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Re: [patch] Fix for BZ #15366 (ignore __STDC_LIMIT_MACROS, __STDC_CONSTANT_MACROS)
- From: Richard Smith <richardsmith at google dot com>
- To: Paul Pluzhnikov <ppluzhnikov at google dot com>
- Cc: Rich Felker <dalias at aerifal dot cx>, Florian Weimer <fweimer at redhat dot com>, libc-alpha at sourceware dot org
- Date: Mon, 22 Apr 2013 13:25:01 -0700
- Subject: Re: [patch] Fix for BZ #15366 (ignore __STDC_LIMIT_MACROS, __STDC_CONSTANT_MACROS)
- References: <ye6qhaj75q8n dot fsf at elbrus2 dot mtv dot corp dot google dot com> <516CFD67 dot 2010009 at redhat dot com> <CALoOobMkrkFtqeNWF7dhEfnYV8=hNUvwKq+X4md=8mDfawd5vA at mail dot gmail dot com> <516D71F0 dot 5090500 at redhat dot com> <20130416160428 dot GY20323 at brightrain dot aerifal dot cx> <CALoOobNcA1T=71fyhfeJi53eqY8Vt83tjOFgGp7=rpopF2nGEg at mail dot gmail dot com> <CAGL0aWeqHv7QxphsX0THtkZ6zse=3WynenJ85DGxBhNkMFh0Xg at mail dot gmail dot com>
I've done a little more digging. The text was added to C here (I can
find no indication that they liaised with the C++ committee before
adding it):
http://www.open-std.org/jtc1/sc22/wg14/www/docs/n851.htm
and it was removed as an *editorial* change here:
http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1426.pdf
"Removed the C++ feature test macros from 7.8.1, 7.19.2, 7.19.3, and
7.19.4 since C++ has never
used them"
On Mon, Apr 22, 2013 at 10:25 AM, Richard Smith <richardsmith@google.com> wrote:
> On Mon, Apr 22, 2013 at 8:37 AM, Paul Pluzhnikov <ppluzhnikov@google.com> wrote:
>>
>> On Tue, Apr 16, 2013 at 9:04 AM, Rich Felker <dalias@aerifal.cx> wrote:
>>
>> > I don't think real-world code was ever a consideration. It was some
>> > stupid thing about the C++ committee not wanting them (being allergic
>> > to macros?) and the preprocessor conditionals were to satisfy them.
>> > Can anyone confirm if this is correct?
>>
>> Ping?
>
> I'm not sure on the history here, but I don't think the C++ committee
> ever wanted the __STDC_WHATEVER_MACROS #defines to do anything -- I
> think that was just the C committee trying to predict what the C++
> committee would want and guessing wrong (the __STDC_* macro names are
> a C convention). Alternatively, it's possible that the C++ committee
> changed their minds in the time between the publishing of C99 and of
> C++11. If that distinction really matters, I could ask around and see
> if anyone on the C++ committee can remember that far back...
>
> In any case, the first version of the C++ standard which includes a
> <stdint.h> explicitly says "ignore the C standard, those macros do
> nothing in C++, we want everything in <stdint.h>", and C11 took out
> the description of these macros (I believe at the request of the C++
> committee). I think that makes it clear that including any mention of
> these macros in the C standard was just a mistake (now rectified), and
> that these macros should never be checked in any revision of C++ (or
> C).
> --
> Richard