C++ P0482R6 char8_t: declare std::c8rtomb and std::mbrtoc8 if provided by the C library
Commit Message
This patch completes implementation of the C++20 proposal P0482R6 [1] by
adding declarations of std::c8rtomb() and std::mbrtoc8() in <cuchar> if
provided by the C library in <uchar.h>.
This patch addresses feedback provided in response to a previous patch
submission [2].
Autoconf changes determine if the C library declares c8rtomb and mbrtoc8
at global scope when uchar.h is included and compiled with either
-fchar8_t or -std=c++20. New _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T
and _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20 configuration macros
reflect the probe results. The <cuchar> header declares these functions
in the std namespace only if available and the _GLIBCXX_USE_CHAR8_T
configuration macro is defined (by default it is defined if the C++20
__cpp_char8_t feature test macro is defined)
Patches to glibc to implement c8rtomb and mbrtoc8 have been submitted [3].
New tests validate the presence of these declarations. The tests pass
trivially if the C library does not provide these functions. Otherwise
they ensure that the functions are declared when <cuchar> is included
and either -fchar8_t or -std=c++20 is enabled.
Tested on Linux x86_64.
libstdc++-v3/ChangeLog:
2022-01-07 Tom Honermann <tom@honermann.net>
* acinclude.m4 Define config macros if uchar.h provides
c8rtomb() and mbrtoc8().
* config.h.in: Re-generate.
* configure: Re-generate.
* include/c_compatibility/uchar.h: Declare ::c8rtomb and
::mbrtoc8.
* include/c_global/cuchar: Declare std::c8rtomb and
std::mbrtoc8.
* include/c_std/cuchar: Declare std::c8rtomb and std::mbrtoc8.
* testsuite/21_strings/headers/cuchar/functions_std_cxx20.cc:
New test.
* testsuite/21_strings/headers/cuchar/functions_std_fchar8_t.cc:
New test.
Tom.
[1]: WG21 P0482R6
"char8_t: A type for UTF-8 characters and strings (Revision 6)"
https://wg21.link/p0482r6
[2]: [PATCH] C++ P0482R6 char8_t: declare std::c8rtomb and std::mbrtoc8
if provided by the C library
https://gcc.gnu.org/pipermail/libstdc++/2021-June/052685.html
[3]: "C++20 P0482R6 and C2X N2653"
[Patch 0/3]:
https://sourceware.org/pipermail/libc-alpha/2022-January/135061.html
[Patch 1/3]:
https://sourceware.org/pipermail/libc-alpha/2022-January/135062.html
[Patch 2/3]:
https://sourceware.org/pipermail/libc-alpha/2022-January/135063.html
[Patch 3/3]:
https://sourceware.org/pipermail/libc-alpha/2022-January/135064.html
Tom.
Comments
On Sat, 8 Jan 2022 at 00:42, Tom Honermann via Libstdc++ <
libstdc++@gcc.gnu.org> wrote:
> This patch completes implementation of the C++20 proposal P0482R6 [1] by
> adding declarations of std::c8rtomb() and std::mbrtoc8() in <cuchar> if
> provided by the C library in <uchar.h>.
>
> This patch addresses feedback provided in response to a previous patch
> submission [2].
>
> Autoconf changes determine if the C library declares c8rtomb and mbrtoc8
> at global scope when uchar.h is included and compiled with either
> -fchar8_t or -std=c++20. New _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T
> and _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20 configuration macros
> reflect the probe results. The <cuchar> header declares these functions
> in the std namespace only if available and the _GLIBCXX_USE_CHAR8_T
> configuration macro is defined (by default it is defined if the C++20
> __cpp_char8_t feature test macro is defined)
>
> Patches to glibc to implement c8rtomb and mbrtoc8 have been submitted [3].
>
> New tests validate the presence of these declarations. The tests pass
> trivially if the C library does not provide these functions. Otherwise
> they ensure that the functions are declared when <cuchar> is included
> and either -fchar8_t or -std=c++20 is enabled.
>
> Tested on Linux x86_64.
>
> libstdc++-v3/ChangeLog:
>
> 2022-01-07 Tom Honermann <tom@honermann.net>
>
> * acinclude.m4 Define config macros if uchar.h provides
> c8rtomb() and mbrtoc8().
