this switch,
-it is necessary to compile in optimizing mode.
+you must compile in optimizing mode.
@geindex -gnatN switch
@@ -3112,9 +3116,9 @@ that is performed by the front end of the compiler. This inlining does
not require that the code generation be optimized. Like @code{-gnatn},
the use of this switch generates additional dependencies.
-When using a gcc-based back end, then the use of
-@code{-gnatN} is deprecated, and the use of @code{-gnatn} is preferred.
-Historically front end inlining was more extensive than the gcc back end
+When using a @code{gcc} or LLVM based back end, the use of
+@code{-gnatN} is deprecated and the use of @code{-gnatn} is preferred.
+Historically front end inlining was more extensive than back end
inlining, but that is no longer the case.
@item
@@ -3127,12 +3131,13 @@ affects the compilation of @code{O}.
The object file for a parent unit depends on all its subunit body files.
@item
-The previous two rules meant that for purposes of computing dependencies and
-recompilation, a body and all its subunits are treated as an indivisible whole.
+The previous two rules means that, for purposes of computing
+dependencies and recompilation, a body and all its subunits are
+treated as an indivisible whole.
These rules are applied transitively: if unit @code{A} `with's
unit @code{B}, whose elaboration calls an inlined procedure in package
-@code{C}, the object file for unit @code{A} will depend on the body of
+@code{C}, the object file for unit @code{A} depends on the body of
@code{C}, in file @code{c.adb}.
The set of dependent files described by these rules includes all the
@@ -3141,13 +3146,13 @@ Ada language standard. However, it is a superset of what the
standard describes, because it includes generic, inline, and subunit
dependencies.
-An object file must be recreated by recompiling the corresponding source
-file if any of the source files on which it depends are modified. For
-example, if the @code{make} utility is used to control compilation,
-the rule for an Ada object file must mention all the source files on
-which the object file depends, according to the above definition.
-The determination of the necessary
-recompilations is done automatically when one uses @code{gnatmake}.
+An object file must be recreated by recompiling the corresponding
+source file if any of the source files on which it depends are
+modified. For example, if the @code{make} utility is used to control
+compilation, the rule for an Ada object file must mention all the
+source files on which the object file depends, according to the
+above definition. Invoking @code{gnatmake} will cause it to determine
+the necessary recompilations.
@end itemize
@node The Ada Library Information Files,Binding an Ada Program,Source Dependencies,The GNAT Compilation Model
@@ -3160,11 +3165,11 @@ recompilations is done automatically when one uses @code{gnatmake}.
@geindex ALI files
Each compilation actually generates two output files. The first of these
-is the normal object file that has a @code{.o} extension. The second is a
+is the actual object file that has a @code{.o} extension. The second is a
text file containing full dependency information. It has the same
name as the source file, but an @code{.ali} extension.
This file is known as the Ada Library Information (@code{ALI}) file.
-The following information is contained in the @code{ALI} file.
+The following information is contained in that file:
@itemize *
@@ -3178,15 +3183,16 @@ Main program information (including priority and time slice settings,
as well as the wide character encoding used during compilation).
@item
-List of arguments used in the @code{gcc} command for the compilation
+List of arguments used in the compilation command
@item
-Attributes of the unit, including configuration pragmas used, an indication
-of whether the compilation was successful, exception model used etc.
+Attributes of the unit, including the configuration pragmas used, an
+indication of whether the compilation was successful, and the exception
+model used.
@item
-A list of relevant restrictions applying to the unit (used for consistency)
-checking.
+A list of relevant restrictions applying to the unit (used for consistency
+checking).
@item
Categorization information (e.g., use of pragma @code{Pure}).
@@ -3205,8 +3211,8 @@ attributes in the unit.
@item
Dependency information. This is a list of files, together with
time stamp and checksum information. These are files on which
-the unit depends in the sense that recompilation is required
-if any of these units are modified.
+the unit depends in the sense that the modification of any of
+these units requires the recompilation of the unit in question.
@item
Cross-reference data. Contains information on all entities referenced
@@ -3224,7 +3230,7 @@ see the source of the body of unit @code{Lib.Writ}, contained in file
When using languages such as C and C++, once the source files have been
compiled the only remaining step in building an executable program
-is linking the object modules together. This means that it is possible to
+is linking the object modules together. This means that you can
link an inconsistent version of a program, in which two units have
included different versions of the same header.
@@ -3235,13 +3241,13 @@ These rules are enforced by the GNAT binder, which also determines an
elaboration order consistent with the Ada rules.
The GNAT binder is run after all the object files for a program have
-been created. It is given the name of the main program unit, and from
-this it determines the set of units required by the program, by reading the
+been created. It is given the name of the main program unit and from
+this determines the set of units required by the program by reading the
corresponding ALI files. It generates error messages if the program is
inconsistent or if no valid order of elaboration exists.
-If no errors are detected, the binder produces a main program, in Ada by
-default, that contains calls to the elaboration procedures of those
+If no errors are detected, the binder produces a main program in Ada
+that contains calls to the elaboration procedures of those
compilation unit that require them, followed by
a call to the main program. This Ada program is compiled to generate the
object file for the main program. The name of
@@ -3258,12 +3264,12 @@ object files for the Ada units of the program.
@section GNAT and Libraries
-@geindex Library building and using
+@geindex Library building and referencing
-This section describes how to build and use libraries with GNAT, and also shows
+This section describes how to build and use libraries with GNAT and
how to recompile the GNAT run-time library. You should be familiar with the
Project Manager facility (see the `GNAT_Project_Manager' chapter of the
-`GPRbuild User’s Guide') before reading this chapter.
+@cite{GPRbuild User’s Guide}) before reading this chapter.
@menu
* Introduction to Libraries in GNAT::
@@ -3279,20 +3285,20 @@ Project Manager facility (see the `GNAT_Project_Manager' chapter of the
A library is, conceptually, a collection of objects which does not have its
-own main thread of execution, but rather provides certain services to the
+own main thread of execution but instead provides certain services to the
applications that use it. A library can be either statically linked with the
application, in which case its code is directly included in the application,
or, on platforms that support it, be dynamically linked, in which case
its code is shared by all applications making use of this library.
GNAT supports both types of libraries.
-In the static case, the compiled code can be provided in different ways. The
-simplest approach is to provide directly the set of objects resulting from
+In the static case, you can provide the compiled code in different ways. The
+simplest approach is to directly provide the set of objects resulting from
compilation of the library source files. Alternatively, you can group the
objects into an archive using whatever commands are provided by the operating
-system. For the latter case, the objects are grouped into a shared library.
+system.
-In the GNAT environment, a library has three types of components:
+In the GNAT environment, a library has these components:
@itemize *
@@ -3304,12 +3310,12 @@ Source files,
@code{ALI} files (see @ref{28,,The Ada Library Information Files}), and
@item
-Object files, an archive or a shared library.
+Object files, an archive, or a shared library.
@end itemize
A GNAT library may expose all its source files, which is useful for
documentation purposes. Alternatively, it may expose only the units needed by
-an external user to make use of the library. That is to say, the specs
+an external user to make use of the library, in other words, the specs
reflecting the library services along with all the units needed to compile
those specs, which can include generic bodies or any body implementing an
inlined routine. In the case of `stand-alone libraries' those exposed
@@ -3343,12 +3349,12 @@ using the library.
The easiest way to build a library is to use the Project Manager,
which supports a special type of project called a `Library Project'
(see the `Library Projects' section in the `GNAT Project Manager'
-chapter of the `GPRbuild User’s Guide').
+chapter of the @cite{GPRbuild User’s Guide}).
-A project is considered a library project, when two project-level attributes
-are defined in it: @code{Library_Name} and @code{Library_Dir}. In order to
-control different aspects of library configuration, additional optional
-project-level attributes can be specified:
+A project is considered a library project when two project-level
+attributes are defined in it: @code{Library_Name} and @code{Library_Dir}. In
+order to control different aspects of library configuration, you can
+specify additional optional project-level attributes:
@itemize *
@@ -3368,7 +3374,7 @@ This attribute controls whether the library is to be static or dynamic
@item @code{Library_Version}
-This attribute specifies the library version; this value is used
+This attribute specifies the library version. Its value is used
during dynamic linking of shared libraries to determine if the currently
installed versions of the binaries are compatible.
@end table
@@ -3383,18 +3389,18 @@ installed versions of the binaries are compatible.
@item @code{Library_GCC}
These attributes specify additional low-level options to be used during
-library generation, and redefine the actual application used to generate
+library generation and the commands used to generate the
library.
@end table
@end itemize
-The GNAT Project Manager takes full care of the library maintenance task,
+The GNAT Project Manager takes complete care of the library maintenance task,
including recompilation of the source files for which objects do not exist
or are not up to date, assembly of the library archive, and installation of
the library (i.e., copying associated source, object and @code{ALI} files
to the specified location).
-Here is a simple library project file:
+Here’s a simple library project file:
@example
project My_Lib is
@@ -3412,22 +3418,23 @@ and the compilation command to build and install the library:
$ gnatmake -Pmy_lib
@end example
-It is not entirely trivial to perform manually all the steps required to
-produce a library. We recommend that you use the GNAT Project Manager
-for this task. In special cases where this is not desired, the necessary
-steps are discussed below.
+It’s complex to manually perform all the steps required to
+produce a library, so we recommend you use the GNAT Project Manager
+for this task. In case this is not desired, we discuss the necessary
+steps below.
-There are various possibilities for compiling the units that make up the
-library: for example with a Makefile (@ref{70,,Using the GNU make Utility}) or
-with a conventional script. For simple libraries, it is also possible to create
-a dummy main program which depends upon all the packages that comprise the
-interface of the library. This dummy main program can then be given to
-@code{gnatmake}, which will ensure that all necessary objects are built.
+There are various possibilities for compiling the units that make up
+the library: for example with a @code{Makefile}
+(@ref{70,,Using the GNU make Utility}) or with a conventional script. For
+simple libraries, you can also create a dummy main program
+that depends upon all the packages that comprise the interface of the
+library. You can then pass this dummy main program to @code{gnatmake},
+which will ensure all necessary objects are built.
-After this task is accomplished, you should follow the standard procedure
+After the above has been accomplished, you should follow the standard procedure
of the underlying operating system to produce the static or shared library.
-Here is an example of such a dummy program:
+Here’s an example of such a dummy program:
@example
with My_Lib.Service1;
@@ -3466,7 +3473,7 @@ $ chmod -w *.ali
Please note that the library must have a name of the form @code{lib`xxx'.a}
or @code{lib`xxx'.so} (or @code{lib`xxx'.dll} on Windows) in order to
-be accessed by the directive @code{-l`xxx'} at link time.
+be accessed by the @code{-l`xxx'} switch at link time.
@node Installing a library,Using a library,Building a library,General Ada Libraries
@anchor{gnat_ugn/the_gnat_compilation_model id39}@anchor{71}@anchor{gnat_ugn/the_gnat_compilation_model installing-a-library}@anchor{72}
@@ -3479,17 +3486,19 @@ be accessed by the directive @code{-l`xxx'} at link time.
If you use project files, library installation is part of the library build
process (see the `Installing a Library with Project Files' section of the
-`GNAT Project Manager' chapter of the `GPRbuild User’s Guide').
+`GNAT Project Manager' chapter of the @cite{GPRbuild User’s Guide}).
-When project files are not an option, it is also possible, but not recommended,
-to install the library so that the sources needed to use the library are on the
-Ada source path and the ALI files & libraries be on the Ada Object path (see
-@ref{73,,Search Paths and the Run-Time Library (RTL)}). Alternatively, the system
-administrator can place general-purpose libraries in the default compiler
-paths, by specifying the libraries’ location in the configuration files
-@code{ada_source_path} and @code{ada_object_path}. These configuration files
-must be located in the GNAT installation tree at the same place as the gcc spec
-file. The location of the gcc spec file can be determined as follows:
+When you’re not able to use project files for some reason, you can
+also install the library so that the sources needed to use the library
+are on the Ada source path and the ALI files & libraries be on the Ada
+Object path (see @ref{73,,Search Paths and the Run-Time Library (RTL)}),
+but we don’t recommend doing this. Alternatively, the system
+administrator can place general-purpose libraries in the default
+compiler paths, by specifying the libraries’ location in the
+configuration files @code{ada_source_path} and
+@code{ada_object_path}. These configuration files must be located in
+the GNAT installation tree at the same place as the @code{gcc} spec
+file. The location of the @code{gcc} spec file can be determined as follows:
@example
$ gcc -v
@@ -3504,7 +3513,7 @@ are located.
The files @code{ada_source_path} and @code{ada_object_path} might not be
present in a
-GNAT installation, in which case, GNAT will look for its run-time library in
+GNAT installation, in which case, GNAT looks for its run-time library in
the directories @code{adainclude} (for the sources) and @code{adalib} (for the
objects and @code{ALI} files). When the files exist, the compiler does not
look in @code{adainclude} and @code{adalib}, and thus the
@@ -3514,16 +3523,16 @@ be @code{adainclude}). In the same way, the @code{ada_object_path} file must
contain the location for the GNAT run-time objects (which can simply
be @code{adalib}).
-You can also specify a new default path to the run-time library at compilation
-time with the switch @code{--RTS=rts-path}. You can thus choose / change
-the run-time library you want your program to be compiled with. This switch is
-recognized by @code{gcc}, @code{gnatmake}, @code{gnatbind}, @code{gnatls}, and all
-project aware tools.
+You can also specify a new default path to the run-time library at
+compilation time with the @code{--RTS=rts-path} switch. You can
+thus choose the run-time library you want your program to be
+compiled with. This switch is recognized by @code{gcc}, @code{gnatmake},
+@code{gnatbind}, @code{gnatls}, and all project aware tools.
-It is possible to install a library before or after the standard GNAT
-library, by reordering the lines in the configuration files. In general, a
-library must be installed before the GNAT library if it redefines
-any part of it.
+You can install a library before or after the standard GNAT library by
+selecting the ordering the lines in the configuration files. In
+general, a library must be installed before the GNAT library if it
+redefines any part of it.
@node Using a library,,Installing a library,General Ada Libraries
@anchor{gnat_ugn/the_gnat_compilation_model id40}@anchor{74}@anchor{gnat_ugn/the_gnat_compilation_model using-a-library}@anchor{75}
@@ -3532,7 +3541,7 @@ any part of it.
Once again, the project facility greatly simplifies the use of
libraries. In this context, using a library is just a matter of adding a
-`with' clause in the user project. For instance, to make use of the
+`with' clause in your project. For example, to make use of the
library @code{My_Lib} shown in examples in earlier sections, you can
write:
@@ -3639,28 +3648,25 @@ install area.
@subsubsection Introduction to Stand-alone Libraries
-A Stand-alone Library (abbreviated ‘SAL’) is a library that contains the
-necessary code to
-elaborate the Ada units that are included in the library. In contrast with
-an ordinary library, which consists of all sources, objects and @code{ALI}
-files of the
-library, a SAL may specify a restricted subset of compilation units
-to serve as a library interface. In this case, the fully
-self-sufficient set of files will normally consist of an objects
-archive, the sources of interface units’ specs, and the @code{ALI}
-files of interface units.
-If an interface spec contains a generic unit or an inlined subprogram,
-the body’s
-source must also be provided; if the units that must be provided in the source
-form depend on other units, the source and @code{ALI} files of those must
-also be provided.
+A Stand-alone Library (abbreviated ‘SAL’) is a library that contains
+the necessary code to elaborate the Ada units that are included in the
+library. In contrast with an ordinary library, which consists of all
+sources, objects and @code{ALI} files of the library, a SAL may
+specify a restricted subset of compilation units to serve as a library
+interface. In this case, the fully self-sufficient set of files will
+normally consist of an objects archive, the sources of interface
+units’ specs, and the @code{ALI} files of interface units. If an
+interface spec contains a generic unit or an inlined subprogram, you
+must also provide the body’s source; if the units that must be
+provided in the source form depend on other units, you must also
+provide the source and @code{ALI} files of those units.
The main purpose of a SAL is to minimize the recompilation overhead of client
applications when a new version of the library is installed. Specifically,
-if the interface sources have not changed, client applications do not need to
+if the interface sources have not changed, client applications don’t need to
be recompiled. If, furthermore, a SAL is provided in the shared form and its
version, controlled by @code{Library_Version} attribute, is not changed,
-then the clients do not need to be relinked.
