Re: [PATCH 1/3] C: Implement C2X N2653 char8_t and UTF-8 string literal changes

[Tom Honermann <tom@honermann.net>]

On 7/27/22 7:20 PM, Joseph Myers wrote:
> On Mon, 25 Jul 2022, Tom Honermann via Gcc-patches wrote:
>
>> diff --git a/gcc/ginclude/stdatomic.h b/gcc/ginclude/stdatomic.h
>> index bfcfdf664c7..75ed7965689 100644
>> --- a/gcc/ginclude/stdatomic.h
>> +++ b/gcc/ginclude/stdatomic.h
>> @@ -49,6 +49,10 @@ typedef _Atomic long atomic_long;
>>   typedef _Atomic unsigned long atomic_ulong;
>>   typedef _Atomic long long atomic_llong;
>>   typedef _Atomic unsigned long long atomic_ullong;
>> +#if (defined(__CHAR8_TYPE__) \
>> +     && (defined(_GNU_SOURCE) || defined(_ISOC2X_SOURCE)))
>> +typedef _Atomic __CHAR8_TYPE__ atomic_char8_t;
>> +#endif
>>   typedef _Atomic __CHAR16_TYPE__ atomic_char16_t;
>>   typedef _Atomic __CHAR32_TYPE__ atomic_char32_t;
>>   typedef _Atomic __WCHAR_TYPE__ atomic_wchar_t;
> GCC headers don't test glibc feature test macros such as _GNU_SOURCE and
> _ISOC2X_SOURCE; they base things only on the standard version (whether
> directly, or indirectly as via __CHAR8_TYPE__) and standard-defined
> feature test macros.

Ok, thank you, that makes sense. I'll follow up with a revised patch 
that removes the additional conditions.

Tom.

>
> (There's one exception in glimits.h - testing __USE_GNU, the macro defined
> internally by glibc's headers - but I don't think that's something we want
> to emulate in new code.)
>