> * config.h.in: Re-generate.
> * configure: Re-generate.
> * include/c_compatibility/uchar.h: Declare ::c8rtomb and
> ::mbrtoc8.
> * include/c_global/cuchar: Declare std::c8rtomb and
> std::mbrtoc8.
> * include/c_std/cuchar: Declare std::c8rtomb and std::mbrtoc8.
> * testsuite/21_strings/headers/cuchar/functions_std_cxx20.cc:
> New test.
> * testsuite/21_strings/headers/cuchar/functions_std_fchar8_t.cc:
> New test.
>
Thanks, Tom, this looks good and I'll get it committed for GCC 12.
My only concern is that the new tests depend on an internal macro:
+#if _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20
+ using std::mbrtoc8;
+ using std::c8rtomb;
I prefer if tests are written as "user code" when possible, and not using
our internal macros. That isn't always possible, and in this case would
require adding new effective-target keyword to testsuite/lib/libstdc++.exp
just for use in these two tests. I don't think we should bother with that.
I suppose strictly speaking we should not define __cpp_lib_char8_t unless
these two functions are present in libc. But I'm not sure we want to change
that now either.
On 1/10/22 8:23 AM, Jonathan Wakely wrote:
>
>
> On Sat, 8 Jan 2022 at 00:42, Tom Honermann via Libstdc++
> <libstdc++@gcc.gnu.org <mailto:libstdc%2B%2B@gcc.gnu.org>> wrote:
>
> This patch completes implementation of the C++20 proposal P0482R6
> [1] by
> adding declarations of std::c8rtomb() and std::mbrtoc8() in
> <cuchar> if
> provided by the C library in <uchar.h>.
>
> This patch addresses feedback provided in response to a previous
> patch
> submission [2].
>
> Autoconf changes determine if the C library declares c8rtomb and
> mbrtoc8
> at global scope when uchar.h is included and compiled with either
> -fchar8_t or -std=c++20. New
> _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T
> and _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20 configuration macros
> reflect the probe results. The <cuchar> header declares these
> functions
> in the std namespace only if available and the _GLIBCXX_USE_CHAR8_T
> configuration macro is defined (by default it is defined if the C++20
> __cpp_char8_t feature test macro is defined)
>
> Patches to glibc to implement c8rtomb and mbrtoc8 have been
> submitted [3].
>
> New tests validate the presence of these declarations. The tests pass
> trivially if the C library does not provide these functions.
> Otherwise
> they ensure that the functions are declared when <cuchar> is included
> and either -fchar8_t or -std=c++20 is enabled.
>
> Tested on Linux x86_64.
>
> libstdc++-v3/ChangeLog:
>
> 2022-01-07 Tom Honermann <tom@honermann.net
> <mailto:tom@honermann.net>>
>
> * acinclude.m4 Define config macros if uchar.h provides
> c8rtomb() and mbrtoc8().
> * config.h.in <http://config.h.in>: Re-generate.
> * configure: Re-generate.
> * include/c_compatibility/uchar.h: Declare ::c8rtomb and
> ::mbrtoc8.
> * include/c_global/cuchar: Declare std::c8rtomb and
> std::mbrtoc8.
> * include/c_std/cuchar: Declare std::c8rtomb and std::mbrtoc8.
> * testsuite/21_strings/headers/cuchar/functions_std_cxx20.cc:
> New test.
> *
> testsuite/21_strings/headers/cuchar/functions_std_fchar8_t.cc:
> New test.
>
>
>
> Thanks, Tom, this looks good and I'll get it committed for GCC 12.
Thank you!
>
> My only concern is that the new tests depend on an internal macro:
>
> +#if _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20
> + using std::mbrtoc8;
> + using std::c8rtomb;
>
> I prefer if tests are written as "user code" when possible, and not
> using our internal macros. That isn't always possible, and in this
> case would require adding new effective-target keyword to
> testsuite/lib/libstdc++.exp just for use in these two tests. I don't
> think we should bother with that.