+the clients also do not need to be relinked.
SALs also allow the library providers to minimize the amount of library source
text exposed to the clients. Such ‘information hiding’ might be useful or
@@ -3676,12 +3682,12 @@ main routine is not written in Ada.
GNAT’s Project facility provides a simple way of building and installing
stand-alone libraries; see the `Stand-alone Library Projects' section
-in the `GNAT Project Manager' chapter of the `GPRbuild User’s Guide'.
+in the `GNAT Project Manager' chapter of the @cite{GPRbuild User’s Guide}.
To be a Stand-alone Library Project, in addition to the two attributes
that make a project a Library Project (@code{Library_Name} and
@code{Library_Dir}; see the `Library Projects' section in the
`GNAT Project Manager' chapter of the `GPRbuild User’s Guide'),
-the attribute @code{Library_Interface} must be defined. For example:
+you must define the attribute @code{Library_Interface}. For example:
@example
for Library_Dir use "lib_dir";
@@ -3693,7 +3699,7 @@ Attribute @code{Library_Interface} has a non-empty string list value,
each string in the list designating a unit contained in an immediate source
of the project file.
-When a Stand-alone Library is built, first the binder is invoked to build
+When a Stand-alone Library is built, the binder is first invoked to build
a package whose name depends on the library name
(@code{b~dummy.ads/b} in the example above).
This binder-generated package includes initialization and
@@ -3714,13 +3720,13 @@ the Library Directory. As a consequence, only the Interface Units may be
imported from Ada units outside of the library. If other units are imported,
the binding phase will fail.
-It is also possible to build an encapsulated library where not only
+You can also build an encapsulated library where not only
the code to elaborate and finalize the library is embedded but also
-ensuring that the library is linked only against static
-libraries. So an encapsulated library only depends on system
-libraries, all other code, including the GNAT runtime, is embedded. To
-build an encapsulated library the attribute
-@code{Library_Standalone} must be set to @code{encapsulated}:
+ensure that the library is linked only against static
+libraries. That means that an encapsulated library only depends on system
+libraries: all other code, including the GNAT runtime, is embedded. To
+build an encapsulated library you must set attribute
+@code{Library_Standalone} to @code{encapsulated}:
@example
for Library_Dir use "lib_dir";
@@ -3733,19 +3739,20 @@ for Library_Standalone use "encapsulated";
The default value for this attribute is @code{standard} in which case
a stand-alone library is built.
-The attribute @code{Library_Src_Dir} may be specified for a
-Stand-Alone Library. @code{Library_Src_Dir} is a simple attribute that has a
-single string value. Its value must be the path (absolute or relative to the
-project directory) of an existing directory. This directory cannot be the
-object directory or one of the source directories, but it can be the same as
-the library directory. The sources of the Interface
-Units of the library that are needed by an Ada client of the library will be
-copied to the designated directory, called the Interface Copy directory.
-These sources include the specs of the Interface Units, but they may also
-include bodies and subunits, when pragmas @code{Inline} or @code{Inline_Always}
-are used, or when there is a generic unit in the spec. Before the sources
-are copied to the Interface Copy directory, an attempt is made to delete all
-files in the Interface Copy directory.
+You may specify the attribute @code{Library_Src_Dir} for a Stand-Alone
+Library. @code{Library_Src_Dir} has a single string value. Its value must
+be the path (absolute or relative to the project directory) of an
+existing directory. This directory cannot be the object directory or
+one of the source directories, but it can be the same as the library
+directory. The sources of the Interface Units of the library that are
+needed by an Ada client of the library are copied to the designated
+directory, called the Interface Copy directory, when the library is
+built. These sources include the specs of the Interface Units, but
+they may also include bodies and subunits when pragmas @code{Inline} or
+@code{Inline_Always} are used or when there is a generic unit in the
+spec. Before the sources are copied to the Interface Copy directory,
+the building process makes an attempt to delete all files in the
+Interface Copy directory.
Building stand-alone libraries by hand is somewhat tedious, but for those
occasions when it is necessary here are the steps that you need to perform:
@@ -3775,10 +3782,10 @@ $ gcc -c b~int2.adb
@item
Link the dynamic library with all the necessary object files,
-indicating to the linker the names of the @code{init} (and possibly
+passing to the linker the names of the @code{init} (and possibly
@code{final}) procedures for automatic initialization (and finalization).
-The built library should be placed in a directory different from
-the object directory.
+You should place the built library in a different directory than
+the object files.
@item
Copy the @code{ALI} files of the interface to the library directory,
@@ -3796,14 +3803,14 @@ Using SALs is not different from using other libraries
@subsubsection Creating a Stand-alone Library to be used in a non-Ada context
-It is easy to adapt the SAL build procedure discussed above for use of a SAL in
-a non-Ada context.
+It’s easy for you to adapt the SAL build procedure discussed above for
+use of a SAL in a non-Ada context.
The only extra step required is to ensure that library interface subprograms
are compatible with the main program, by means of @code{pragma Export}
or @code{pragma Convention}.
-Here is an example of simple library interface for use with C main program:
+Here’s an example of simple library interface for use with C main program:
@example
package My_Package is
@@ -3817,7 +3824,7 @@ package My_Package is
end My_Package;
@end example
-On the foreign language side, you must provide a ‘foreign’ view of the
+On the C side, you must provide a ‘foreign’ view of the
library interface; remember that it should contain elaboration routines in
addition to interface subprograms.
@@ -3837,9 +3844,9 @@ extern void do_something_else (void);
@end example
Libraries built as explained above can be used from any program, provided
-that the elaboration procedures (named @code{mylibinit} in the previous
-example) are called before the library services are used. Any number of
-libraries can be used simultaneously, as long as the elaboration
+the elaboration procedures (named @code{mylibinit} in the previous
+example) are called before any library services are used. Any number of
+libraries can be called from a single executable as long as the elaboration
procedure of each library is called.
Below is an example of a C program that uses the @code{mylib} library.
@@ -3873,19 +3880,20 @@ after the finalization phase.
Information on limitations of binding Ada code in non-Ada contexts can be
found under @ref{7e,,Binding with Non-Ada Main Programs}.
-Note also that special care must be taken with multi-tasks
-applications. The initialization and finalization routines are not
-protected against concurrent access. If such requirement is needed it
-must be ensured at the application level using a specific operating
-system services like a mutex or a critical-section.
+Note also that you must take special care with multi-tasking
+applications. In that case, the initialization and finalization
+routines are not protected against concurrent access. If you need such
+requirement, you must ensure it at the application level
+using a specific operating system services like a mutex or a
+critical-section.
@node Restrictions in Stand-alone Libraries,,Creating a Stand-alone Library to be used in a non-Ada context,Stand-alone Ada Libraries
@anchor{gnat_ugn/the_gnat_compilation_model id45}@anchor{7f}@anchor{gnat_ugn/the_gnat_compilation_model restrictions-in-stand-alone-libraries}@anchor{80}
@subsubsection Restrictions in Stand-alone Libraries
-The pragmas listed below should be used with caution inside libraries,
-as they can create incompatibilities with other Ada libraries:
+You should use the pragmas listed below with caution inside libraries,
+since they can create incompatibilities with other Ada libraries:
@itemize *
@@ -3906,22 +3914,21 @@ pragma @code{Task_Dispatching_Policy}
pragma @code{Unreserve_All_Interrupts}
@end itemize
-When using a library that contains such pragmas, the user must make sure
-that all libraries use the same pragmas with the same values. Otherwise,
-@code{Program_Error} will
-be raised during the elaboration of the conflicting
-libraries. The usage of these pragmas and its consequences for the user
-should therefore be well documented.
+When using a library that contains such pragmas, the user of the
+library must ensure that all libraries use the same pragmas with the
+same values. Otherwise, @code{Program_Error} will be raised during the
+elaboration of the conflicting libraries. You should document the
+usage of these pragmas and its consequences for the user.
Similarly, the traceback in the exception occurrence mechanism should be
enabled or disabled in a consistent manner across all libraries.
-Otherwise, Program_Error will be raised during the elaboration of the
+Otherwise, @code{Program_Error} will be raised during the elaboration of the
conflicting libraries.
-If the @code{Version} or @code{Body_Version}
-attributes are used inside a library, then you need to
+If you use the @code{Version} or @code{Body_Version}
+attributes inside a library, you need to
perform a @code{gnatbind} step that specifies all @code{ALI} files in all
-libraries, so that version identifiers can be properly computed.
+libraries so that version identifiers can be properly computed.
In practice these attributes are rarely used, so this is unlikely
to be a consideration.
@@ -3940,24 +3947,25 @@ to be a consideration.
@geindex Run-Time Library
@geindex rebuilding
-It may be useful to recompile the GNAT library in various debugging or
-experimentation contexts. A project file called
-@code{libada.gpr} is provided to that effect and can be found in
-the directory containing the GNAT library. The location of this
-directory depends on the way the GNAT environment has been installed and can
-be determined by means of the command:
+You may need to recompile the GNAT library in various debugging or
+experimentation contexts. The GNAT distribution provides a project
+file called @code{libada.gpr} to do that; it can be found in the
+directory containing the GNAT library. The location of this directory
+depends on the way the GNAT environment has been installed and can be
+determined by means of the command:
@example
$ gnatls -v
@end example
The last entry in the source search path usually contains the
-gnat library (the @code{adainclude} directory). This project file contains its
-own documentation and in particular the set of instructions needed to rebuild a
-new library and to use it.
+GNAT library (the @code{adainclude} directory).
+
+This project file contains its own documentation and, in particular, the
+set of instructions needed to rebuild a new library and to use it.
Note that rebuilding the GNAT Run-Time is only recommended for temporary
-experiments or debugging, and is not supported.
+experiments or debugging and is not supported for other purposes.
@geindex Conditional compilation
@@ -3983,7 +3991,7 @@ gnatprep preprocessor utility.
@subsection Modeling Conditional Compilation in Ada
-It is often necessary to arrange for a single source program
+You may want to arrange for a single source program
to serve multiple purposes, where it is compiled in different
ways to achieve these different goals. Some examples of the
need for this feature are
@@ -4004,21 +4012,21 @@ Turning debugging features on and off
Arranging for a program to compile with different compilers
@end itemize
-In C, or C++, the typical approach would be to use the preprocessor
-that is defined as part of the language. The Ada language does not
+In C, or C++, the typical approach is to use the preprocessor
+defined as part of the language. The Ada language does not
contain such a feature. This is not an oversight, but rather a very
deliberate design decision, based on the experience that overuse of
the preprocessing features in C and C++ can result in programs that
are extremely difficult to maintain. For example, if we have ten
switches that can be on or off, this means that there are a thousand
separate programs, any one of which might not even be syntactically
-correct, and even if syntactically correct, the resulting program
+correct, and, even if syntactically correct,
might not work correctly. Testing all combinations can quickly become
impossible.
-Nevertheless, the need to tailor programs certainly exists, and in
+Nevertheless, the need to tailor programs certainly exists and in
this section we will discuss how this can
-be achieved using Ada in general, and GNAT in particular.
+be achieved using Ada in general and GNAT in particular.
@menu
* Use of Boolean Constants::
@@ -4049,7 +4057,7 @@ end if;
Not only will the code inside the @code{if} statement not be executed if
the constant Boolean is @code{False}, but it will also be completely
deleted from the program.
-However, the code is only deleted after the @code{if} statement
+However, the code is only deleted after the @code{if} statement block
has been checked for syntactic and semantic correctness.
(In contrast, with preprocessors the code is deleted before the
compiler ever gets to see it, so it is not checked until the switch
@@ -4068,9 +4076,9 @@ package Config is
end Config;
@end example
-The @code{Config} package exists in multiple forms for the various targets,
+You would write the @code{Config} package multiple forms for various targets,
with an appropriate script selecting the version of @code{Config} needed.
-Then any other unit requiring conditional compilation can do a `with'
+Then, any other unit requiring conditional compilation can do a `with'
of @code{Config} to make the constants visible.
@node Debugging - A Special Case,Conditionalizing Declarations,Use of Boolean Constants,Modeling Conditional Compilation in Ada
@@ -4081,7 +4089,7 @@ of @code{Config} to make the constants visible.
A common use of conditional code is to execute statements (for example
dynamic checks, or output of intermediate results) under control of a
debug switch, so that the debugging behavior can be turned on and off.
-This can be done using a Boolean constant to control whether the code
+You can do this by using a Boolean constant to control whether the debug code
is active:
@example
@@ -4100,14 +4108,14 @@ end if;
@geindex pragma Assert
-Since this is a common case, there are special features to deal with
-this in a convenient manner. For the case of tests, Ada 2005 has added
-a pragma @code{Assert} that can be used for such tests. This pragma is modeled
-on the @code{Assert} pragma that has always been available in GNAT, so this
-feature may be used with GNAT even if you are not using Ada 2005 features.
-The use of pragma @code{Assert} is described in the
-@cite{GNAT_Reference_Manual}, but as an
-example, the last test could be written:
+Since this is a common case, GNAT provides special features to deal
+with this in a convenient manner. For the case of tests, Ada 2005 has
+added a pragma @code{Assert} that you can use for such tests. This pragma
+is modeled on the @code{Assert} pragma that has always been available in
+GNAT, so you can use this feature with GNAT even if you are not using
+Ada 2005 features. The use of pragma @code{Assert} is described in the
+@cite{GNAT_Reference_Manual}, but as an example, the last test could
+be written:
@example
pragma Assert (Temperature <= 999.0, "Temperature Crazy");
@@ -4119,10 +4127,10 @@ or simply
pragma Assert (Temperature <= 999.0);
@end example
-In both cases, if assertions are active and the temperature is excessive,
-the exception @code{Assert_Failure} will be raised, with the given string in
-the first case or a string indicating the location of the pragma in the second
-case used as the exception message.
+In both cases, if assertions are active and the temperature is
+excessive, the exception @code{Assert_Failure} is raised with the
+exception message using the specified string in the first case or a
+string indicating the location of the pragma in the second case.
@geindex pragma Assertion_Policy
@@ -4131,9 +4139,9 @@ pragma.
@geindex -gnata switch
-This is an Ada 2005 pragma which is implemented in all modes by
+This is an Ada 2005 pragma that is implemented in all modes by
GNAT. Alternatively, you can use the @code{-gnata} switch
-to enable assertions from the command line, which applies to
+to enable assertions from the command line, which also applies to
all versions of Ada.
@geindex pragma Debug
@@ -4145,11 +4153,11 @@ For the example above with the @code{Put_Line}, the GNAT-specific pragma
pragma Debug (Put_Line ("got to the first stage!"));
@end example
-If debug pragmas are enabled, the argument, which must be of the form of
-a procedure call, is executed (in this case, @code{Put_Line} will be called).
-Only one call can be present, but of course a special debugging procedure
-containing any code you like can be included in the program and then
-called in a pragma @code{Debug} argument as needed.
+If debug pragmas are enabled, the argument, which must be of the form
+of a procedure call, is executed (in this case, @code{Put_Line} is
+called). You can specify only one call, but you can of course include
+a special debugging procedure containing any code you like in the
+program and call it in a pragma @code{Debug} argument as needed.
One advantage of pragma @code{Debug} over the @code{if Debugging then}
construct is that pragma @code{Debug} can appear in declarative contexts,
@@ -4158,16 +4166,16 @@ been elaborated.
@geindex pragma Debug_Policy
-Debug pragmas are enabled using either the @code{-gnata} switch that also
+You can enable debug pragmas using either the @code{-gnata} switch that also
controls assertions, or with a separate Debug_Policy pragma.
The latter pragma is new in the Ada 2005 versions of GNAT (but it can be used
-in Ada 95 and Ada 83 programs as well), and is analogous to
+in Ada 95 and Ada 83 programs as well) and is analogous to
pragma @code{Assertion_Policy} to control assertions.
@code{Assertion_Policy} and @code{Debug_Policy} are configuration pragmas,
-and thus they can appear in @code{gnat.adc} if you are not using a
-project file, or in the file designated to contain configuration pragmas
+and thus can appear in @code{gnat.adc} if you are not using a
+project file or in the file designated to contain configuration pragmas
in a project file.
