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[1/3] system_data_types.7: time_t: Add Versions note

Message ID 20201017213758.9270-1-colomar.6.4.3@gmail.com
State Not applicable
Headers
Series [1/3] system_data_types.7: time_t: Add Versions note |

Commit Message

Alejandro Colomar Oct. 17, 2020, 9:37 p.m. UTC 
  Prior to POSIX.1-2008, POSIX allowed time_t to be a real-floating type.

Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
---

Hi Michael,

I found this thing when writing about clock_t.

BTW, I'm not sure about the .PP before the paragraph
(it feels like "Versions" is too far away from it),
but it's unrelated to the previous Versions note, so I kept it.

Regards,

Alex


 man7/system_data_types.7 | 3 +++
 1 file changed, 3 insertions(+)

Comments

Paul Eggert Oct. 18, 2020, 1:05 a.m. UTC | #1 
On 10/17/20 2:37 PM, Alejandro Colomar via Libc-alpha wrote:
>   since POSIX.1-2008.
> +.PP
> +Prior to POSIX.1-2008,
> +the type was either an integer type or a real-floating type.

No actual POSIXish implementation ever made it a real-floating type, though, and 
that point should be made lest some conscientious programmer worry about a 
nonexistent porting issue.
Zack Weinberg Oct. 18, 2020, 2:32 a.m. UTC | #2 
On Sat, Oct 17, 2020 at 9:05 PM Paul Eggert <eggert@cs.ucla.edu> wrote:

> On 10/17/20 2:37 PM, Alejandro Colomar via Libc-alpha wrote:
> >   since POSIX.1-2008.
> > +.PP
> > +Prior to POSIX.1-2008,
> > +the type was either an integer type or a real-floating type.
>
> No actual POSIXish implementation ever made it a real-floating type,
> though, and
> that point should be made lest some conscientious programmer worry about a
> nonexistent porting issue.


It should, at this point, be possible to compile an *exhaustive* list of
all the operating systems where time_t wassn’t an integer and/or didn’t
 count from 1 Jan 1970. Perhaps that list would effectively make the point
that this is not a real portability concern.

zw

>
Michael Kerrisk \(man-pages\) Oct. 18, 2020, 5:46 a.m. UTC | #3 
On 10/18/20 3:05 AM, Paul Eggert wrote:
> On 10/17/20 2:37 PM, Alejandro Colomar via Libc-alpha wrote:
>>   since POSIX.1-2008.
>> +.PP
>> +Prior to POSIX.1-2008,
>> +the type was either an integer type or a real-floating type.
> 
> No actual POSIXish implementation ever made it a real-floating type, though, and 
> that point should be made lest some conscientious programmer worry about a 
> nonexistent porting issue.

Thanks for catching this, Paul!

Alex, I suggest either we drop this patch, or you could reword as
something like: 

"In POSIX.1-2001, the type was specified as being either an integer 
type or a real-floating type. However, existing implementations
used an integer type, and POSIX.1-2008 tightened the specification
to reflect this."

Thanks,

Michael
Alejandro Colomar Oct. 18, 2020, 9:02 a.m. UTC | #4 
On 2020-10-18 07:46, Michael Kerrisk (man-pages) wrote:
> On 10/18/20 3:05 AM, Paul Eggert wrote:
>> On 10/17/20 2:37 PM, Alejandro Colomar via Libc-alpha wrote:
>>>    since POSIX.1-2008.
>>> +.PP
>>> +Prior to POSIX.1-2008,
>>> +the type was either an integer type or a real-floating type.
>>
>> No actual POSIXish implementation ever made it a real-floating type, though, and
>> that point should be made lest some conscientious programmer worry about a
>> nonexistent porting issue.
> 
> Thanks for catching this, Paul!
> 
> Alex, I suggest either we drop this patch, or you could reword as
> something like:
> 
> "In POSIX.1-2001, the type was specified as being either an integer
> type or a real-floating type. However, existing implementations
> used an integer type, and POSIX.1-2008 tightened the specification
> to reflect this."
> 
> Thanks,
> 
> Michael
> 

Thanks, Paul!

Michael, I would opt for the simpler: drop the patch.

Thanks,

Alex
Michael Kerrisk \(man-pages\) Oct. 18, 2020, 1:05 p.m. UTC | #5 
>> Alex, I suggest either we drop this patch, or you could reword as
>> something like:
>>
>> "In POSIX.1-2001, the type was specified as being either an integer
>> type or a real-floating type. However, existing implementations
>> used an integer type, and POSIX.1-2008 tightened the specification
>> to reflect this."
>>
>> Thanks,
>>
>> Michael
>>
> 
> Thanks, Paul!
> 
> Michael, I would opt for the simpler: drop the patch.

Okay.

Thanks,

Michael
diff mbox series

Patch

diff --git a/man7/system_data_types.7 b/man7/system_data_types.7
index 8a894b2e0..dc5f65c0d 100644
--- a/man7/system_data_types.7
+++ b/man7/system_data_types.7
@@ -1236,6 +1236,9 @@  defines
 .I time_t
 since POSIX.1-2008.
+.PP
+Prior to POSIX.1-2008,
+the type was either an integer type or a real-floating type.
 .PP
 Conforming to:
 C99 and later; POSIX.1-2001 and later.
 .PP