[FFmpeg-devel] [PATCH] configure: make the check for stdatomic.h stricter

[James Almer]

On 12/28/2016 8:17 PM, Moritz Barsnick wrote:
> On Tue, Dec 27, 2016 at 21:55:42 -0300, James Almer wrote:
>> ICC stdatomic.h implementation seems to be incomplete or broken,
>> missing the ATOMIC_VAR_INIT() macro.
>>
>> Should fix ticket #6049
> 
> Your patch works for me with ICC 14.0.3. I'm the reporter of #6049.
> 
> But see this:
> https://software.intel.com/en-us/articles/c11-support-in-intel-c-compiler
> 
> ICC may have the stdatomic.h header and have some of the features, but
> doesn't actually advertise them (__STDC_VERSION__) before their
> (somewhat) complete implementation in ICC 16. Same situation with gcc
> before 4.7, I guess. Perhaps the check for __STDC_VERSION__ == 201112L
> would "guarantee" the proper availability of atomics (would need to be
> verified on all sorts of compilers), but I guess your check for the
> actually used features is more to the point. Is that check complete
> though?
> 
> Moritz

Such check already exists, but apparently is not thorough enough.
Could you test Michael's "[PATCH] configure: Check build with some header
not just preprocessing for testing --std=c11" to see if it also fixes
this ticket? If so, this patch can be dropped.