They then apply to all subsequent compilations. In practice the use of
the @code{-gnata} switch is often the most convenient method of controlling
@@ -4248,7 +4256,7 @@ for the little endian case. Since a powerful subset of Ada expression
notation is usable for creating static constants, clever use of this
feature can often solve quite difficult problems in conditionalizing
compilation (note incidentally that in Ada 95, the little endian
-constant was introduced as @code{System.Default_Bit_Order}, so you do not
+constant was introduced as @code{System.Default_Bit_Order}, so you don’t
need to define this one yourself).
@node Use of Alternative Implementations,Preprocessing,Conditionalizing Declarations,Modeling Conditional Compilation in Ada
@@ -4257,16 +4265,16 @@ need to define this one yourself).
In some cases, none of the approaches described above are adequate. This
-can occur for example if the set of declarations required is radically
+can occur, for example, if the set of declarations required is radically
different for two different configurations.
In this situation, the official Ada way of dealing with conditionalizing
such code is to write separate units for the different cases. As long as
-this does not result in excessive duplication of code, this can be done
+this doesn’t result in excessive duplication of code, you can do this
without creating maintenance problems. The approach is to share common
-code as far as possible, and then isolate the code and declarations
+code as far as possible and then isolate the code and declarations
that are different. Subunits are often a convenient method for breaking
-out a piece of a unit that is to be conditionalized, with separate files
+out a piece of a unit that you need to be conditionalized, with separate files
for different versions of the subunit for different targets, where the
build script selects the right one to give to the compiler.
@@ -4290,9 +4298,9 @@ But this won’t work when @code{Ada_2005} is set to @code{False},
since the @code{then} clause will be illegal for an Ada 95 compiler.
(Recall that although such unreachable code would eventually be deleted
by the compiler, it still needs to be legal. If it uses features
-introduced in Ada 2005, it will be illegal in Ada 95.)
+introduced in Ada 2005, it’s still illegal in Ada 95.)
-So instead we write
+So instead, we write
@example
procedure Insert is separate;
@@ -4321,9 +4329,9 @@ This can also be done with project files’ naming schemes. For example:
for body ("File_Queries.Insert") use "file_queries-insert-2005.ada";
@end example
-Note also that with project files it is desirable to use a different extension
-than @code{ads} / @code{adb} for alternative versions. Otherwise a naming
-conflict may arise through another commonly used feature: to declare as part
+Note also that with project files, you should use a different extension
+than @code{ads} / @code{adb} for alternative versions. Otherwise, a naming
+conflict may arise through another commonly used feature: declaring as part
of the project a set of directories containing all the sources obeying the
default naming scheme.
@@ -4366,24 +4374,22 @@ used for VMS on the ia64
@end itemize
The dummy version @code{s-asthan.adb} simply raises exceptions noting that
-this operating system feature is not available, and the two remaining
+this operating system feature is not available and the two remaining
versions interface with the corresponding versions of VMS to provide
VMS-compatible AST handling. The GNAT build script knows the architecture
and operating system, and automatically selects the right version,
renaming it if necessary to @code{s-asthan.adb} before the run-time build.
-Another style for arranging alternative implementations is through Ada’s
-access-to-subprogram facility.
-In case some functionality is to be conditionally included,
-you can declare an access-to-procedure variable @code{Ref} that is initialized
-to designate a ‘do nothing’ procedure, and then invoke @code{Ref.all}
-when appropriate.
-In some library package, set @code{Ref} to @code{Proc'Access} for some
-procedure @code{Proc} that performs the relevant processing.
-The initialization only occurs if the library package is included in the
-program.
-The same idea can also be implemented using tagged types and dispatching
-calls.
+Another style for arranging alternative implementations is through
+Ada’s access-to-subprogram facility. In case some functionality is to
+be conditionally included, you can declare an access-to-procedure
+variable @code{Ref} that is initialized to designate a ‘do nothing’
+procedure, and then invoke @code{Ref.all} when appropriate. Then, in,
+some library package, set @code{Ref} to @code{Proc'Access} for some
+procedure @code{Proc} that performs the relevant processing. The
+initialization only occurs if the library package is included in the
+program. The same idea can also be implemented using tagged types and
+dispatching calls.
@node Preprocessing,,Use of Alternative Implementations,Modeling Conditional Compilation in Ada
@anchor{gnat_ugn/the_gnat_compilation_model id53}@anchor{8e}@anchor{gnat_ugn/the_gnat_compilation_model preprocessing}@anchor{8f}
@@ -4393,7 +4399,7 @@ calls.
@geindex Preprocessing
Although it is quite possible to conditionalize code without the use of
-C-style preprocessing, as described earlier in this section, it is
+C-style preprocessing, as described in the cases above, it is
nevertheless convenient in some cases to use the C approach. Moreover,
older Ada compilers have often provided some preprocessing capability,
so legacy code may depend on this approach, even though it is not
@@ -4405,9 +4411,9 @@ with legacy code on other compilers, to enable easier transition).
@geindex gnatprep
-The preprocessor may be used in two separate modes. It can be used quite
-separately from the compiler, to generate a separate output source file
-that is then fed to the compiler as a separate step. This is the
+You can use the preprocessor used in two different modes. You can use it
+separately from the compiler to generate a separate output source file,
+which you then feed to the compiler as a separate step. This is the
@code{gnatprep} utility, whose use is fully described in
@ref{90,,Preprocessing with gnatprep}.
@@ -4425,10 +4431,10 @@ The values of the symbols @code{DEBUG} and @code{PRIORITY} can be
defined either on the command line or in a separate file.
The other way of running the preprocessor is even closer to the C style and
-often more convenient. In this approach the preprocessing is integrated into
-the compilation process. The compiler is given the preprocessor input which
-includes @code{#if} lines etc, and then the compiler carries out the
-preprocessing internally and processes the resulting output.
+often more convenient. In this approach, the preprocessing is integrated into
+the compilation process. You pass the compiler the preprocessor input, which
+includes @code{#if} lines etc, and the compiler carries out the
+preprocessing internally and compiles the resulting output.
For more details on this approach, see @ref{91,,Integrated Preprocessing}.
@node Preprocessing with gnatprep,Integrated Preprocessing,Modeling Conditional Compilation in Ada,Conditional Compilation
@@ -4440,11 +4446,10 @@ For more details on this approach, see @ref{91,,Integrated Preprocessing}.
@geindex Preprocessing (gnatprep)
-This section discusses how to use GNAT’s @code{gnatprep} utility for simple
-preprocessing.
-Although designed for use with GNAT, @code{gnatprep} does not depend on any
-special GNAT features.
-For further discussion of conditional compilation in general, see
+This section discusses how to you can use GNAT’s @code{gnatprep} utility
+for simple preprocessing. Although designed for use with GNAT,
+@code{gnatprep} does not depend on any special GNAT features. For
+further discussion of conditional compilation in general, see
@ref{2b,,Conditional Compilation}.
@menu
@@ -4519,8 +4524,8 @@ normally have an @code{ads} or @code{adb} suffix.
@item @code{deffile}
is the full name of a text file containing definitions of
-preprocessing symbols to be referenced by the preprocessor. This argument is
-optional, and can be replaced by the use of the @code{-D} switch.
+preprocessing symbols to be referenced by the preprocessor. You
+can omit this argument and instead use the @code{-D} switch.
@end table
@end itemize
@@ -4536,7 +4541,7 @@ optional, and can be replaced by the use of the @code{-D} switch.
@item @code{--version}
-Display Copyright and version, then exit disregarding all other options.
+Display copyright and version, then exit, disregarding all other options.
@end table
@geindex --help (gnatprep)
@@ -4546,7 +4551,7 @@ Display Copyright and version, then exit disregarding all other options.
@item @code{--help}
-If @code{--version} was not used, display usage and then exit disregarding
+If @code{--version} was not used, display usage and then exit, disregarding
all other options.
@end table
@@ -4571,7 +4576,7 @@ preserving line numbers in the output file.
Causes both preprocessor lines and the lines deleted
by preprocessing to be retained in the output source as comments marked
-with the special string @code{"--! "}. This option will result in line numbers
+with the special string @code{"--! "}. This option also results in line numbers
being preserved in the output file.
@end table
@@ -4582,13 +4587,14 @@ being preserved in the output file.
@item @code{-C}
-Causes comments to be scanned. Normally comments are ignored by gnatprep.
-If this option is specified, then comments are scanned and any $symbol
-substitutions performed as in program text. This is particularly useful
-when structured comments are used (e.g., for programs written in a
-pre-2014 version of the SPARK Ada subset). Note that this switch is not
-available when doing integrated preprocessing (it would be useless in
-this context since comments are ignored by the compiler in any case).
+Causes comments to be scanned. Normally comments are ignored by
+@code{gnatprep}. If you specify this option, @code{gnatprep} scans
+comments and any $symbol substitutions performed as in program
+text. You will find this particularly useful when structured
+comments are used (e.g., for programs written in a pre-2014 version
+of the SPARK Ada subset). This switch is not available
+when doing integrated preprocessing (it would be useless in this
+context since comments are always ignored by the compiler).
@end table
@geindex -D (gnatprep)
@@ -4598,9 +4604,9 @@ this context since comments are ignored by the compiler in any case).
@item @code{-D`symbol'[=`value']}
-Defines a new preprocessing symbol with the specified value. If no value is given
-on the command line, then symbol is considered to be @code{True}. This switch
-can be used in place of a definition file.
+Defines a new preprocessing symbol with the specified value. If you
+don’t specify a value, the symbol is defined to be @code{True}. You can
+use this switch instead of providing a definition file.
@end table
@geindex -r (gnatprep)
@@ -4610,20 +4616,19 @@ can be used in place of a definition file.
@item @code{-r}
-Causes a @code{Source_Reference} pragma to be generated that
+Causes @code{gnatprep} to generate a @code{Source_Reference} pragma that
references the original input file, so that error messages will use
the file name of this original file. The use of this switch implies
-that preprocessor lines are not to be removed from the file, so its
-use will force @code{-b} mode if @code{-c}
-has not been specified explicitly.
+that preprocessor lines are not to be removed from the file, so
+the @code{-b} and @code{-c} are always enabled.
-Note that if the file to be preprocessed contains multiple units, then
-it will be necessary to @code{gnatchop} the output file from
+If the file to be preprocessed contains multiple units, you
+must call @code{gnatchop} on the the output file from
@code{gnatprep}. If a @code{Source_Reference} pragma is present
in the preprocessed file, it will be respected by
@code{gnatchop -r}
so that the final chopped files will correctly refer to the original
-input source file for @code{gnatprep}.
+input source file passed to @code{gnatprep}.
@end table
@geindex -s (gnatprep)
@@ -4655,9 +4660,10 @@ of the host (LF under unix, CR/LF under Windows) is used.
@item @code{-u}
-Causes undefined symbols to be treated as having the value FALSE in the context
-of a preprocessor test. In the absence of this option, an undefined symbol in
-a @code{#if} or @code{#elsif} test will be treated as an error.
+Causes undefined symbols to be treated as having the value @code{False}
+in the context of a preprocessor test. If you don’t specify this
+switch, @code{gnatprep} will treat an undefined symbol in a @code{#if} or
+@code{#elsif} test as an error.
@end table
@geindex -v (gnatprep)
@@ -4667,13 +4673,13 @@ a @code{#if} or @code{#elsif} test will be treated as an error.
@item @code{-v}
-Verbose mode: generates more output about work done.
+Verbose mode: generates more output about what is done.
@end table
-Note: if neither @code{-b} nor @code{-c} is present,
+Note: if you don’t specify either @code{-b} or @code{-c},
then preprocessor lines and
-deleted lines are completely removed from the output, unless -r is
-specified, in which case -b is assumed.
+deleted lines are completely removed from the output, unless you specify
+@code{-r}, in which case @code{gnatprep} enables the @code{-b} switch.
@node Form of Definitions File,Form of Input Text for gnatprep,Switches for gnatprep,Preprocessing with gnatprep
@anchor{gnat_ugn/the_gnat_compilation_model form-of-definitions-file}@anchor{99}@anchor{gnat_ugn/the_gnat_compilation_model id58}@anchor{9a}
@@ -4701,19 +4707,19 @@ A string literal using normal Ada syntax, or
Any sequence of characters from the set @{letters, digits, period, underline@}.
@end itemize
-Comment lines may also appear in the definitions file, starting with
-the usual @code{--},
-and comments may be added to the definitions lines.
+You may also place comment lines in the definitions file, starting with
+the usual @code{--}
+and comments may be added to the end of each definition line.
@node Form of Input Text for gnatprep,,Form of Definitions File,Preprocessing with gnatprep
@anchor{gnat_ugn/the_gnat_compilation_model form-of-input-text-for-gnatprep}@anchor{9b}@anchor{gnat_ugn/the_gnat_compilation_model id59}@anchor{9c}
@subsubsection Form of Input Text for @code{gnatprep}
-The input text may contain preprocessor conditional inclusion lines,
+The input text contains preprocessor conditional inclusion lines
as well as general symbol substitution sequences.
-The preprocessor conditional inclusion commands have the form:
+Preprocessor conditional inclusion commands have the form:
@example
#if <expression> [then]
@@ -4748,26 +4754,11 @@ In this example, <expression> is defined by the following grammar:
<expression> ::= ( <expression> )
@end example
-Note the following restriction: it is not allowed to have “and” or “or”
-following “not” in the same expression without parentheses. For example, this
-is not allowed:
-
-@example
-not X or Y
-@end example
-
-This can be expressed instead as one of the following forms:
-
-@example
-(not X) or Y
-not (X or Y)
-@end example
-
-For the first test (<expression> ::= <symbol>) the symbol must have
-either the value true or false, that is to say the right-hand of the
+For the first test, (<expression> ::= <symbol>), the symbol must have
+either the value true or false. The right-hand of the
symbol definition must be one of the (case-insensitive) literals
-@code{True} or @code{False}. If the value is true, then the
-corresponding lines are included, and if the value is false, they are
+@code{True} or @code{False}. If the value is true, the
+corresponding lines are included and if the value is false, they are
excluded.
When comparing a symbol to an integer, the integer is any non negative
@@ -4781,34 +4772,32 @@ switch on the command line. Otherwise, the test is false.
The equality tests are case insensitive, as are all the preprocessor lines.
-If the symbol referenced is not defined in the symbol definitions file,
-then the effect depends on whether or not switch @code{-u}
-is specified. If so, then the symbol is treated as if it had the value
-false and the test fails. If this switch is not specified, then
-it is an error to reference an undefined symbol. It is also an error to
-reference a symbol that is defined with a value other than @code{True}
-or @code{False}.
-
-The use of the @code{not} operator inverts the sense of this logical test.
-The @code{not} operator cannot be combined with the @code{or} or @code{and}
-operators, without parentheses. For example, “if not X or Y then” is not
-allowed, but “if (not X) or Y then” and “if not (X or Y) then” are.
-
-The @code{then} keyword is optional as shown
-
-The @code{#} must be the first non-blank character on a line, but
-otherwise the format is free form. Spaces or tabs may appear between
-the @code{#} and the keyword. The keywords and the symbols are case
-insensitive as in normal Ada code. Comments may be used on a
-preprocessor line, but other than that, no other tokens may appear on a
-preprocessor line. Any number of @code{elsif} clauses can be present,
-including none at all. The @code{else} is optional, as in Ada.
-
-The @code{#} marking the start of a preprocessor line must be the first
-non-blank character on the line, i.e., it must be preceded only by
-spaces or horizontal tabs.
-
-Symbol substitution outside of preprocessor lines is obtained by using
+If the symbol referenced is not defined in the symbol definitions
+file, the result depends on whether or not you have specified the
+@code{-u} switch. If you have, the symbol is treated as if it had
+the value false and the test fails. If not,
+it’s an error to reference an undefined symbol. It’s also an
+error to reference a symbol that you have defined with a value other than
+@code{True} or @code{False}.
+
+The use of the @code{not} operator inverts the sense of this logical
+test. You can’t combine the @code{not} operator with the @code{or} or
+@code{and} operators without parentheses. For example, you can’t write
+“if not X or Y then” allowed, but can write either “if (not X) or Y
+then” or “if not (X or Y) then”.
+
+The @code{then} keyword is optional, as shown.
+
+You must place the @code{#} in the first non-blank character on a line,
+i.e., it must be preceded only by spaces or horizontal tabs, but
+otherwise the format is free form. You may place spaces or tabs
+between the @code{#} and the keyword. The keywords and the symbols are
+case insensitive, as in normal Ada code. You can write comments on a
+preprocessor line, but other than that, you can’t place any other
+tokens on a preprocessor line. You can have any number of @code{elsif}
+clauses, including none at all. The @code{else} is optional, as in Ada.
