Re: [RFC PATCH] configure: Fix atomic64 test for --enable-werror on macOS

[Thomas Huth <thuth@redhat.com>]

On 16/07/2020 16.15, Christian Schoenebeck wrote:
> On Donnerstag, 16. Juli 2020 15:11:01 CEST Thomas Huth wrote:
>> When using --enable-werror for the macOS builders in the Cirrus-CI,
>> the atomic64 test is currently failing, and config.log shows a bunch
>> of error messages like this:
>>
>>  config-temp/qemu-conf.c:6:7: error: implicit declaration of function
>>  '__atomic_load_8' is invalid in C99
>> [-Werror,-Wimplicit-function-declaration] y = __atomic_load_8(&x, 0);
>>       ^
>>  config-temp/qemu-conf.c:6:7: error: this function declaration is not a
>>  prototype [-Werror,-Wstrict-prototypes]
> 
> Well, __atomic_*_8() functions do exist on macOS, but it does not look like 
> they are supposed to be 'officially' used.
> 
> You can compile sources with these functions, and yes they are linking fine 
> despite the warning, but IMO not a good idea to use them, as AFAICS they are 
> not defined by any public header file.
> 
>> Suppress the warnings to make it pass.
>>
>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>> ---
>>  Not sure whether this is the best way to fix this issue ... thus marked
>>  as RFC.
> 
> Probably it is better to switch to their official C11 counterpart functions 
> for this test, like e.g. __atomic_load() instead of __atomic_load_8(), etc.
> That's what the actual qemu code base is using actually anyway.

Thanks, that sounds like a good idea! I'll have a try when I've got some
spare minutes...

 Thomas