Is stdatomic.h optional or required?

[Rosuav (Chris Angelico)]

@ngoldbaum

I suspect the person in the other thread is using a somewhat nonstandard compiler setup that isn’t covered by CPython’s CI, and is somehow not hitting the LLVM or GCC-specific fallbacks in the pyatomic header. Some more info about what compiler toolchain they’re using would be helpful, I think, unless I missed that detail somewhere.

The best info we have so far is:

@zuhu2195

Regarding your first question, my platform is NonStop(Non-Standard but similar to IBM AIX). Our compilers support C11 standards.

but “C11 standard” doesn’t mandate stdatomic, so it’s entirely possible that it’s not GCC and doesn’t have stdatomic.

I’ll ask, as I’m not sure the OP of that thread saw this thread.

@ngoldbaum

CPython has required atomic support to build for a while now. It doesn’t require stdatomic support, and as explained elsewhere will fall back to platform-specific code, but will error out if it can’t find a platform-specific definition at build time.

That sounds like the wording of the configure message should be adjusted, then; the build requires stdatomic now, as opposed to potentially requiring it in the future.