I went with this approach solely due to my unfamiliarity with the test
system. I knew there should be a way to conditionally make the test
"pass" as unsupported or as an expected failure, but didn't know how to
go about implementing that. I don't mind following up with an additional
patch if such a change is desirable. I took a look at
testsuite/lib/libstdc++.exp and it looks like it may be pretty straight
forward to add effective-target support. It would probably be a good
learning experience for me. I'll prototype and report back.
>
> I suppose strictly speaking we should not define __cpp_lib_char8_t
> unless these two functions are present in libc. But I'm not sure we
> want to change that now either.
All of libstdc++, libc++, and MS STL have been defining
__cpp_lib_char8_t despite the absence of these functions, so yeah, I
don't think we want to change that.
Tom.
On Mon, 10 Jan 2022 at 21:24, Tom Honermann via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
>
> On 1/10/22 8:23 AM, Jonathan Wakely wrote:
> >
> >
> > On Sat, 8 Jan 2022 at 00:42, Tom Honermann via Libstdc++
> > <libstdc++@gcc.gnu.org <mailto:libstdc%2B%2B@gcc.gnu.org>> wrote:
> >
> > This patch completes implementation of the C++20 proposal P0482R6
> > [1] by
> > adding declarations of std::c8rtomb() and std::mbrtoc8() in
> > <cuchar> if
> > provided by the C library in <uchar.h>.
> >
> > This patch addresses feedback provided in response to a previous
> > patch
> > submission [2].
> >
> > Autoconf changes determine if the C library declares c8rtomb and
> > mbrtoc8
> > at global scope when uchar.h is included and compiled with either
> > -fchar8_t or -std=c++20. New
> > _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T
> > and _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20 configuration macros
> > reflect the probe results. The <cuchar> header declares these
> > functions
> > in the std namespace only if available and the _GLIBCXX_USE_CHAR8_T
> > configuration macro is defined (by default it is defined if the C++20
> > __cpp_char8_t feature test macro is defined)
> >
> > Patches to glibc to implement c8rtomb and mbrtoc8 have been
> > submitted [3].
> >
> > New tests validate the presence of these declarations. The tests pass
> > trivially if the C library does not provide these functions.
> > Otherwise
> > they ensure that the functions are declared when <cuchar> is included
> > and either -fchar8_t or -std=c++20 is enabled.
> >
> > Tested on Linux x86_64.
> >
> > libstdc++-v3/ChangeLog:
> >
> > 2022-01-07 Tom Honermann <tom@honermann.net
> > <mailto:tom@honermann.net>>
> >
> > * acinclude.m4 Define config macros if uchar.h provides
> > c8rtomb() and mbrtoc8().
> > * config.h.in <http://config.h.in>: Re-generate.
> > * configure: Re-generate.
> > * include/c_compatibility/uchar.h: Declare ::c8rtomb and
> > ::mbrtoc8.
> > * include/c_global/cuchar: Declare std::c8rtomb and
> > std::mbrtoc8.
> > * include/c_std/cuchar: Declare std::c8rtomb and std::mbrtoc8.
> > * testsuite/21_strings/headers/cuchar/functions_std_cxx20.cc:
> > New test.
> > *
> > testsuite/21_strings/headers/cuchar/functions_std_fchar8_t.cc:
> > New test.
> >
> >
> >
> > Thanks, Tom, this looks good and I'll get it committed for GCC 12.
> Thank you!
> >
> > My only concern is that the new tests depend on an internal macro:
> >
> > +#if _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20
> > + using std::mbrtoc8;
> > + using std::c8rtomb;
> >
> > I prefer if tests are written as "user code" when possible, and not
> > using our internal macros. That isn't always possible, and in this
> > case would require adding new effective-target keyword to
> > testsuite/lib/libstdc++.exp just for use in these two tests. I don't
> > think we should bother with that.
> I went with this approach solely due to my unfamiliarity with the test
> system. I knew there should be a way to conditionally make the test
> "pass" as unsupported or as an expected failure, but didn't know how to
> go about implementing that. I don't mind following up with an additional
> patch if such a change is desirable. I took a look at
> testsuite/lib/libstdc++.exp and it looks like it may be pretty straight
> forward to add effective-target support. It would probably be a good
> learning experience for me. I'll prototype and report back.
