Re: [PATCH] stdlib: DIAG_IGNORE_NEEDS_COMMENT setenv.c

[Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>]

On 30/08/22 04:15, Florian Weimer wrote:
> * Adhemerval Zanella via Libc-alpha:
> 
>> Checked on x86_64-linux-gnu.
>> ---
>>  stdlib/setenv.c | 8 +++++---
>>  1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/stdlib/setenv.c b/stdlib/setenv.c
>> index 2176cbac31..2add8bfb41 100644
>> --- a/stdlib/setenv.c
>> +++ b/stdlib/setenv.c
>> @@ -19,12 +19,14 @@
>>  # include <config.h>
>>  #endif
>>  
>> +#if _LIBC
>> +# include <libc-diag.h>
>>  /* Pacify GCC; see the commentary about VALLEN below.  This is needed
>>     at least through GCC 4.9.2.  Pacify GCC for the entire file, as
>>     there seems to be no way to pacify GCC selectively, only for the
>> -   place where it's needed.  Do not use DIAG_IGNORE_NEEDS_COMMENT
>> -   here, as it's not defined yet.  */
>> -#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
>> +   place where it's needed.  */
>> +DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wmaybe-uninitialized");
>> +#endif
> 
> The comment was added in:
> 
> commit 03c1e456b079929a8290aeb4aadb05c0df73bfd2
> Author: Paul Eggert <eggert@cs.ucla.edu>
> Date:   Sun Apr 19 01:06:33 2015 -0700
> 
>     Better fix for setenv (..., NULL, ...)
>     
>     * stdlib/setenv.c (__add_to_environ):
>     Dump core quickly if setenv (..., NULL, ...) is called.
>     This time, do it the right way, and pacify GCC with a pragma.
> 
> Paul, what did you mean when you wrote “not defined yet”?  Is it a
> gnulib thing?

Paul, is anything to prevent us to use DIAG_IGNORE_NEEDS_COMMENT here?
For glibc it is the best way to possible handle different compiler that
might not need to define it.