Re: git: 28cecfe27964 - main - libc: Restrict ATOMIC_VAR_INIT for C23 conformance

Hey Robert,

>> First, let me add that in case we decide to keep the __BSD_VISIBLE gate, the
>> condition needs to be reconsidered entirely, since __BSD_VISIBLE is 1 in the
>> default environment and makes the __ISO_C_VISIBLE check unreachable in the
>> common case. Ergo, with no explicit feature-test macros, __BSD_VISIBLE is 1
>> unconditionally and the condition __BSD_VISIBLE || __ISO_C_VISIBLE < 2023
>> erroneously exposes ATOMIC_VAR_INIT even when compiled with -std=c23,
>> which the C23 standard explicitly removed.
> 
> That would be correct then.
> We provide this macro as an extension, even if the standard no longer supplies
> it, unless the configuration is set up to disable extensions.
> This is the same policy we follow with all libc symbols and macros, unless
> there is a solid reason not to provide them at all (e.g. due to a type change
> or conflict with a more recent feature).

Oh, alright, now I get the point. I'll keep it in mind. Thanks to both of you for taking
the time to explain. It took me a while to get there, but it's well established in my
head now.

Cheers,
Faraz