Yes, it's very easy to do. Take a look at the
check_effective_target_blah procs in that file, especially the later
ones that use v3_check_preprocessor_condition. You can use that to
define an effective target keyword for any preprocessor condition
(such as the new macros you're adding).
Then the test can do:
// { dg-do compile { target blah } }
which will make it UNSUPPORTED if the effective target proc doesn't return true.
See https://gcc.gnu.org/onlinedocs/gccint/Selectors.html#Selectors for
the docs on target selectors.
I'm just not sure it's worth adding a new keyword for just two tests.
> >
> > I suppose strictly speaking we should not define __cpp_lib_char8_t
> > unless these two functions are present in libc. But I'm not sure we
> > want to change that now either.
>
> All of libstdc++, libc++, and MS STL have been defining
> __cpp_lib_char8_t despite the absence of these functions, so yeah, I
> don't think we want to change that.
OK, thanks.
On 1/10/22 4:38 PM, Jonathan Wakely wrote:
> On Mon, 10 Jan 2022 at 21:24, Tom Honermann via Libstdc++
> <libstdc++@gcc.gnu.org> wrote:
>> On 1/10/22 8:23 AM, Jonathan Wakely wrote:
>>>
>>> On Sat, 8 Jan 2022 at 00:42, Tom Honermann via Libstdc++
>>> <libstdc++@gcc.gnu.org <mailto:libstdc%2B%2B@gcc.gnu.org>> wrote:
>>>
>>> This patch completes implementation of the C++20 proposal P0482R6
>>> [1] by
>>> adding declarations of std::c8rtomb() and std::mbrtoc8() in
>>> <cuchar> if
>>> provided by the C library in <uchar.h>.
>>>
>>> This patch addresses feedback provided in response to a previous
>>> patch
>>> submission [2].
>>>
>>> Autoconf changes determine if the C library declares c8rtomb and
>>> mbrtoc8
>>> at global scope when uchar.h is included and compiled with either
>>> -fchar8_t or -std=c++20. New
>>> _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T
>>> and _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20 configuration macros
>>> reflect the probe results. The <cuchar> header declares these
>>> functions
>>> in the std namespace only if available and the _GLIBCXX_USE_CHAR8_T
>>> configuration macro is defined (by default it is defined if the C++20
>>> __cpp_char8_t feature test macro is defined)
>>>
>>> Patches to glibc to implement c8rtomb and mbrtoc8 have been
>>> submitted [3].
>>>
>>> New tests validate the presence of these declarations. The tests pass
>>> trivially if the C library does not provide these functions.
>>> Otherwise
>>> they ensure that the functions are declared when <cuchar> is included
>>> and either -fchar8_t or -std=c++20 is enabled.
>>>
>>> Tested on Linux x86_64.
>>>
>>> libstdc++-v3/ChangeLog:
>>>
>>> 2022-01-07 Tom Honermann <tom@honermann.net
>>> <mailto:tom@honermann.net>>
>>>
>>> * acinclude.m4 Define config macros if uchar.h provides
>>> c8rtomb() and mbrtoc8().
>>> * config.h.in <http://config.h.in>: Re-generate.
>>> * configure: Re-generate.
>>> * include/c_compatibility/uchar.h: Declare ::c8rtomb and
>>> ::mbrtoc8.
>>> * include/c_global/cuchar: Declare std::c8rtomb and
>>> std::mbrtoc8.
>>> * include/c_std/cuchar: Declare std::c8rtomb and std::mbrtoc8.
>>> * testsuite/21_strings/headers/cuchar/functions_std_cxx20.cc:
>>> New test.
>>> *
>>> testsuite/21_strings/headers/cuchar/functions_std_fchar8_t.cc:
>>> New test.
>>>
>>>
>>>
>>> Thanks, Tom, this looks good and I'll get it committed for GCC 12.
>> Thank you!
>>> My only concern is that the new tests depend on an internal macro:
>>>
>>> +#if _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20
>>> + using std::mbrtoc8;
>>> + using std::c8rtomb;
>>>
>>> I prefer if tests are written as "user code" when possible, and not
>>> using our internal macros. That isn't always possible, and in this
>>> case would require adding new effective-target keyword to
>>> testsuite/lib/libstdc++.exp just for use in these two tests. I don't
>>> think we should bother with that.
