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bug#63556: 29.0.90; Use of _Generic breaks Emacs build on GCC <4.9
From: |
Eli Zaretskii |
Subject: |
bug#63556: 29.0.90; Use of _Generic breaks Emacs build on GCC <4.9 |
Date: |
Thu, 18 May 2023 14:42:27 +0300 |
> Cc: Spencer Baugh <sbaugh@janestreet.com>, 63556@debbugs.gnu.org
> Date: Thu, 18 May 2023 19:11:07 +0800
> From: Po Lu via "Bug reports for GNU Emacs,
> the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
>
> Paul Eggert <eggert@cs.ucla.edu> writes:
>
> > Thanks for reporting the problem. Since _Generic is used here merely
> > as a micro-optimization on 32-bit platforms, it's not worth whatever
> > porting hassle you've run into, so I installed the attached patch so
> > that modiff no longer uses _Generic.
>
> Would anyone mind if I made configure check for that?
Depends on how complex is that, and what problem does it solve.
> Btw, couldn't the macro be defined to something along the lines of this
> when the compiler only supports C99?
>
> #define foo(expression) \
> (sizeof (expression) == sizeof (signed char) \
> ? code_for_signed_char \
> : (sizeof (expression) == sizeof (short int) \
> ? code_for_short_int \
> : (sizeof (expression) == sizeof (int) \
> ? code_for_int \
> ... and so on
AFAIR, sizeof is a compile-time expression, the preprocessor cannot
evaluate it.
- bug#63556: 29.0.90; Use of _Generic breaks Emacs build on GCC <4.9, Spencer Baugh, 2023/05/17
- bug#63556: 29.0.90; Use of _Generic breaks Emacs build on GCC <4.9, Eli Zaretskii, 2023/05/17
- bug#63556: 29.0.90; Use of _Generic breaks Emacs build on GCC <4.9, Paul Eggert, 2023/05/17
- bug#63556: 29.0.90; Use of _Generic breaks Emacs build on GCC <4.9, Paul Eggert, 2023/05/18
- bug#63556: 29.0.90; Use of _Generic breaks Emacs build on GCC <4.9, Po Lu, 2023/05/18
- bug#63556: 29.0.90; Use of _Generic breaks Emacs build on GCC <4.9, Paul Eggert, 2023/05/18
- bug#63556: 29.0.90; Use of _Generic breaks Emacs build on GCC <4.9, Po Lu, 2023/05/18
bug#63556: 29.0.90; Use of _Generic breaks Emacs build on GCC <4.9, Paul Eggert, 2023/05/18