+
+You obtain symbol substitution outside of preprocessor lines by using
the sequence:
@example
@@ -4818,12 +4807,12 @@ $symbol
anywhere within a source line, except in a comment or within a
string literal. The identifier
following the @code{$} must match one of the symbols defined in the symbol
-definition file, and the result is to substitute the value of the
+definition file and the resulting output substitutes the value of the
symbol in place of @code{$symbol} in the output file.
-Note that although the substitution of strings within a string literal
-is not possible, it is possible to have a symbol whose defined value is
-a string literal. So instead of setting XYZ to @code{hello} and writing:
+Note that although you can’t substitute strings within a string
+literal, you can have a symbol whose defined value is a string
+literal. So instead of setting XYZ to @code{hello} and writing:
@example
Header : String := "$XYZ";
@@ -4843,12 +4832,12 @@ and then the substitution will occur as desired.
As noted above, a file to be preprocessed consists of Ada source code
-in which preprocessing lines have been inserted. However,
-instead of using @code{gnatprep} to explicitly preprocess a file as a separate
-step before compilation, you can carry out the preprocessing implicitly
-as part of compilation. Such `integrated preprocessing', which is the common
-style with C, is performed when either or both of the following switches
-are passed to the compiler:
+in which preprocessing lines have been inserted. However, instead of
+using @code{gnatprep} to explicitly preprocess a file as a separate step
+before compilation, you can carry out the preprocessing implicitly as
+part of compilation. Such `integrated preprocessing', which is the
+common style with C, is performed when you pass either or both of the
+following switches to the compiler:
@quotation
@@ -4865,15 +4854,14 @@ symbol definition files apply to which sources).
@end itemize
@end quotation
-Integrated preprocessing applies only to Ada source files, it is
+Integrated preprocessing applies only to Ada source files; it’s
not available for configuration pragma files.
-With integrated preprocessing, the output from the preprocessor is not,
-by default, written to any external file. Instead it is passed
-internally to the compiler. To preserve the result of
-preprocessing in a file, either run @code{gnatprep}
-in standalone mode or else supply the @code{-gnateG} switch
-(described below) to the compiler.
+With integrated preprocessing, GNAT doesn’t write the output from the
+preprocessor, by default, to any external file. Instead it’s passed
+internally to the compiler. To preserve the result of preprocessing in
+a file, either run @code{gnatprep} in standalone mode or supply the
+@code{-gnateG} switch to the compiler.
When using project files:
@@ -4883,13 +4871,13 @@ When using project files:
@itemize *
@item
-the builder switch @code{-x} should be used if any Ada source is
-compiled with @code{gnatep=}, so that the compiler finds the
+you should use the builder switch @code{-x} if any Ada source is
+compiled with @code{gnatep=} so that the compiler finds the
`preprocessor data file'.
@item
-the preprocessing data file and the symbol definition files should be
-located in the source directories of the project.
+you should place the preprocessing data file and the symbol
+definition files in the source directories of the project.
@end itemize
@end quotation
@@ -4935,7 +4923,7 @@ A preprocessor control line
can optionally identify a `definition file' that assigns values to
preprocessor symbols, as well as a list of switches that relate to
preprocessing.
-Empty lines and comments (using Ada syntax) are also permitted, with no
+You can also include empty lines and comments (using Ada syntax), with no
semantic effect.
Here’s an example of a preprocessor data file:
@@ -4976,8 +4964,8 @@ A preprocessor control line has the following syntax:
@end example
@end quotation
-Thus each preprocessor control line starts with either a literal string or
-the character ‘*’:
+Thus, you start each preprocessor control line either a literal
+string or the character ‘*’:
@itemize *
@@ -4993,17 +4981,18 @@ that are not specified explicitly on other lines (the order of the lines is not
significant).
@end itemize
-It is an error to have two lines with the same file name or two
-lines starting with the character ‘*’.
+You cannot have two lines with the same file name or two
+lines starting with the ‘*’ character.
-After the file name or ‘*’, an optional literal string specifies the name of
-the definition file to be used for preprocessing
-(@ref{99,,Form of Definitions File}). The definition files are found by the
-compiler in one of the source directories. In some cases, when compiling
-a source in a directory other than the current directory, if the definition
-file is in the current directory, it may be necessary to add the current
-directory as a source directory through the @code{-I} switch; otherwise
-the compiler would not find the definition file.
+After the file name or ‘*’, you can place an optional literal string
+to specify the name of the definition file to be used for
+preprocessing (@ref{99,,Form of Definitions File}). The definition
+files are found by the compiler in one of the source directories. In
+some cases, when compiling a source in a directory other than the
+current directory, if the definition file is in the current
+directory, you may need to add the current directory as a
+source directory through the @code{-I} switch; otherwise the
+compiler would not find the definition file.
Finally, switches similar to those of @code{gnatprep} may optionally appear:
@@ -5026,12 +5015,12 @@ with the special string ‘@cite{–!}’.
@item @code{-D`symbol'=`new_value'}
Define or redefine @code{symbol} to have @code{new_value} as its value.
-The permitted form for @code{symbol} is either an Ada identifier, or any Ada reserved word
-aside from @code{if},
-@code{else}, @code{elsif}, @code{end}, @code{and}, @code{or} and @code{then}.
-The permitted form for @code{new_value} is a literal string, an Ada identifier or any Ada reserved
-word. A symbol declared with this switch replaces a symbol with the
-same name defined in a definition file.
+You can write @code{symbol} as either an Ada identifier or any Ada
+reserved word aside from @code{if}, @code{else}, @code{elsif}, @code{end},
+@code{and}, @code{or} and @code{then}. You can write @code{new_value} as a
+literal string, an Ada identifier or any Ada reserved word. A
+symbol declared with this switch replaces a symbol with the same
+name defined in a definition file.
@item @code{-s}
@@ -5040,10 +5029,10 @@ listed on the standard output file.
@item @code{-u}
-Causes undefined symbols to be treated as having the value @code{FALSE}
-in the context
-of a preprocessor test. In the absence of this option, an undefined symbol in
-a @code{#if} or @code{#elsif} test will be treated as an error.
+Causes undefined symbols to be treated as having the value
+@code{FALSE} in the context of a preprocessor test. If you don’t
+specify this switch, an undefined symbol in a @code{#if} or
+@code{#elsif} test is treated as an error.
@end table
@end table
@@ -5054,14 +5043,15 @@ a @code{#if} or @code{#elsif} test will be treated as an error.
@item @code{-gnateD`symbol'[=`new_value']}
-Define or redefine @code{symbol} to have @code{new_value} as its value. If no value
-is supplied, then the value of @code{symbol} is @code{True}.
-The form of @code{symbol} is an identifier, following normal Ada (case-insensitive)
-rules for its syntax, and @code{new_value} is either an arbitrary string between double
-quotes or any sequence (including an empty sequence) of characters from the
-set (letters, digits, period, underline).
-Ada reserved words may be used as symbols, with the exceptions of @code{if},
-@code{else}, @code{elsif}, @code{end}, @code{and}, @code{or} and @code{then}.
+Define or redefine @code{symbol} to have @code{new_value} as its value. If
+you don’t specify a value, the value of @code{symbol} is @code{True}. You
+write @code{symbol} as an identifier, following normal Ada
+(case-insensitive) rules for its syntax, and @code{new_value} as either
+an arbitrary string between double quotes or any sequence (including
+an empty sequence) of characters from the set (letters, digits,
+period, underline). Ada reserved words may be used as symbols, with
+the exceptions of @code{if}, @code{else}, @code{elsif}, @code{end}, @code{and},
+@code{or} and @code{then}.
Examples:
@@ -5086,7 +5076,7 @@ When integrated preprocessing is performed on source file @code{filename.extensi
create or overwrite @code{filename.extension.prep} to contain
the result of the preprocessing.
For example if the source file is @code{foo.adb} then
-the output file will be @code{foo.adb.prep}.
+the output file is @code{foo.adb.prep}.
@end table
@node Mixed Language Programming,GNAT and Other Compilation Models,Conditional Compilation,The GNAT Compilation Model
@@ -5116,14 +5106,14 @@ with a focus on combining Ada with C or C++.
Interfacing Ada with a foreign language such as C involves using
compiler directives to import and/or export entity definitions in each
-language – using @code{extern} statements in C, for instance, and the
+language – using @code{extern} statements in C, for example, and the
@code{Import}, @code{Export}, and @code{Convention} pragmas in Ada.
A full treatment of these topics is provided in Appendix B, section 1
of the Ada Reference Manual.
There are two ways to build a program using GNAT that contains some Ada
sources and some foreign language sources, depending on whether or not
-the main subprogram is written in Ada. Here is a source example with
+the main subprogram is written in Ada. Here’s an example with
the main subprogram in Ada:
@example
@@ -5187,7 +5177,7 @@ $ gcc -c file2.c
@end example
@item
-Then, compile the Ada units to produce a set of object files and ALI
+Then compile the Ada units to produce a set of object files and ALI
files:
@example
@@ -5202,7 +5192,7 @@ $ gnatbind my_main.ali
@end example
@item
-Link the Ada main program, the Ada objects and the other language
+Link the Ada main program, the Ada objects, and the other language
objects:
@example
@@ -5210,7 +5200,7 @@ $ gnatlink my_main.ali file1.o file2.o
@end example
@end itemize
-The last three steps can be grouped in a single command:
+You can merge the last three steps into a single command:
@example
$ gnatmake my_main.adb -largs file1.o file2.o
@@ -5218,18 +5208,19 @@ $ gnatmake my_main.adb -largs file1.o file2.o
@geindex Binder output file
-If the main program is in a language other than Ada, then you may have
-more than one entry point into the Ada subsystem. You must use a special
+If the main program is in a language other than Ada, you may have more
+than one entry point into the Ada subsystem. You must use a special
binder option to generate callable routines that initialize and
finalize the Ada units (@ref{7e,,Binding with Non-Ada Main Programs}).
-Calls to the initialization and finalization routines must be inserted
-in the main program, or some other appropriate point in the code. The
-call to initialize the Ada units must occur before the first Ada
-subprogram is called, and the call to finalize the Ada units must occur
-after the last Ada subprogram returns. The binder will place the
-initialization and finalization subprograms into the
-@code{b~xxx.adb} file where they can be accessed by your C
-sources. To illustrate, we have the following example:
+You must insert calls to the initialization and finalization routines
+in the main program or some other appropriate point in the code. You
+must place the call to initialize the Ada units so that it occurs
+before the first Ada subprogram is called and must place the call to
+finalize the Ada units so it occurs after the last Ada subprogram
+returns. The binder places the initialization and finalization
+subprograms into the @code{b~xxx.adb} file, where they can be
+accessed by your C sources. To illustrate, we have the following
+example:
@example
/* main.c */
@@ -5345,7 +5336,7 @@ GNAT linker not to include the standard startup objects by passing the
@geindex Calling Conventions
-GNAT follows standard calling sequence conventions and will thus interface
+GNAT follows standard calling sequence conventions and will interface
to any other language that also follows these conventions. The following
Convention identifiers are recognized by GNAT:
@@ -5360,33 +5351,25 @@ Convention identifiers are recognized by GNAT:
@item @code{Ada}
-This indicates that the standard Ada calling sequence will be
+This indicates that the standard Ada calling sequence is
used and all Ada data items may be passed without any limitations in the
-case where GNAT is used to generate both the caller and callee. It is also
-possible to mix GNAT generated code and code generated by another Ada
-compiler. In this case, the data types should be restricted to simple
+case where GNAT is used to generate both the caller and callee. You can also
+mix GNAT generated code and code generated by another Ada
+compiler. In this case, you should restrict the data types to simple
cases, including primitive types. Whether complex data types can be passed
-depends on the situation. Probably it is safe to pass simple arrays, such
+depends on the situation. It is probably safe to pass simple arrays, such
as arrays of integers or floats. Records may or may not work, depending
on whether both compilers lay them out identically. Complex structures
involving variant records, access parameters, tasks, or protected types,
are unlikely to be able to be passed.
-Note that in the case of GNAT running
-on a platform that supports HP Ada 83, a higher degree of compatibility
-can be guaranteed, and in particular records are laid out in an identical
-manner in the two compilers. Note also that if output from two different
-compilers is mixed, the program is responsible for dealing with elaboration
-issues. Probably the safest approach is to write the main program in the
-version of Ada other than GNAT, so that it takes care of its own elaboration
-requirements, and then call the GNAT-generated adainit procedure to ensure
-elaboration of the GNAT components. Consult the documentation of the other
-Ada compiler for further details on elaboration.
-
-However, it is not possible to mix the tasking run time of GNAT and
-HP Ada 83, all the tasking operations must either be entirely within
-GNAT compiled sections of the program, or entirely within HP Ada 83
-compiled sections of the program.
+If output from two different compilers is mixed, you are responsible
+for dealing with elaboration issues. Probably the safest approach is
+to write the main program in the version of Ada other than GNAT, so
+it takes care of its own elaboration requirements, and
+call the GNAT-generated adainit procedure to ensure elaboration of
+the GNAT components. Consult the documentation of the other Ada
+compiler for further details on elaboration.
@end table
@geindex Interfacing to Assembly
@@ -5426,7 +5409,7 @@ Equivalent to Assembler.
@item @code{COBOL}
-Data will be passed according to the conventions described
+Data is passed according to the conventions described
in section B.4 of the Ada Reference Manual.
@end table
@@ -5441,7 +5424,7 @@ in section B.4 of the Ada Reference Manual.
@item @code{C}
-Data will be passed according to the conventions described
+Data is passed according to the conventions described
in section B.3 of the Ada Reference Manual.
A note on interfacing to a C ‘varargs’ function:
@@ -5456,7 +5439,7 @@ A note on interfacing to a C ‘varargs’ function:
In C, @code{varargs} allows a function to take a variable number of
arguments. There is no direct equivalent in this to Ada. One
-approach that can be used is to create a C wrapper for each
+approach that you can use is to create a C wrapper for each
different profile and then interface to this C wrapper. For
example, to print an @code{int} value using @code{printf},
create a C function @code{printfi} that takes two arguments, a
@@ -5467,8 +5450,8 @@ interface to @code{printfi}.
It may work on some platforms to directly interface to
a @code{varargs} function by providing a specific Ada profile
for a particular call. However, this does not work on
-all platforms, since there is no guarantee that the
-calling sequence for a two argument normal C function
+all platforms since there is no guarantee that the
+calling sequence for a two-argument normal C function
is the same as for calling a @code{varargs} C function with
the same two arguments.
@end quotation
@@ -5509,7 +5492,7 @@ Equivalent to C.
@item @code{C_Plus_Plus} (or @code{CPP})
-This stands for C++. For most purposes this is identical to C.
+This stands for C++. For most purposes, this is identical to C.
See the separate description of the specialized GNAT pragmas relating to
C++ interfacing for further details.
@end table
@@ -5525,15 +5508,15 @@ C++ interfacing for further details.
@item @code{Fortran}
-Data will be passed according to the conventions described
+Data is passed according to the conventions described
in section B.5 of the Ada Reference Manual.
@item @code{Intrinsic}
This applies to an intrinsic operation, as defined in the Ada
Reference Manual. If a pragma Import (Intrinsic) applies to a subprogram,
-this means that the body of the subprogram is provided by the compiler itself,
-usually by means of an efficient code sequence, and that the user does not
+it means the body of the subprogram is provided by the compiler itself,
+usually by means of an efficient code sequence, and that you don’t
supply an explicit body for it. In an application program, the pragma may
be applied to the following sets of names:
@@ -5541,11 +5524,11 @@ be applied to the following sets of names:
@itemize *
@item
-Rotate_Left, Rotate_Right, Shift_Left, Shift_Right, Shift_Right_Arithmetic.
+@code{Rotate_Left}, @code{Rotate_Right}, @code{Shift_Left}, @code{Shift_Right}, @code{Shift_Right_Arithmetic}.
The corresponding subprogram declaration must have
two formal parameters. The
-first one must be a signed integer type or a modular type with a binary
-modulus, and the second parameter must be of type Natural.
+first must be a signed integer type or a modular type with a binary
+modulus and the second parameter must be of type Natural.
The return type must be the same as the type of the first argument. The size
of this type can only be 8, 16, 32, or 64.