>> I went with this approach solely due to my unfamiliarity with the test
>> system. I knew there should be a way to conditionally make the test
>> "pass" as unsupported or as an expected failure, but didn't know how to
>> go about implementing that. I don't mind following up with an additional
>> patch if such a change is desirable. I took a look at
>> testsuite/lib/libstdc++.exp and it looks like it may be pretty straight
>> forward to add effective-target support. It would probably be a good
>> learning experience for me. I'll prototype and report back.
> Yes, it's very easy to do. Take a look at the
> check_effective_target_blah procs in that file, especially the later
> ones that use v3_check_preprocessor_condition. You can use that to
> define an effective target keyword for any preprocessor condition
> (such as the new macros you're adding).
>
> Then the test can do:
> // { dg-do compile { target blah } }
> which will make it UNSUPPORTED if the effective target proc doesn't return true.
> See https://gcc.gnu.org/onlinedocs/gccint/Selectors.html#Selectors for
> the docs on target selectors.
>
> I'm just not sure it's worth adding a new keyword for just two tests.
Thank you for the implementation direction; this was quite easy!
Patch attached (to be applied after the original one).
libstdc++-v3/ChangeLog:
2022-01-11 Tom Honermann <tom@honermann.net>
* testsuite/21_strings/headers/cuchar/functions_std_cxx20.cc:
Modify to use new c8rtomb_mbrtoc8_cxx20 effective target.
* testsuite/21_strings/headers/cuchar/functions_std_fchar8_t.cc:
Modify to use new c8rtomb_mbrtoc8_fchar8_t effective target.
* testsuite/lib/libstdc++.exp: Add new effective targets.
If you decide that the new keywords aren't worth adding, no worries; my
feelings won't be hurt :)
Tom.
commit 3d40bc9bf5c79343ea5a6cc355539542f4b56c9b
Author: Tom Honermann <tom@honermann.net>
Date: Sat Jan 1 17:26:31 2022 -0500
P0482R6 char8_t: declare std::c8rtomb and std::mbrtoc8 if provided by the C library.
This change completes implementation of the C++20 proposal P0482R6 by
adding declarations of std::c8rtomb() and std::mbrtoc8() if provided
by the C library.
Autoconf changes determine if the C library declares c8rtomb and mbrtoc8
at global scope when uchar.h is included and compiled with either -fchar8_t
or -std=c++20 enabled; new _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T and
_GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20 configuration macros are defined
accordingly. The <cuchar> header declares these functions in the std
namespace only if available and the _GLIBCXX_USE_CHAR8_T configuration
macro is defined (by default it is defined if the C++20 __cpp_char8_t
feature test macro is defined).
New tests validate the presence of these declarations. The tests pass
trivially if the C library does not provide these functions. Otherwise they
ensure that the functions are declared when <cuchar> is included and
either -fchar8_t or -std=c++20 is enabled.
@@ -2039,6 +2039,50 @@ AC_DEFUN([GLIBCXX_CHECK_UCHAR_H], [
namespace std in <cuchar>.])
fi
+ CXXFLAGS="$CXXFLAGS -fchar8_t"
+ if test x"$ac_has_uchar_h" = x"yes"; then
+ AC_MSG_CHECKING([for c8rtomb and mbrtoc8 in <uchar.h> with -fchar8_t])
+ AC_TRY_COMPILE([#include <uchar.h>
+ namespace test
+ {
+ using ::c8rtomb;
+ using ::mbrtoc8;
+ }
+ ],
+ [], [ac_uchar_c8rtomb_mbrtoc8_fchar8_t=yes],
+ [ac_uchar_c8rtomb_mbrtoc8_fchar8_t=no])
+ else
+ ac_uchar_c8rtomb_mbrtoc8_fchar8_t=no
+ fi
+ AC_MSG_RESULT($ac_uchar_c8rtomb_mbrtoc8_fchar8_t)
+ if test x"$ac_uchar_c8rtomb_mbrtoc8_fchar8_t" = x"yes"; then
+ AC_DEFINE(_GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T, 1,
+ [Define if c8rtomb and mbrtoc8 functions in <uchar.h> should be
+ imported into namespace std in <cuchar> for -fchar8_t.])
