[Python-Dev] C99

[Guido van Rossum]

That sounds fine to me, but we need to list specific compiler versions.

On Fri, Aug 5, 2016 at 2:04 PM, Brett Cannon <brett at python.org> wrote:
> Where did we finally land on this discussion? Do we want to update PEP 7 to
> say that starting in 3.6 we may use C99 features common to all supported
> compilers and list what those compilers are (i.e. gcc, clang, and MSVC)?
>
> On Wed, 8 Jun 2016 at 01:28 Victor Stinner <victor.stinner at gmail.com> wrote:
>>
>> I guess that as usual, we should use the "common denominator" of all
>> compilers supported by CPython. For example, if MSVC doesn't support a
>> feature, we should not use it in CPython.
>>
>> In practice, it's easy to check if a feature is supported or not: we
>> have buildbots building Python at each commit. It was very common to
>> get a compilation error only on MSVC when a variable was defined in
>> the middle of a function. We are now using
>> -Werror=declaration-after-statement with GCC because of MSVC!
>>
>> Maybe GCC has an option to ask for the subset of the C99 standard
>> compatible with MSVC? Something like "-std=c99 -pedantic"?
>>
>> Note: I tried -pedantic, GCC emits a lot of warnings on code which
>> looks valid and/or is protected with #ifdef for features specific to
>> GCC like computed goto.
>>
>> Victor
>>
>> 2016-06-07 21:45 GMT+02:00 Guido van Rossum <gvanrossum at gmail.com>:
>> > We should definitely keep supporting MSVC.
>> >
>> > --Guido (mobile)
>> >
>> > On Jun 7, 2016 12:39 PM, "Sturla Molden" <sturla.molden at gmail.com>
>> > wrote:
>> >>
>> >> Victor Stinner <victor.stinner at gmail.com> wrote:
>> >>
>> >> > Is it worth to support a compiler that in 2016 doesn't support the C
>> >> > standard released in 1999, 17 years ago?
>> >>
>> >> MSVC only supports C99 when its needed for C++11 or some MS extension
>> >> to
>> >> C.
>> >>
>> >> Is it worth supporting MSVC? If not, we have Intel C, Clang and Cygwin
>> >> GCC
>> >> are the viable options we have on Windows (and perhaps Embarcadero, but
>> >> I
>> >> haven't used C++ builder for a very long time). Even MinGW does not
>> >> fully
>> >> support C99, because it depends on Microsoft's CRT. If we think MSVC
>> >> and
>> >> MinGW are worth supporting, we cannot just use C99 indiscriminantly.
>> >>
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>> >
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-- 
--Guido van Rossum (python.org/~guido)