@@ -5565,9 +5548,9 @@ function "/" (D : Distance; T : Time)
pragma Import (Intrinsic, "/");
@end example
-This common idiom is often programmed with a generic definition and an
+You often program this common idiom with a generic definition and an
explicit body. The pragma makes it simpler to introduce such declarations.
-It incurs no overhead in compilation time or code size, because it is
+It incurs no overhead in compilation time or code size because it is
implemented as a single machine instruction.
@item
@@ -5575,14 +5558,14 @@ General subprogram entities. This is used to bind an Ada subprogram
declaration to
a compiler builtin by name with back-ends where such interfaces are
available. A typical example is the set of @code{__builtin} functions
-exposed by the GCC back-end, as in the following example:
+exposed by the @code{gcc} back-end, as in the following example:
@example
function builtin_sqrt (F : Float) return Float;
pragma Import (Intrinsic, builtin_sqrt, "__builtin_sqrtf");
@end example
-Most of the GCC builtins are accessible this way, and as for other
+Most of the @code{gcc} builtins are accessible this way, and as for other
import conventions (e.g. C), it is the user’s responsibility to ensure
that the Ada subprogram profile matches the underlying builtin
expectations.
@@ -5598,10 +5581,10 @@ expectations.
@item @code{Stdcall}
-This is relevant only to Windows implementations of GNAT,
-and specifies that the @code{Stdcall} calling sequence will be used,
-as defined by the NT API. Nevertheless, to ease building
-cross-platform bindings this convention will be handled as a @code{C} calling
+This is relevant only to Windows implementations of GNAT
+and specifies that the @code{Stdcall} calling sequence is used,
+as defined by the NT API. To simplify building
+cross-platform bindings, this convention is handled as a @code{C} calling
convention on non-Windows platforms.
@end table
@@ -5643,8 +5626,8 @@ should provide a stub body that raises @code{Program_Error}.
@end table
GNAT additionally provides a useful pragma @code{Convention_Identifier}
-that can be used to parameterize conventions and allow additional synonyms
-to be specified. For example if you have legacy code in which the convention
+that you can use to parameterize conventions and allow additional synonyms.
+For example, if you have legacy code in which the convention
identifier Fortran77 was used for Fortran, you can use the configuration
pragma:
@@ -5652,16 +5635,16 @@ pragma:
pragma Convention_Identifier (Fortran77, Fortran);
@end example
-And from now on the identifier Fortran77 may be used as a convention
+And from now on, you can use the identifier @code{Fortran77} as a convention
identifier (for example in an @code{Import} pragma) with the same
-meaning as Fortran.
+meaning as @code{Fortran}.
@node Building Mixed Ada and C++ Programs,Partition-Wide Settings,Calling Conventions,Mixed Language Programming
@anchor{gnat_ugn/the_gnat_compilation_model building-mixed-ada-and-c-programs}@anchor{a3}@anchor{gnat_ugn/the_gnat_compilation_model id64}@anchor{a4}
@subsection Building Mixed Ada and C++ Programs
-A programmer inexperienced with mixed-language development may find that
+If you are inexperienced with mixed-language development, you may find that
building an application containing both Ada and C++ code can be a
challenge. This section gives a few hints that should make this task easier.
@@ -5683,12 +5666,12 @@ GNAT supports interfacing with the G++ compiler (or any C++ compiler
generating code that is compatible with the G++ Application Binary
Interface —see @indicateurl{http://itanium-cxx-abi.github.io/cxx-abi/abi.html}).
-Interfacing can be done at 3 levels: simple data, subprograms, and
+You can do interfacing at three levels: simple data, subprograms, and
classes. In the first two cases, GNAT offers a specific @code{Convention C_Plus_Plus}
(or @code{CPP}) that behaves exactly like @code{Convention C}.
Usually, C++ mangles the names of subprograms. To generate proper mangled
names automatically, see @ref{a7,,Generating Ada Bindings for C and C++ headers}).
-This problem can also be addressed manually in two ways:
+You can also address this problem addressed manually in two ways:
@itemize *
@@ -5698,11 +5681,12 @@ by modifying the C++ code in order to force a C convention using
the @code{extern "C"} syntax.
@item
-by figuring out the mangled name (using e.g. @code{nm}) and using it as the
-Link_Name argument of the pragma import.
+by figuring out the mangled name (using e.g. @code{nm} or by looking at the
+assembly code generated by the C++ compiler) and using it as the
+@code{Link_Name} argument of the pragma @code{Import}.
@end itemize
-Interfacing at the class level can be achieved by using the GNAT specific
+You can achieve interfacing at the class level by using the GNAT specific
pragmas such as @code{CPP_Constructor}. See the @cite{GNAT_Reference_Manual} for additional information.
@node Linking a Mixed C++ & Ada Program,A Simple Example,Interfacing to C++,Building Mixed Ada and C++ Programs
@@ -5710,25 +5694,24 @@ pragmas such as @code{CPP_Constructor}. See the @cite{GNAT_Reference_Manual} fo
@subsubsection Linking a Mixed C++ & Ada Program
-Usually the linker of the C++ development system must be used to link
-mixed applications because most C++ systems will resolve elaboration
+Usually the linker, of the C++ development system must be used to link
+mixed applications because most C++ systems resolve elaboration
issues (such as calling constructors on global class instances)
transparently during the link phase. GNAT has been adapted to ease the
-use of a foreign linker for the last phase. Three cases can be
-considered:
+use of a foreign linker for the last phase. We consider three cases:
@itemize *
@item
Using GNAT and G++ (GNU C++ compiler) from the same GCC installation:
-The C++ linker can simply be called by using the C++ specific driver
+You can call the C++ linker by using the C++ specific driver
called @code{g++}.
-Note that if the C++ code uses inline functions, you will need to
-compile your C++ code with the @code{-fkeep-inline-functions} switch in
-order to provide an existing function implementation that the Ada code can
-link with.
+If the C++ code uses inline functions that you plan to call from
+Ada, you need to compile your C++ code with the
+@code{-fkeep-inline-functions} so @code{g++} doesn’t delete these
+functions.
@example
$ g++ -c -fkeep-inline-functions file1.C
@@ -5741,8 +5724,8 @@ Using GNAT and G++ from two different GCC installations: If both
compilers are on the
@geindex PATH
@geindex environment variable; PATH
-@code{PATH}, the previous method may be used. It is
-important to note that environment variables such as
+@code{PATH}, you may use the previous
+method. However, environment variables such as
@geindex C_INCLUDE_PATH
@geindex environment variable; C_INCLUDE_PATH
@code{C_INCLUDE_PATH},
@@ -5751,27 +5734,28 @@ important to note that environment variables such as
@code{GCC_EXEC_PREFIX},
@geindex BINUTILS_ROOT
@geindex environment variable; BINUTILS_ROOT
-@code{BINUTILS_ROOT}, and
+@code{BINUTILS_ROOT}, and
@geindex GCC_ROOT
@geindex environment variable; GCC_ROOT
-@code{GCC_ROOT} will affect both compilers
-at the same time and may make one of the two compilers operate
-improperly if set during invocation of the wrong compiler. It is also
-very important that the linker uses the proper @code{libgcc.a} GCC
-library – that is, the one from the C++ compiler installation. The
-implicit link command as suggested in the @code{gnatmake} command
-from the former example can be replaced by an explicit link command with
-the full-verbosity option in order to verify which library is used:
+@code{GCC_ROOT} affect both
+compilers at the same time and may make one of the two compilers
+operate improperly if set during invocation of the wrong compiler.
+It is also very important that the linker uses the proper
+@code{libgcc.a} @code{gcc} library – that is, the one from the C++
+compiler installation. You can replace the implicit link command as
+suggested in the @code{gnatmake} command from the former example with
+an explicit link command with the full-verbosity option
+in order to verify which library is used:
@example
$ gnatbind ada_unit
$ gnatlink -v -v ada_unit file1.o file2.o --LINK=c++
@end example
-If there is a problem due to interfering environment variables, it can
-be worked around by using an intermediate script. The following example
+If there’s a problem due to interfering environment variables, you can
+work around it by using an intermediate script. The following example
shows the proper script to use when GNAT has not been installed at its
-default location and g++ has been installed at its default location:
+default location and @code{g++} has been installed at its default location:
@example
$ cat ./my_script
@@ -5783,13 +5767,13 @@ $ gnatlink -v -v ada_unit file1.o file2.o --LINK=./my_script
@end example
@item
-Using a non-GNU C++ compiler: The commands previously described can be
+Using a non-GNU C++ compiler: You can use the commands previously described
used to insure that the C++ linker is used. Nonetheless, you need to add
a few more parameters to the link command line, depending on the exception
mechanism used.
-If the @code{setjmp} / @code{longjmp} exception mechanism is used, only the paths
-to the @code{libgcc} libraries are required:
+If you are using the @code{setjmp} / @code{longjmp} exception mechanism, you need only
+inclue the paths to the @code{libgcc} libraries:
@example
$ cat ./my_script
@@ -5800,9 +5784,9 @@ $ gnatlink ada_unit file1.o file2.o --LINK=./my_script
where CC is the name of the non-GNU C++ compiler.
-If the “zero cost” exception mechanism is used, and the platform
+If you are using the “zero cost” exception mechanism and the platform
supports automatic registration of exception tables (e.g., Solaris),
-paths to more objects are required:
+you need to include paths to more objects:
@example
$ cat ./my_script
@@ -5813,10 +5797,10 @@ gcc -print-file-name=crtend.o
$ gnatlink ada_unit file1.o file2.o --LINK=./my_script
@end example
-If the “zero cost exception” mechanism is used, and the platform
+If you are using the “zero cost exception” mechanism is used and the platform
doesn’t support automatic registration of exception tables (e.g., HP-UX
-or AIX), the simple approach described above will not work and
-a pre-linking phase using GNAT will be necessary.
+or AIX), the simple approach described above won’t work and
+a you will need to preform a pre-linking phase using GNAT.
@end itemize
Another alternative is to use the @code{gprbuild} multi-language builder
@@ -5830,12 +5814,12 @@ together automatically in most cases.
The following example, provided as part of the GNAT examples, shows how
to achieve procedural interfacing between Ada and C++ in both
-directions. The C++ class A has two methods. The first method is exported
+directions. The C++ class @code{A} has two methods. The first method is exported
to Ada by the means of an extern C wrapper function. The second method
calls an Ada subprogram. On the Ada side, the C++ calls are modelled by
a limited record with a layout comparable to the C++ class. The Ada
subprogram, in turn, calls the C++ method. So, starting from the C++
-main program, the process passes back and forth between the two
+main program, execution passes back and forth between the two
languages.
Here are the compilation commands:
@@ -5957,13 +5941,13 @@ end Simple_Cpp_Interface;
@subsubsection Interfacing with C++ constructors
-In order to interface with C++ constructors GNAT provides the
+To interface with C++ constructors GNAT provides the
@code{pragma CPP_Constructor} (see the @cite{GNAT_Reference_Manual}
for additional information).
-In this section we present some common uses of C++ constructors
+In this section, we present some common uses of C++ constructors
in mixed-languages programs in GNAT.
-Let us assume that we need to interface with the following
+Let us assume we need to interface with the following
C++ class:
@example
@@ -5978,7 +5962,7 @@ public:
@};
@end example
-For this purpose we can write the following package spec (further
+For this purpose, we can write the following package spec (further
information on how to build this spec is available in
@ref{ae,,Interfacing with C++ at the Class Level} and
@ref{a7,,Generating Ada Bindings for C and C++ headers}).
@@ -6006,10 +5990,10 @@ package Pkg_Root is
end Pkg_Root;
@end example
-On the Ada side the constructor is represented by a function (whose
+On the Ada side, the constructor is represented by a function (whose
name is arbitrary) that returns the classwide type corresponding to
the imported C++ class. Although the constructor is described as a
-function, it is typically a procedure with an extra implicit argument
+function, it’s typically a procedure with an extra implicit argument
(the object being initialized) at the implementation level. GNAT
issues the appropriate call, whatever it is, to get the object
properly initialized.
@@ -6020,10 +6004,10 @@ Constructors can only appear in the following contexts:
@itemize *
@item
-On the right side of an initialization of an object of type @code{T}.
+On the right side of an initialization of an object of type.
@item
-On the right side of an initialization of a record component of type @code{T}.
+On the right side of an initialization of a record component of type.
@item
In an Ada 2005 limited aggregate.
@@ -6037,8 +6021,8 @@ place by an extended return statement.
@end itemize
In a declaration of an object whose type is a class imported from C++,
-either the default C++ constructor is implicitly called by GNAT, or
-else the required C++ constructor must be explicitly called in the
+either the default C++ constructor is implicitly called by GNAT or you must
+explicitly call the required C++ constructor in the
expression that initializes the object. For example:
@example
@@ -6050,12 +6034,12 @@ Obj4 : Root := Constructor (30, 40);
The first two declarations are equivalent: in both cases the default C++
constructor is invoked (in the former case the call to the constructor is
-implicit, and in the latter case the call is explicit in the object
+implicit and in the latter case the call is explicit in the object
declaration). @code{Obj3} is initialized by the C++ non-default constructor
-that takes an integer argument, and @code{Obj4} is initialized by the
+that takes an integer argument and @code{Obj4} is initialized by the
non-default C++ constructor that takes two integers.
-Let us derive the imported C++ class in the Ada side. For example:
+Let’s derive the imported C++ class in the Ada side. For example:
@example
type DT is new Root with record
@@ -6063,8 +6047,8 @@ type DT is new Root with record
end record;
@end example
-In this case the components DT inherited from the C++ side must be
-initialized by a C++ constructor, and the additional Ada components
+In this case, you must initialize the components @code{DT} inherited from
+the C++ side by a C++ constructor and the additional Ada components
of type DT are initialized by GNAT. The initialization of such an
object is done either by default, or by means of a function returning
an aggregate of type DT, or by means of an extension aggregate.
@@ -6077,14 +6061,14 @@ Obj7 : DT := (Constructor (30,40) with C_Value => 50);
The declaration of @code{Obj5} invokes the default constructors: the
C++ default constructor of the parent type takes care of the initialization
-of the components inherited from Root, and GNAT takes care of the default
+of the components inherited from Root and GNAT takes care of the default
initialization of the additional Ada components of type DT (that is,
@code{C_Value} is initialized to value 2009). The order of invocation of
the constructors is consistent with the order of elaboration required by
Ada and C++. That is, the constructor of the parent type is always called
before the constructor of the derived type.
-Let us now consider a record that has components whose type is imported
+Let’s now consider a record that has components whose type is imported
from C++. For example:
@example
@@ -6099,15 +6083,14 @@ type Rec2 (D : Integer := 20) is limited record
end record;
@end example
-The initialization of an object of type @code{Rec2} will call the
-non-default C++ constructors specified for the imported components.
-For example:
+The initialization of an object of type @code{Rec2} calls the non-default
+C++ constructors specified for the imported components. For example:
@example
Obj8 : Rec2 (40);
@end example
-Using Ada 2005 we can use limited aggregates to initialize an object
+Using Ada 2005, we can use limited aggregates to initialize an object
invoking C++ constructors that differ from those specified in the type
declarations. For example:
@@ -6118,17 +6101,17 @@ Obj9 : Rec2 := (Rec => (Data1 => Constructor (15, 16),
@end example
The above declaration uses an Ada 2005 limited aggregate to
-initialize @code{Obj9}, and the C++ constructor that has two integer
+initialize @code{Obj9} and the C++ constructor that has two integer
arguments is invoked to initialize the @code{Data1} component instead
of the constructor specified in the declaration of type @code{Rec1}. In
-Ada 2005 the box in the aggregate indicates that unspecified components
+Ada 2005, the box in the aggregate indicates that unspecified components
are initialized using the expression (if any) available in the component
declaration. That is, in this case discriminant @code{D} is initialized
to value @code{20}, @code{Value} is initialized to value 1000, and the
non-default C++ constructor that handles two integers takes care of
initializing component @code{Data2} with values @code{20,30}.
-In Ada 2005 we can use the extended return statement to build the Ada
+In Ada 2005, we can use the extended return statement to build the Ada
equivalent to C++ non-default constructors. For example:
@example
@@ -6144,26 +6127,26 @@ begin
end Constructor;
@end example
-In this example the extended return statement construct is used to
-build in place the returned object whose components are initialized
-by means of a limited aggregate. Any further action associated with
-the constructor can be placed inside the construct.