+ fi
+
+ CXXFLAGS="$CXXFLAGS -std=c++20"
+ if test x"$ac_has_uchar_h" = x"yes"; then
+ AC_MSG_CHECKING([for c8rtomb and mbrtoc8 in <uchar.h> with -std=c++20])
+ AC_TRY_COMPILE([#include <uchar.h>
+ namespace test
+ {
+ using ::c8rtomb;
+ using ::mbrtoc8;
+ }
+ ],
+ [], [ac_uchar_c8rtomb_mbrtoc8_cxx20=yes],
+ [ac_uchar_c8rtomb_mbrtoc8_cxx20=no])
+ else
+ ac_uchar_c8rtomb_mbrtoc8_cxx20=no
+ fi
+ AC_MSG_RESULT($ac_uchar_c8rtomb_mbrtoc8_cxx20)
+ if test x"$ac_uchar_c8rtomb_mbrtoc8_cxx20" = x"yes"; then
+ AC_DEFINE(_GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20, 1,
+ [Define if c8rtomb and mbrtoc8 functions in <uchar.h> should be
+ imported into namespace std in <cuchar> for C++20.])
+ fi
+
CXXFLAGS="$ac_save_CXXFLAGS"
AC_LANG_RESTORE
])
@@ -1000,6 +1000,14 @@
/* Define if obsolescent tmpnam is available in <stdio.h>. */
#undef _GLIBCXX_USE_TMPNAM
+/* Define if c8rtomb and std functions in <uchar.h> should be
+ imported into namespace std in <cuchar> for -fchar8_t. */
+#undef _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T
+
+/* Define if c8rtomb and std functions in <uchar.h> should be
+ imported into namespace std in <cuchar> for C++20. */
+#undef _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20
+
/* Define if utime is available in <utime.h>. */
#undef _GLIBCXX_USE_UTIME
@@ -19130,6 +19130,82 @@ $as_echo "#define _GLIBCXX_USE_C11_UCHAR_CXX11 1" >>confdefs.h
fi
+ CXXFLAGS="$CXXFLAGS -fchar8_t"
+ if test x"$ac_has_uchar_h" = x"yes"; then
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking for c8rtomb and mbrtoc8 in <uchar.h> with -fchar8_t" >&5
+$as_echo_n "checking for c8rtomb and mbrtoc8 in <uchar.h> with -fchar8_t... " >&6; }
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+#include <uchar.h>
+ namespace test
+ {
+ using ::c8rtomb;
+ using ::mbrtoc8;
+ }
+
+int
+main ()
+{
+
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_cxx_try_compile "$LINENO"; then :
+ ac_uchar_c8rtomb_mbrtoc8_fchar8_t=yes
+else
+ ac_uchar_c8rtomb_mbrtoc8_fchar8_t=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ else
+ ac_uchar_c8rtomb_mbrtoc8_fchar8_t=no
+ fi
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_uchar_c8rtomb_mbrtoc8_fchar8_t" >&5
+$as_echo "$ac_uchar_c8rtomb_mbrtoc8_fchar8_t" >&6; }
+ if test x"$ac_uchar_c8rtomb_mbrtoc8_fchar8_t" = x"yes"; then
+
+$as_echo "#define _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T 1" >>confdefs.h
+
+ fi
+
+ CXXFLAGS="$CXXFLAGS -std=c++20"
+ if test x"$ac_has_uchar_h" = x"yes"; then
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking for c8rtomb and mbrtoc8 in <uchar.h> with -std=c++20" >&5
+$as_echo_n "checking for c8rtomb and mbrtoc8 in <uchar.h> with -std=c++20... " >&6; }
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+#include <uchar.h>
+ namespace test
+ {
+ using ::c8rtomb;
+ using ::mbrtoc8;
+ }
+
+int
+main ()
+{
+
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_cxx_try_compile "$LINENO"; then :
+ ac_uchar_c8rtomb_mbrtoc8_cxx20=yes
+else
+ ac_uchar_c8rtomb_mbrtoc8_cxx20=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ else
+ ac_uchar_c8rtomb_mbrtoc8_cxx20=no
+ fi
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_uchar_c8rtomb_mbrtoc8_cxx20" >&5
+$as_echo "$ac_uchar_c8rtomb_mbrtoc8_cxx20" >&6; }
