Re: [PATCH 0/2] kbuild: Switch from '-fms-extensions' to '-fms-anonymous-structs' when available

Nathan Chancellor
2026-03-06T23:17:15Z

On Thu, Mar 05, 2026 at 03:43:29PM -0800, H. Peter Anvin wrote:
> Question: does clang allow this with __extension__, or only if the option is
> on the command line? It would be desirable in the long run if both clang and

It looks like only on the command line:

https://godbolt.org/z/zrE766obe

> gcc would allow this with __extension__, as that would be required to use it
> in uapi headers (at least without some doable-but-nontrivial preprocessing,
> which might be worthwhile to do anyway...)

I agree that would be desirable but wouldn't that change how
__extension__ works? As far as I can tell from reading GCC's
documentation [1], __extension__ just supresses warnings from -pedantic
and such, it does not actually enable a used extension if it conflicts
with whatever -std= value is passed?

[1]: https://gcc.gnu.org/onlinedocs/gcc/Alternate-Keywords.html

Cheers,
Nathan