+In this example, we use the extended return statement construct to
+build in place the returned object whose components are initialized by
+means of a limited aggregate. We could also place any further action
+associated with the constructor inside the construct.
@node Interfacing with C++ at the Class Level,,Interfacing with C++ constructors,Building Mixed Ada and C++ Programs
@anchor{gnat_ugn/the_gnat_compilation_model id69}@anchor{af}@anchor{gnat_ugn/the_gnat_compilation_model interfacing-with-c-at-the-class-level}@anchor{ae}
@subsubsection Interfacing with C++ at the Class Level
-In this section we demonstrate the GNAT features for interfacing with
+In this section, we demonstrate the GNAT features for interfacing with
C++ by means of an example making use of Ada 2005 abstract interface
types. This example consists of a classification of animals; classes
-have been used to model our main classification of animals, and
+have been used to model our main classification of animals and
interfaces provide support for the management of secondary
classifications. We first demonstrate a case in which the types and
constructors are defined on the C++ side and imported from the Ada
-side, and latter the reverse case.
+side and then the reverse case.
-The root of our derivation will be the @code{Animal} class, with a
+The root of our derivation is the @code{Animal} class, with a
single private attribute (the @code{Age} of the animal), a constructor,
and two public primitives to set and get the value of this attribute.
@@ -6179,7 +6162,7 @@ class Animal @{
@end example
Abstract interface types are defined in C++ by means of classes with pure
-virtual functions and no data members. In our example we will use two
+virtual functions and no data members. In our example we use two
interfaces that provide support for the common management of @code{Carnivore}
and @code{Domestic} animals:
@@ -6211,7 +6194,7 @@ class Dog : Animal, Carnivore, Domestic @{
@};
@end example
-In the following examples we will assume that the previous declarations are
+In the following examples we assume that the previous declarations are
located in a file named @code{animals.h}. The following package demonstrates
how to import these C++ declarations from the Ada side:
@@ -6262,33 +6245,35 @@ package Animals is
end Animals;
@end example
-Thanks to the compatibility between GNAT run-time structures and the C++ ABI,
-interfacing with these C++ classes is easy. The only requirement is that all
-the primitives and components must be declared exactly in the same order in
-the two languages.
+Thanks to the compatibility between GNAT run-time structures and the
+C++ ABI, interfacing with these C++ classes is easy. The only
+requirement is that you must declare all the primitives and components
+exactly in the same order in the two languages.
-Regarding the abstract interfaces, we must indicate to the GNAT compiler by
-means of a @code{pragma Convention (C_Plus_Plus)}, the convention used to pass
-the arguments to the called primitives will be the same as for C++. For the
-imported classes we use @code{pragma Import} with convention @code{C_Plus_Plus}
-to indicate that they have been defined on the C++ side; this is required
-because the dispatch table associated with these tagged types will be built
-in the C++ side and therefore will not contain the predefined Ada primitives
-which Ada would otherwise expect.
+Regarding the abstract interfaces, we must indicate to the GNAT
+compiler, by means of a @code{pragma Convention (C_Plus_Plus)}, that the
+convention used to pass the arguments to the called primitives will be
+the same as for C++. For the imported classes, we use @code{pragma
+Import} with convention @code{C_Plus_Plus} to indicate they have been
+defined on the C++ side; this is required because the dispatch table
+associated with these tagged types will be built in the C++ side and
+therefore will not contain the predefined Ada primitives which Ada
+would otherwise expect.
-As the reader can see there is no need to indicate the C++ mangled names
+As the reader can see, there is no need to indicate the C++ mangled names
associated with each subprogram because it is assumed that all the calls to
these primitives will be dispatching calls. The only exception is the
-constructor, which must be registered with the compiler by means of
-@code{pragma CPP_Constructor} and needs to provide its associated C++
+constructor, which we must register with the compiler by means of
+@code{pragma CPP_Constructor} and we need to provide its associated C++
mangled name because the Ada compiler generates direct calls to it.
-With the above packages we can now declare objects of type Dog on the Ada side
-and dispatch calls to the corresponding subprograms on the C++ side. We can
-also extend the tagged type Dog with further fields and primitives, and
-override some of its C++ primitives on the Ada side. For example, here we have
-a type derivation defined on the Ada side that inherits all the dispatching
-primitives of the ancestor from the C++ side.
+With the above packages, we can now declare objects of type @code{Dog} on
+the Ada side and dispatch calls to the corresponding subprograms on
+the C++ side. We can also extend the tagged type @code{Dog} with further
+fields and primitives and override some of its C++ primitives on the
+Ada side. For example, here we have a type derivation defined on the
+Ada side that inherits all the dispatching primitives of the ancestor
+from the C++ side.
@example
with Animals; use Animals;
@@ -6298,11 +6283,11 @@ package Vaccinated_Animals is
end Vaccinated_Animals;
@end example
-It is important to note that, because of the ABI compatibility, the programmer
-does not need to add any further information to indicate either the object
+It is important to note that, because of the ABI compatibility, we
+don’t need to add any further information to indicate either the object
layout or the dispatch table entry associated with each dispatching operation.
-Now let us define all the types and constructors on the Ada side and export
+Now let’s define all the types and constructors on the Ada side and export
them to C++, using the same hierarchy of our previous example:
@example
@@ -6352,7 +6337,7 @@ end Animals;
@end example
Compared with our previous example the only differences are the use of
-@code{pragma Convention} (instead of @code{pragma Import}), and the use of
+@code{pragma Convention} (instead of @code{pragma Import}) and the use of
@code{pragma Export} to indicate to the GNAT compiler that the primitives will
be available to C++. Thanks to the ABI compatibility, on the C++ side there is
nothing else to be done; as explained above, the only requirement is that all
@@ -6400,23 +6385,22 @@ int main ()
@subsection Partition-Wide Settings
-When building a mixed-language application it is important to be aware that
+When building a mixed-language application, you must be aware that
Ada enforces some partition-wide settings that may implicitly impact the
behavior of the other languages.
-This is the case of certain signals that are reserved to the
+This is the case for certain signals that are reserved to the
implementation to implement proper Ada semantics (such as the behavior
of @code{abort} statements).
-
It means that the Ada part of the application may override signal handlers
that were previously installed by either the system or by other user code.
-If your application requires that either system or user signals be preserved
-then you need to instruct the Ada part not to install its own signal handler.
-This is done using @code{pragma Interrupt_State} that provides a general
+If your application requires that either system or user signals be preserved,
+you need to instruct the Ada part not to install its own signal handler.
+You do this using @code{pragma Interrupt_State} that provides a general
mechanism for overriding such uses of interrupts.
-Additionally, @code{pragma Interrupts_System_By_Default} can be used to default
+Additionally, you can use pragma @code{Interrupts_System_By_Default} to default
all interrupts to System.
The set of interrupts for which the Ada run-time library sets a specific signal
@@ -6441,9 +6425,9 @@ Ada.Interrupts.Names.SIGILL
Ada.Interrupts.Names.SIGABRT
@end itemize
-The run-time library can be instructed not to install its signal handler for a
-particular signal by using the configuration pragma @code{Interrupt_State} in the
-Ada code. For example:
+You can instruct the run-time library not to install its signal
+handler for a particular signal by using the configuration pragma
+@code{Interrupt_State} in the Ada code. For example:
@example
pragma Interrupt_State (Ada.Interrupts.Names.SIGSEGV, System);
@@ -6469,13 +6453,13 @@ while @code{SIGABRT} is used to asynchronously abort an action or a task.
@geindex C++ headers (binding generation)
-GNAT includes a binding generator for C and C++ headers which is
+GNAT includes a binding generator for C and C++ headers, which is
intended to do 95% of the tedious work of generating Ada specs from C
or C++ header files.
-Note that this capability is not intended to generate 100% correct Ada specs,
-and will is some cases require manual adjustments, although it can often
-be used out of the box in practice.
+This capability is not intended to generate 100% correct Ada specs and
+it will in some cases require you to make manual adjustments, although
+it can often be used out of the box in practice.
Some of the known limitations include:
@@ -6491,15 +6475,15 @@ as comments, to be completed manually if needed.
some extensions (e.g. vector types) are not supported
@item
-pointers to pointers are mapped to System.Address
+pointers to pointers are mapped to @code{System.Address}
@item
-identifiers with identical name (except casing) may generate compilation
-errors (e.g. @code{shm_get} vs @code{SHM_GET}).
+identifiers with names that are identical except for casing may generate
+compilation errors (e.g. @code{shm_get} vs @code{SHM_GET}).
@end itemize
The code is generated using Ada 2012 syntax, which makes it easier to interface
-with other languages. In most cases you can still use the generated binding
+with other languages. In most cases, you can still use the generated binding
even if your code is compiled using earlier versions of Ada (e.g. @code{-gnat95}).
@menu
@@ -6514,9 +6498,9 @@ even if your code is compiled using earlier versions of Ada (e.g. @code{-gnat95}
@subsubsection Running the Binding Generator
-The binding generator is part of the @code{gcc} compiler and can be
-invoked via the @code{-fdump-ada-spec} switch, which will generate Ada
-spec files for the header files specified on the command line, and all
+The binding generator is part of the @code{gcc} compiler and you can
+invoke it via the @code{-fdump-ada-spec} switch, which generates Ada
+spec files for the header files specified on the command line and all
header files needed by these files transitively. For example:
@example
@@ -6524,17 +6508,17 @@ $ gcc -c -fdump-ada-spec -C /usr/include/time.h
$ gcc -c *.ads
@end example
-will generate, under GNU/Linux, the following files: @code{time_h.ads},
+generates, under GNU/Linux, the following files: @code{time_h.ads},
@code{bits_time_h.ads}, @code{stddef_h.ads}, @code{bits_types_h.ads} which
-correspond to the files @code{/usr/include/time.h},
-@code{/usr/include/bits/time.h}, etc…, and then compile these Ada specs.
-That is to say, the name of the Ada specs is in keeping with the relative path
+correspond to the files @code{/usr/include/time.h}, and
+@code{/usr/include/bits/time.h} and then compile these Ada specs.
+The name of the Ada specs is consistent with the relative path
under @code{/usr/include/} of the header files. This behavior is specific to
paths ending with @code{/include/}; in all the other cases, the name of the
Ada specs is derived from the simple name of the header files instead.
The @code{-C} switch tells @code{gcc} to extract comments from headers,
-and will attempt to generate corresponding Ada comments.
+and attempt to generate corresponding Ada comments.
If you want to generate a single Ada file and not the transitive closure, you
can use instead the @code{-fdump-ada-spec-slim} switch.
@@ -6553,11 +6537,11 @@ is for example the case with @code{Xlib.h} under GNU/Linux:
$ gcc -c -fdump-ada-spec -DXLIB_ILLEGAL_ACCESS -C /usr/include/X11/Xlib.h
@end example
-The above will generate more complete bindings than a straight call without
+The above generates more complete bindings than a call without
the @code{-DXLIB_ILLEGAL_ACCESS} switch.
-In other cases, it is not possible to parse a header file in a stand-alone
-manner, because other include files need to be included first. In this
+In other cases, you can’t parse a header file in a stand-alone
+manner because other include files need to be included first. In this
case, the solution is to create a small header file including the needed
@code{#include} and possible @code{#define} directives. For example, to
generate Ada bindings for @code{readline/readline.h}, you need to first
@@ -6580,15 +6564,15 @@ $ gcc -c -fdump-ada-spec readline1.h
@subsubsection Generating Bindings for C++ Headers
-Generating bindings for C++ headers is done using the same options, always
-with the `g++' compiler. Note that generating Ada spec from C++ headers is a
+Generating bindings for C++ headers is done using the same options, but
+with the @code{g++} compiler. Note that generating Ada spec from C++ headers is a
much more complex job and support for C++ headers is much more limited that
support for C headers. As a result, you will need to modify the resulting
bindings by hand more extensively when using C++ headers.
-In this mode, C++ classes will be mapped to Ada tagged types, constructors
-will be mapped using the @code{CPP_Constructor} pragma, and when possible,
-multiple inheritance of abstract classes will be mapped to Ada interfaces
+In this mode, C++ classes are mapped to Ada tagged types, constructors
+are mapped using the @code{CPP_Constructor} pragma, and when possible,
+multiple inheritance of abstract classes are mapped to Ada interfaces
(see the `Interfacing to C++' section in the @cite{GNAT Reference Manual}
for additional information on interfacing to C++).
@@ -6699,8 +6683,8 @@ all header files that these headers depend upon).
@item @code{-fdump-ada-spec-slim}
-Generate Ada spec files for the header files specified on the command line
-only.
+Only generate Ada spec files for the header files specified on the
+command line.
@end table
@geindex -fada-spec-parent (gcc)
@@ -6733,9 +6717,9 @@ Extract comments from headers and generate Ada comments in the Ada spec files.
@geindex C headers (binding generation)
-GNAT includes a C header generator for Ada specifications which supports
-Ada types that have a direct mapping to C types. This includes in particular
-support for:
+GNAT includes a C header generator for Ada specifications that
+supports Ada types that have a direct mapping to C types. This
+specifically includes support for:
@itemize *
@@ -6773,18 +6757,18 @@ Subprogram declarations
The C header generator is part of the GNAT compiler and can be invoked via
-the @code{-gnatceg} combination of switches, which will generate a @code{.h}
+the @code{-gnatceg} switch, which generates a @code{.h}
file corresponding to the given input file (Ada spec or body). Note that
-only spec files are processed in any case, so giving a spec or a body file
+only spec files are processed, so giving a spec or a body file
as input is equivalent. For example:
@example
$ gcc -c -gnatceg pack1.ads
@end example
-will generate a self-contained file called @code{pack1.h} including
-common definitions from the Ada Standard package, followed by the
-definitions included in @code{pack1.ads}, as well as all the other units
+generates a self-contained file called @code{pack1.h} including
+common definitions from the Ada Standard package followed by the
+definitions included in @code{pack1.ads} as well as all the other units
withed by this file.
For instance, given the following Ada files:
@@ -6810,7 +6794,7 @@ package Pack1 is
end Pack1;
@end example
-The above @code{gcc} command will generate the following @code{pack1.h} file:
+The above @code{gcc} command generates the following @code{pack1.h} file:
@example
/* Standard definitions skipped */
@@ -6841,7 +6825,7 @@ call subprograms, reference objects, and constants.
This section compares the GNAT model with the approaches taken in
-other environments, first the C/C++ model and then the mechanism that
+other environments: first the C/C++ model and then the mechanism that
has been used in other Ada systems, in particular those traditionally
used for Ada 83.
@@ -6856,11 +6840,10 @@ used for Ada 83.
@subsection Comparison between GNAT and C/C++ Compilation Models
-The GNAT model of compilation is close to the C and C++ models. You can
+The GNAT compilation model is close to the C and C++ models. You can
think of Ada specs as corresponding to header files in C. As in C, you
don’t need to compile specs; they are compiled when they are used. The
-Ada `with' is similar in effect to the @code{#include} of a C
-header.
+Ada `with' is similar in effect to the @code{#include} of a C header.
One notable difference is that, in Ada, you may compile specs separately
to check them for semantic and syntactic accuracy. This is not always
@@ -6870,7 +6853,7 @@ less specific syntactic or semantic rules.
The other major difference is the requirement for running the binder,
which performs two important functions. First, it checks for
consistency. In C or C++, the only defense against assembling
-inconsistent programs lies outside the compiler, in a makefile, for
+inconsistent programs lies outside the compiler, in a @code{makefile}, for
example. The binder satisfies the Ada requirement that it be impossible
to construct an inconsistent program when the compiler is used in normal
mode.
@@ -6899,9 +6882,9 @@ model, as described in the Ada Reference Manual.
In GNAT, there is no ‘library’ in the normal sense. Instead, the set of
source files themselves acts as the library. Compiling Ada programs does
not generate any centralized information, but rather an object file and
-a ALI file, which are of interest only to the binder and linker.
+a @code{.ali} file, which are of interest only to the binder and linker.
In a traditional system, the compiler reads information not only from
-the source file being compiled, but also from the centralized library.
+the source file being compiled but also from the centralized library.
This means that the effect of a compilation depends on what has been
previously compiled. In particular:
@@ -6946,7 +6929,7 @@ depended on the source file being modified.