+ if test x"$ac_uchar_c8rtomb_mbrtoc8_cxx20" = x"yes"; then
+
+$as_echo "#define _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20 1" >>confdefs.h
+
+ fi
+
CXXFLAGS="$ac_save_CXXFLAGS"
ac_ext=c
ac_cpp='$CPP $CPPFLAGS'
@@ -33,6 +33,14 @@
#ifdef _GLIBCXX_NAMESPACE_C
+#if (_GLIBCXX_USE_CHAR8_T \
+ && (_GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T \
+ || (__cplusplus >= 202002 \
+ && _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20)))
+using std::mbrtoc8;
+using std::c8rtomb;
+#endif // _GLIBCXX_USE_CHAR8_T
+
#if _GLIBCXX_USE_C11_UCHAR_CXX11
using std::mbrtoc16;
using std::c16rtomb;
@@ -48,10 +48,41 @@
#include <bits/c++config.h>
#include <cwchar>
-#if _GLIBCXX_USE_C11_UCHAR_CXX11
+#if (_GLIBCXX_USE_C11_UCHAR_CXX11 \
+ || (_GLIBCXX_USE_CHAR8_T \
+ && (_GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T \
+ || (__cplusplus >= 202002 \
+ && _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20))))
#include <uchar.h>
+#endif
+
+
+// Support for mbrtoc8 and c8rtomb is conditioned on support by the C library.
+#if (_GLIBCXX_USE_CHAR8_T \
+ && (_GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T \
+ || (__cplusplus >= 202002 \
+ && _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20)))
+
+#undef mbrtoc8
+#undef c8rtomb
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+ using ::mbrtoc8;
+ using ::c8rtomb;
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // _GLIBCXX_USE_CHAR8_T
+
+
+#if _GLIBCXX_USE_C11_UCHAR_CXX11
+
// Get rid of those macros defined in <uchar.h> in lieu of real functions.
#undef mbrtoc16
#undef c16rtomb
@@ -48,10 +48,42 @@
#include <bits/c++config.h>
#include <cwchar>
-#if _GLIBCXX_USE_C11_UCHAR_CXX11
+#if (_GLIBCXX_USE_C11_UCHAR_CXX11 \
+ || (_GLIBCXX_USE_CHAR8_T \
+ && (_GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T \
+ || (__cplusplus >= 202002 \
+ && _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20))))
#include <uchar.h>
+#endif
+
+
+// Support for mbrtoc8 and c8rtomb is conditioned on support by the C library.
+#if (_GLIBCXX_USE_CHAR8_T \
+ && (_GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T \
+ || (__cplusplus >= 202002 \
+ && _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20)))
+
+// Get rid of those macros defined in <uchar.h> in lieu of real functions.
+#undef mbrtoc8
+#undef c8rtomb
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+ using ::mbrtoc8;
+ using ::c8rtomb;
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // _GLIBCXX_USE_CHAR8_T
+
+
+#if _GLIBCXX_USE_C11_UCHAR_CXX11
+
// Get rid of those macros defined in <uchar.h> in lieu of real functions.
#undef mbrtoc16
#undef c16rtomb
new file mode 100644
@@ -0,0 +1,12 @@
+// { dg-do compile }
+// { dg-options "-std=c++20" }
+
+#include <cuchar>
+
+namespace gnu
+{
+#if _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20
+ using std::mbrtoc8;
+ using std::c8rtomb;
+#endif // _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20
+}
new file mode 100644
@@ -0,0 +1,12 @@
+// { dg-do compile }
+// { dg-options "-fchar8_t" }
+
+#include <cuchar>
+
+namespace gnu
+{
+#if _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T
+ using std::mbrtoc8;
+ using std::c8rtomb;
+#endif // _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T
+}