@end itemize
The most important result of these differences is that order of compilation
-is never significant in GNAT. There is no situation in which one is
+is never significant in GNAT. There is no situation in which you are
required to do one compilation before another. What shows up as order of
compilation requirements in the traditional Ada library becomes, in
GNAT, simple source dependencies; in other words, there is only a set
@@ -6972,27 +6955,27 @@ used with tools designed for other languages.
@subsection Using Other Utility Programs with GNAT
-The object files generated by GNAT are in standard system format and in
-particular the debugging information uses this format. This means
+The object files generated by GNAT are in standard system format and, in
+particular, the debugging information uses this format. This means
programs generated by GNAT can be used with existing utilities that
depend on these formats.
In general, any utility program that works with C will also often work with
Ada programs generated by GNAT. This includes software utilities such as
-gprof (a profiling program), gdb (the FSF debugger), and utilities such
-as Purify.
+@code{gprof} (a profiling program), @code{gdb} (the FSF debugger), and utilities such
+as @code{Purify}.
@node The External Symbol Naming Scheme of GNAT,,Using Other Utility Programs with GNAT,Using GNAT Files with External Tools
@anchor{gnat_ugn/the_gnat_compilation_model id80}@anchor{c4}@anchor{gnat_ugn/the_gnat_compilation_model the-external-symbol-naming-scheme-of-gnat}@anchor{c5}
@subsection The External Symbol Naming Scheme of GNAT
-In order to interpret the output from GNAT, when using tools that are
-originally intended for use with other languages, it is useful to
+To interpret the output from GNAT when using tools that are
+originally intended for use with other languages, you need to
understand the conventions used to generate link names from the Ada
entity names.
-All link names are in all lowercase letters. With the exception of library
+All link names are in all lowercase. With the exception of library
procedure names, the mechanism used is simply to use the full expanded
Ada name with dots replaced by double underscores. For example, suppose
we have the following package spec:
@@ -7007,7 +6990,7 @@ end QRS;
The variable @code{MN} has a full expanded Ada name of @code{QRS.MN}, so
the corresponding link name is @code{qrs__mn}.
-Of course if a @code{pragma Export} is used this may be overridden:
+Of course if you use a pragma @code{Export}, you maye override this:
@example
package Exports is
@@ -7030,14 +7013,14 @@ arises between the required name @code{_main} for the C main program,
and the name we would otherwise assign to an Ada library level procedure
called @code{Main} (which might well not be the main program).
-To avoid this ambiguity, we attach the prefix @code{_ada_} to such
+To avoid this ambiguity, GNAT adds the prefix @code{_ada_} to such
names. So if we have a library level procedure such as:
@example
procedure Hello (S : String);
@end example
-the external name of this procedure will be @code{_ada_hello}.
+the external name of this procedure is @code{_ada_hello}.
@c -- Example: A |withing| unit has a |with| clause, it |withs| a |withed| unit
@@ -17598,7 +17581,7 @@ Other GNAT utilities are described elsewhere in this manual:
@geindex gnatclean
-@code{gnatclean} is a tool that allows the deletion of files produced by the
+@code{gnatclean} is a tool that deletes some files produced by the
compiler, binder and linker, including ALI files, object files, tree files,
expanded source files, library files, interface copy source files, binder
generated files and executable files.
@@ -17614,7 +17597,7 @@ generated files and executable files.
@subsection Running @code{gnatclean}
-The @code{gnatclean} command has the form:
+You run the @code{gnatclean} command as follow:
@quotation
@@ -17623,15 +17606,15 @@ $ gnatclean switches names
@end example
@end quotation
-where @code{names} is a list of source file names. Suffixes @code{.ads} and
-@code{adb} may be omitted. If a project file is specified using switch
-@code{-P}, then @code{names} may be completely omitted.
+where @code{names} is a list of source file names. You may omit suffixes @code{.ads} and
+@code{adb}. If a project file is specified using switch
+@code{-P}, then you may completely omit @code{names}.
-In normal mode, @code{gnatclean} delete the files produced by the compiler and,
-if switch @code{-c} is not specified, by the binder and
-the linker. In informative-only mode, specified by switch
-@code{-n}, the list of files that would have been deleted in
-normal mode is listed, but no file is actually deleted.
+In normal mode, @code{gnatclean} deletes the files produced by the compiler and,
+if switch @code{-c} is not specified, produced by the binder and
+linker. In information-only mode, specified by switch
+@code{-n}, @code{gnatclean} lists the files that would have been deleted in
+normal mode, but doesn’t actually delete any files.
@node Switches for gnatclean,,Running gnatclean,The File Cleanup Utility gnatclean
@anchor{gnat_ugn/gnat_utility_programs id4}@anchor{13e}@anchor{gnat_ugn/gnat_utility_programs switches-for-gnatclean}@anchor{13f}
@@ -17647,7 +17630,7 @@ normal mode is listed, but no file is actually deleted.
@item @code{--version}
-Display copyright and version, then exit disregarding all other options.
+Display copyright and version, then exit, disregarding all other options.
@end table
@geindex --help (gnatclean)
@@ -17657,19 +17640,19 @@ Display copyright and version, then exit disregarding all other options.
@item @code{--help}
-If @code{--version} was not used, display usage, then exit disregarding
-all other options.
+If @code{--version} was not specified, display usage, then exit
+disregarding all other options.
@item @code{--subdirs=`subdir'}
-Actual object directory of each project file is the subdirectory subdir of the
-object directory specified or defaulted in the project file.
+Actual object directory of each project file, which is the
+subdirectory @code{subdir} of the object directory specified or defaulted
+in the project file.
@item @code{--unchecked-shared-lib-imports}
By default, shared library projects are not allowed to import static library
-projects. When this switch is used on the command line, this restriction is
-relaxed.
+projects. When this switch is specified, this restriction is lifted.
@end table
@geindex -c (gnatclean)
@@ -17691,7 +17674,8 @@ files, interface copy files, binder generated files and executable files.
@item @code{-D `dir'}
-Indicate that ALI and object files should normally be found in directory @code{dir}.
+Indicate that ALI and object files should normally be found in
+directory @code{dir}.
@end table
@geindex -F (gnatclean)
@@ -17701,10 +17685,10 @@ Indicate that ALI and object files should normally be found in directory @code{d
@item @code{-F}
-When using project files, if some errors or warnings are detected during
-parsing and verbose mode is not in effect (no use of switch
--v), then error lines start with the full path name of the project
-file, rather than its simple file name.
+When using project files, if some errors or warnings are detected
+during parsing and verbose mode is not in effect (the switch
+@code{-v} is not specified), error lines start with the full path
+name of the project file, rather than its simple file name.
@end table
@geindex -h (gnatclean)
@@ -17735,11 +17719,11 @@ that would have been deleted if this switch was not specified.
@item @code{-P`project'}
-Use project file @code{project}. Only one such switch can be used.
-When cleaning a project file, the files produced by the compilation of the
-immediate sources or inherited sources of the project files are to be
-deleted. This is not depending on the presence or not of executable names
-on the command line.
+Use project file @code{project}. You can specify only one such switch.
+When cleaning a project file, @code{gnatclean} deletes the files
+produced by the compilation of the immediate sources or inherited
+sources of the project files. This does not depend on whether or not
+you include executable names on the command line.
@end table
@geindex -q (gnatclean)
@@ -17750,8 +17734,8 @@ on the command line.
@item @code{-q}
Quiet output. If there are no errors, do not output anything, except in
-verbose mode (switch -v) or in informative-only mode
-(switch -n).
+verbose mode (@code{-v}) or in information-only mode
+(@code{-n}).
@end table
@geindex -r (gnatclean)
@@ -17761,10 +17745,11 @@ verbose mode (switch -v) or in informative-only mode
@item @code{-r}
-When a project file is specified (using switch -P),
-clean all imported and extended project files, recursively. If this switch
-is not specified, only the files related to the main project file are to be
-deleted. This switch has no effect if no project file is specified.
+When a project file is specified (using @code{-P}), clean all
+imported and extended project files, recursively. If you don’t
+specify this switch, @code{gnatclean} only deletes the files related to
+the main project file. This switch has no effect if you don’t
+specify a project file.
@end table
@geindex -v (gnatclean)
@@ -17846,7 +17831,7 @@ where @code{gnatclean} was invoked.
@code{gnatls} is a tool that outputs information about compiled
units. It gives the relationship between objects, unit names and source
-files. It can also be used to check the source dependencies of a unit
+files. You can also use it to check the source dependencies of a unit
as well as various characteristics.
@menu
@@ -17861,7 +17846,7 @@ as well as various characteristics.
@subsection Running @code{gnatls}
-The @code{gnatls} command has the form
+You run the @code{gnatls} command as follows:
@quotation
@@ -17872,15 +17857,15 @@ $ gnatls switches object_or_ali_file
The main argument is the list of object or @code{ali} files
(see @ref{28,,The Ada Library Information Files})
-for which information is requested.
+for which you are requesting information.
-In normal mode, without additional option, @code{gnatls} produces a
-four-column listing. Each line represents information for a specific
+In the default mode, without additional options, @code{gnatls} produces a
+four-column listing. Each line contains information for a specific
object. The first column gives the full path of the object, the second
-column gives the name of the principal unit in this object, the third
+column gives the name of the principal unit in the object, the third
column gives the status of the source and the fourth column gives the
full path of the source representing this unit.
-Here is a simple example of use:
+Here’s a simple example:
@quotation
@@ -17897,9 +17882,9 @@ $ gnatls *.o
@end example
@end quotation
-The first line can be interpreted as follows: the main unit which is
+You should interpret the first line as follows: the main unit, which is
contained in
-object file @code{demo1.o} is demo1, whose main source is in
+object file @code{demo1.o}, is demo1, whose main source is in
@code{demo1.adb}. Furthermore, the version of the source used for the
compilation of demo1 has been modified (DIF). Each source file has a status
qualifier which can be:
@@ -17916,9 +17901,9 @@ specified unit corresponds exactly to the actual source file.
The version of the source file used for the compilation of the
specified unit differs from the actual source file but not enough to
-require recompilation. If you use gnatmake with the option
-@code{-m} (minimal recompilation), a file marked
-MOK will not be recompiled.
+require recompilation (e.g., only comments have been changed). If
+you run @code{gnatmake} with the option @code{-m} (minimal
+recompilation), it will not recompile a file marked MOK.
@item `DIF (modified)'
@@ -17941,7 +17926,7 @@ version of the same source that has been modified.
@subsection Switches for @code{gnatls}
-@code{gnatls} recognizes the following switches:
+You can specify the following switches to @code{gnatls}:
@geindex --version (gnatls)
@@ -17950,7 +17935,7 @@ version of the same source that has been modified.
@item @code{--version}
-Display copyright and version, then exit disregarding all other options.
+Display copyright and version, then exit, disregarding all other options.
@end table
@geindex --help (gnatls)
@@ -17960,8 +17945,8 @@ Display copyright and version, then exit disregarding all other options.
@item @code{--help}
-If @code{--version} was not used, display usage, then exit disregarding
-all other options.
+If @code{--version} was not specified, display usage, then exit,
+disregarding all other options.
@end table
@geindex -a (gnatls)
@@ -17982,7 +17967,7 @@ Especially useful with @code{-d}.
@item @code{-d}
-List sources from which specified units depend on.
+List sources that specified units depend on.
@end table
@geindex -h (gnatls)
@@ -18032,10 +18017,10 @@ Only output information about compilation units.
@item @code{-files=`file'}
-Take as arguments the files listed in text file @code{file}.
-Text file @code{file} may contain empty lines that are ignored.
-Each nonempty line should contain the name of an existing file.
-Several such switches may be specified simultaneously.
+Take as arguments the files listed in text file @code{file}, which may
+contain empty lines that are ignored. Each nonempty line should
+contain the name of an existing file. Several such switches may be
+specified on the same command.
@end table
@geindex -aO (gnatls)
@@ -18051,8 +18036,8 @@ Several such switches may be specified simultaneously.
@item @code{-aO`dir'}, @code{-aI`dir'}, @code{-I`dir'}, @code{-I-}, @code{-nostdinc}
-Source path manipulation. Same meaning as the equivalent @code{gnatmake}
-flags (@ref{d0,,Switches for gnatmake}).
+Source path manipulation. It has the same meaning as the equivalent
+@code{gnatmake} switches (@ref{d0,,Switches for gnatmake}).
@end table
@geindex -aP (gnatls)
@@ -18072,8 +18057,9 @@ Add @code{dir} at the beginning of the project search dir.
@item @code{--RTS=`rts-path'}
-Specifies the default location of the runtime library. Same meaning as the
-equivalent @code{gnatmake} flag (@ref{d0,,Switches for gnatmake}).
+Specifies the default location of the runtime library. It has the
+same meaning as the equivalent @code{gnatmake} switch
+(@ref{d0,,Switches for gnatmake}).
@end table
@geindex -v (gnatls)
@@ -18083,7 +18069,7 @@ equivalent @code{gnatmake} flag (@ref{d0,,Switches for gnatmake}).
@item @code{-v}
-Verbose mode. Output the complete source, object and project paths. Do not use
+Verbose mode. Output the complete source, object and project paths. Don’t use
the default column layout but instead use long format giving as much as
information possible on each requested units, including special
characteristics such as:
@@ -18123,8 +18109,8 @@ by the user.
@subsection Example of @code{gnatls} Usage
-Example of using the verbose switch. Note how the source and
-object paths are affected by the -I switch.
+Here’s an example of using the verbose switch. Note how the source and
+object paths are affected by the @code{-I} switch.
@quotation
@@ -18157,9 +18143,9 @@ Project Search Path:
@end example
@end quotation
-The following is an example of use of the dependency list.
-Note the use of the -s switch
-which gives a straight list of source files. This can be useful for
+Here’s an example of use of the dependency list.
+Note the use of the @code{-s} switch,
+which gives a simple list of source files. You may find this useful for
building specialized scripts.
@quotation
@@ -18256,21 +18242,21 @@ This chapter covers several topics:
This section discusses how to debug Ada programs.
-An incorrect Ada program may be handled in three ways by the GNAT compiler:
+The GNAT compiler handles an incorrect Ada program in three ways:
@itemize *
@item
The illegality may be a violation of the static semantics of Ada. In
-that case GNAT diagnoses the constructs in the program that are illegal.
-It is then a straightforward matter for the user to modify those parts of
+that case, GNAT diagnoses the constructs in the program that are illegal.
+It’s then a straightforward matter for you to modify those parts of
the program.
@item
The illegality may be a violation of the dynamic semantics of Ada. In
that case the program compiles and executes, but may generate incorrect
-results, or may terminate abnormally with some exception.
+results or may terminate abnormally with some exception.
@item
When presented with a program that contains convoluted errors, GNAT
@@ -18307,56 +18293,57 @@ the incorrect user program.
@code{GDB} is a general purpose, platform-independent debugger that
-can be used to debug mixed-language programs compiled with @code{gcc},
+you can use to debug mixed-language programs, including compiled with @code{gcc},
and in particular is capable of debugging Ada programs compiled with
GNAT. The latest versions of @code{GDB} are Ada-aware and can handle
complex Ada data structures.
See @cite{Debugging with GDB},
for full details on the usage of @code{GDB}, including a section on
-its usage on programs. This manual should be consulted for full
+its usage on programs. That manual should be consulted for full
details. The section that follows is a brief introduction to the
philosophy and use of @code{GDB}.
-When GNAT programs are compiled, the compiler optionally writes debugging
+When programs are compiled, the compiler optionally writes debugging
information into the generated object file, including information on
-line numbers, and on declared types and variables. This information is
+line numbers and on declared types and variables. This information is
separate from the generated code. It makes the object files considerably
larger, but it does not add to the size of the actual executable that
-will be loaded into memory, and has no impact on run-time performance. The
+is loaded into memory and has no impact on run-time performance. The
generation of debug information is triggered by the use of the
@code{-g} switch in the @code{gcc} or @code{gnatmake} command
-used to carry out the compilations. It is important to emphasize that
-the use of these options does not change the generated code.
+you used to perform the compilations. It is important to emphasize that
+it’s a goal of GCC, and hence GNAT, that the use of this switch does
+not change the generated code.
-The debugging information is written in standard system formats that
+The compiler writes the debugging information in standard system formats that
are used by many tools, including debuggers and profilers. The format
of the information is typically designed to describe C types and
semantics, but GNAT implements a translation scheme which allows full
details about Ada types and variables to be encoded into these
standard C formats. Details of this encoding scheme may be found in
-the file exp_dbug.ads in the GNAT source distribution. However, the
-details of this encoding are, in general, of no interest to a user,
+the file @code{exp_dbug.ads} in the GNAT source distribution. However, the
+details of this encoding are, in most cases, of no interest to a user,
since @code{GDB} automatically performs the necessary decoding.
When a program is bound and linked, the debugging information is
-collected from the object files, and stored in the executable image of
+collected from the object files and stored in the executable image of
the program. Again, this process significantly increases the size of
-the generated executable file, but it does not increase the size of
-the executable program itself. Furthermore, if this program is run in
+the generated executable file, but does not increase the size of
+the executable program in memory. Furthermore, if this program is run in
the normal manner, it runs exactly as if the debug information were
-not present, and takes no more actual memory.
+not present and takes no more actual memory.
However, if the program is run under control of @code{GDB}, the
debugger is activated. The image of the program is loaded, at which
-point it is ready to run. If a run command is given, then the program
-will run exactly as it would have if @code{GDB} were not present. This
-is a crucial part of the @code{GDB} design philosophy. @code{GDB} is
+point it is ready to run. If you give a run command, the program
+runs exactly as it would have if @code{GDB} were not present. This
+is a crucial part of the @code{GDB} design philosophy: @code{GDB} is
entirely non-intrusive until a breakpoint is encountered. If no
-breakpoint is ever hit, the program will run exactly as it would if no
+breakpoint is ever hit, the program runs exactly as it would if no
debugger were present. When a breakpoint is hit, @code{GDB} accesses
the debugging information and can respond to user commands to inspect
-variables, and more generally to report on the state of execution.
+variables and more generally to report on the state of execution.
@node Running GDB,Introduction to GDB Commands,The GNAT Debugger GDB,Running and Debugging Ada Programs
@anchor{gnat_ugn/gnat_and_program_execution id4}@anchor{153}@anchor{gnat_ugn/gnat_and_program_execution running-gdb}@anchor{154}
@@ -18365,9 +18352,9 @@ variables, and more generally to report on the state of execution.
This section describes how to initiate the debugger.
-The debugger can be launched from a @code{GNAT Studio} menu or
+You can launch the debugger from a @code{GNAT Studio} menu or
directly from the command line. The description below covers the latter use.
-All the commands shown can be used in the @code{GNAT Studio} debug console window,
+You can use all the commands shown in the @code{GNAT Studio} debug console window,
but there are usually more GUI-based ways to achieve the same effect.
The command to run @code{GDB} is
@@ -18383,7 +18370,7 @@ where @code{program} is the name of the executable file. This
activates the debugger and results in a prompt for debugger commands.
The simplest command is simply @code{run}, which causes the program to run
exactly as if the debugger were not present. The following section
-describes some of the additional commands that can be given to @code{GDB}.
+describes some of the additional commands that you can give to @code{GDB}.
@node Introduction to GDB Commands,Using Ada Expressions,Running GDB,Running and Debugging Ada Programs
@anchor{gnat_ugn/gnat_and_program_execution id5}@anchor{155}@anchor{gnat_ugn/gnat_and_program_execution introduction-to-gdb-commands}@anchor{156}
@@ -18395,10 +18382,10 @@ See @cite{Debugging with GDB} for extensive documentation on the use
of these commands, together with examples of their use. Furthermore,
the command `help' invoked from within GDB activates a simple help
facility which summarizes the available commands and their options.
-In this section we summarize a few of the most commonly
+In this section, we summarize a few of the most commonly
used commands to give an idea of what @code{GDB} is about. You should create
a simple program with debugging information and experiment with the use of
-these @code{GDB} commands on the program as you read through the
+these @code{GDB} commands on that program as you read through the
following section.
@@ -18410,10 +18397,10 @@ following section.
@item @code{set args @var{arguments}}
-The `arguments' list above is a list of arguments to be passed to
-the program on a subsequent run command, just as though the arguments
-had been entered on a normal invocation of the program. The @code{set args}
-command is not needed if the program does not require arguments.
+`arguments' is a list of arguments to be passed to the program on
+a subsequent run command, just as though the arguments had been
+entered on a normal invocation of the program. You do not need the
+@code{set args} command if the program does not require arguments.
@end table
@item
@@ -18426,7 +18413,9 @@ The @code{run} command causes execution of the program to start from
the beginning. If the program is already running, that is to say if
you are currently positioned at a breakpoint, then a prompt will ask
for confirmation that you want to abandon the current execution and
-restart.
+restart. You can also specify program arguments on this command and
+if you specify @code{run} with no arguments, the arguments used on
+the previous command will be used again.
@end table
@item
@@ -18435,17 +18424,17 @@ restart.
@item @code{breakpoint @var{location}}
-The breakpoint command sets a breakpoint, that is to say a point at which
+This command sets a breakpoint, that is to say a point at which
execution will halt and @code{GDB} will await further
-commands. `location' is
-either a line number within a file, given in the format @code{file:linenumber},
-or it is the name of a subprogram. If you request that a breakpoint be set on
-a subprogram that is overloaded, a prompt will ask you to specify on which of
-those subprograms you want to breakpoint. You can also
-specify that all of them should be breakpointed. If the program is run
-and execution encounters the breakpoint, then the program
-stops and @code{GDB} signals that the breakpoint was encountered by
-printing the line of code before which the program is halted.
+commands. `location' is either a line number within a file, which
+you specify in the format @code{file:linenumber}, or the name of a
+subprogram. If you request a breakpoint be set on a subprogram
+that is overloaded, either a prompt will ask you to specify on
+which of those subprograms you want to breakpoint or a breakpoint
+will be set on all of them. If the program is run and execution
+encounters the breakpoint, the program stops and @code{GDB}
+signals that the breakpoint was encountered by printing the line
+of code before which the program is halted.
@end table
@item
@@ -18455,7 +18444,7 @@ printing the line of code before which the program is halted.
@item @code{catch exception @var{name}}
This command causes the program execution to stop whenever exception
-@code{name} is raised. If @code{name} is omitted, then the execution is
+@code{name} is raised. If you omit @code{name}, execution is
suspended when any exception is raised.
@end table
@@ -18465,7 +18454,7 @@ suspended when any exception is raised.
@item @code{print @var{expression}}
-This will print the value of the given expression. Most simple
+This prints the value of the given expression. Most
Ada expression formats are properly handled by @code{GDB}, so the expression
can contain function calls, variables, operators, and attribute references.
@end table
@@ -18476,7 +18465,7 @@ can contain function calls, variables, operators, and attribute references.
@item @code{continue}
-Continues execution following a breakpoint, until the next breakpoint or the
+Continues execution following a breakpoint until the next breakpoint or the
termination of the program.
@end table
@@ -18497,22 +18486,24 @@ the called subprogram.
@item @code{next}
-Executes a single line. If this line is a subprogram call, executes and
-returns from the call.
+Executes a single line. If this line is a subprogram call, the
+program executes that call and returns.
@end table
@item
+@code{list}
-@table @asis
-
-@item @code{list}
+@quotation
-Lists a few lines around the current source location. In practice, it
-is usually more convenient to have a separate edit window open with the
-relevant source file displayed. Successive applications of this command
-print subsequent lines. The command can be given an argument which is a
-line number, in which case it displays a few lines around the specified one.
-@end table
+Lists a few lines around the current source location. In practice,
+it is usually more convenient to have a separate edit window open
+with the relevant source file displayed. @code{emacs} has debugging
+modes that display both the relevant source and @code{GDB} commands
+and output. Successive applications of this command print
+subsequent lines. You can give this command an argument which is a
+line number, in which case it displays a few lines around the
+specified line.
+@end quotation
@item
@@ -18521,7 +18512,7 @@ line number, in which case it displays a few lines around the specified one.
@item @code{backtrace}
Displays a backtrace of the call chain. This command is typically
-used after a breakpoint has occurred, to examine the sequence of calls that
+used after a breakpoint has occurred to examine the sequence of calls that
leads to the current breakpoint. The display includes one line for each
activation record (frame) corresponding to an active subprogram.
@end table
@@ -18533,8 +18524,8 @@ activation record (frame) corresponding to an active subprogram.
@item @code{up}
At a breakpoint, @code{GDB} can display the values of variables local
-to the current frame. The command @code{up} can be used to
-examine the contents of other active frames, by moving the focus up
+to the current frame. You can use the command @code{up} to
+examine the contents of other active frames by moving the focus up
the stack, that is to say from callee to caller, one frame at a time.
@end table
@@ -18565,7 +18556,7 @@ of the current breakpoint, that is to say the top of the call stack.
@item @code{kill}
Kills the child process in which the program is running under GDB.
-This may be useful for several purposes:
+You may find this useful for several purposes:
@itemize *
@@ -18575,7 +18566,7 @@ It allows you to recompile and relink your program, since on many systems
you cannot regenerate an executable file while it is running in a process.
@item
-You can run your program outside the debugger, on systems that do not
+You can run your program outside the debugger on systems that do not
permit executing a program outside GDB while breakpoints are set
within GDB.
@@ -18585,13 +18576,15 @@ It allows you to debug a core dump rather than a running process.
@end table
@end itemize
-The above list is a very short introduction to the commands that
+The above is a very short introduction to the commands that
@code{GDB} provides. Important additional capabilities, including conditional
breakpoints, the ability to execute command sequences on a breakpoint,
the ability to debug at the machine instruction level and many other
features are described in detail in @cite{Debugging with GDB}.
Note that most commands can be abbreviated
-(for example, c for continue, bt for backtrace).
+(for example, “c” for @code{continue} and “bt” for @code{backtrace}) and only enough
+characters need be typed to disambiguate the command (e.g., “br” for
+@code{breakpoint}).
@node Using Ada Expressions,Calling User-Defined Subprograms,Introduction to GDB Commands,Running and Debugging Ada Programs
@anchor{gnat_ugn/gnat_and_program_execution id6}@anchor{157}@anchor{gnat_ugn/gnat_and_program_execution using-ada-expressions}@anchor{158}
@@ -18600,7 +18593,7 @@ Note that most commands can be abbreviated
@geindex Ada expressions (in gdb)
-@code{GDB} supports a fairly large subset of Ada expression syntax, with some
+@code{GDB} supports a very large subset of Ada expression syntax, with some
extensions. The philosophy behind the design of this subset is
@quotation
@@ -18609,17 +18602,17 @@ extensions. The philosophy behind the design of this subset is
@itemize *
@item
-That @code{GDB} should provide basic literals and access to operations for
+@code{GDB} should provide basic literals and access to operations for
arithmetic, dereferencing, field selection, indexing, and subprogram calls,
leaving more sophisticated computations to subprograms written into the
program (which therefore may be called from @code{GDB}).
@item
-That type safety and strict adherence to Ada language restrictions
+Type safety and strict adherence to Ada language restrictions
are not particularly relevant in a debugging context.
@item
-That brevity is important to the @code{GDB} user.
+Brevity is important to the @code{GDB} user.
@end itemize
@end quotation
@@ -18637,7 +18630,7 @@ For details on the supported Ada syntax, see @cite{Debugging with GDB}.
An important capability of @code{GDB} is the ability to call user-defined
-subprograms while debugging. This is achieved simply by entering
+subprograms while debugging. You do this by simply entering
a subprogram call statement in the form:
@quotation
@@ -18647,22 +18640,22 @@ call subprogram-name (parameters)
@end example
@end quotation
-The keyword @code{call} can be omitted in the normal case where the
+You can omit the keyword @code{call} in the normal case where the
@code{subprogram-name} does not coincide with any of the predefined
@code{GDB} commands.
The effect is to invoke the given subprogram, passing it the
-list of parameters that is supplied. The parameters can be expressions and
+list of parameters that is supplied. The parameters you specify can be expressions and
can include variables from the program being debugged. The
subprogram must be defined
-at the library level within your program, and @code{GDB} will call the
+at the library level within your program and @code{GDB} will call the
subprogram within the environment of your program execution (which
means that the subprogram is free to access or even modify variables
within your program).
-The most important use of this facility is in allowing the inclusion of
+The most important use of this facility that you can include
debugging routines that are tailored to particular data structures
-in your program. Such debugging routines can be written to provide a suitably
+in your program. You can write such debugging routines to provide a suitably
high-level description of an abstract type, rather than a low-level dump
of its physical layout. After all, the standard
@code{GDB print} command only knows the physical layout of your
@@ -18674,21 +18667,21 @@ the contents of the tree nodes used to represent the program internally.
But tree nodes are represented simply by an integer value (which in turn
is an index into a table of nodes).
Using the @code{print} command on a tree node would simply print this integer
-value, which is not very useful. But the PN routine (defined in file
-treepr.adb in the GNAT sources) takes a tree node as input, and displays
+value, which is not very useful. But the @code{PN} routine (defined in file
+@code{treepr.adb} in the GNAT sources) takes a tree node as input and displays
a useful high level representation of the tree node, which includes the
-syntactic category of the node, its position in the source, the integers
-that denote descendant nodes and parent node, as well as varied
+syntactic category of the node, its position in the source,
+the descendant nodes and parent node, as well as lots of
semantic information. To study this example in more detail, you might want to
-look at the body of the PN procedure in the stated file.
+look at the body of the @code{PN} procedure in the above file.
-Another useful application of this capability is to deal with situations of
+Another useful application of this capability is to deal with situations where
complex data which are not handled suitably by GDB. For example, if you specify
Convention Fortran for a multi-dimensional array, GDB does not know that
the ordering of array elements has been switched and will not properly
address the array elements. In such a case, instead of trying to print the
elements directly from GDB, you can write a callable procedure that prints
-the elements in the desired format.
+the elements in the format you desire.
@node Using the next Command in a Function,Stopping When Ada Exceptions Are Raised,Calling User-Defined Subprograms,Running and Debugging Ada Programs
@anchor{gnat_ugn/gnat_and_program_execution id8}@anchor{15b}@anchor{gnat_ugn/gnat_and_program_execution using-the-next-command-in-a-function}@anchor{15c}
@@ -18701,7 +18694,7 @@ arises in the case of a @code{return} statement.
Part of the code for a return statement is the ‘epilogue’ of the function.
This is the code that returns to the caller. There is only one copy of
-this epilogue code, and it is typically associated with the last return
+this epilogue code and it is typically associated with the last return
statement in the function if there is more than one return. In some
implementations, this epilogue is associated with the first statement
of the function.
@@ -18797,8 +18790,8 @@ This command shows a list of current Ada tasks, as in the following example:
* 4 80ae800 3 80b8000 15 Running c
@end example
-In this listing, the asterisk before the first task indicates it to be the
-currently running task. The first column lists the task ID that is used
+In this listing, the asterisk before the first task indicates it’s
+currently running task. The first column lists the task ID used
to refer to tasks in the following commands.
@end table
@end itemize
@@ -18817,12 +18810,12 @@ These commands are like the @code{break ... thread ...}.
`linespec' specifies source lines.
Use the qualifier @code{task @var{taskid}} with a breakpoint command
-to specify that you only want @code{GDB} to stop the program when a
+to specify that you only want @code{GDB} to stop the program when that
particular Ada task reaches this breakpoint. `taskid' is one of the
numeric task identifiers assigned by @code{GDB}, shown in the first
column of the @code{info tasks} display.
-If you do not specify @code{task @var{taskid}} when you set a
+If you don’t specify @code{task @var{taskid}} when you set a
breakpoint, the breakpoint applies to `all' tasks of your
program.
@@ -18843,14 +18836,14 @@ breakpoint condition (before the @code{if}).
@quotation
This command allows switching to the task referred by `taskno'. In
-particular, this allows browsing of the backtrace of the specified
-task. It is advisable to switch back to the original task before
-continuing execution otherwise the scheduling of the program may be
-perturbed.
+particular, it allows browsing the backtrace of the specified
+task. You should switch back to the original task before
+continuing execution; otherwise the scheduling of the program may be
+disturbed.
@end quotation
@end itemize
-For more detailed information on the tasking support,
+For more detailed information on tasking support,
see @cite{Debugging with GDB}.
@geindex Debugging Generic Units
@@ -18862,13 +18855,14 @@ see @cite{Debugging with GDB}.
@subsection Debugging Generic Units
-GNAT always uses code expansion for generic instantiation. This means that
-each time an instantiation occurs, a complete copy of the origina