The configure test checking for alignas and alignof... reports 'yes, <stdalign.h> macros' with gcc, but 'no' with clang 17 and CC="clang -std=gnu2x". In my opinion, this is a clang bug. This patch documents it.
2024-02-12 Bruno Haible <br...@clisp.org> stdalign: Document a clang 17 bug. * doc/posix-headers/stdalign.texi: Mention a clang 17 bug. diff --git a/doc/posix-headers/stdalign.texi b/doc/posix-headers/stdalign.texi index 7f75a15540..4f9c2dd186 100644 --- a/doc/posix-headers/stdalign.texi +++ b/doc/posix-headers/stdalign.texi @@ -45,6 +45,10 @@ @code{alignasof} module, as such code should use @code{alignas} and @code{alignof} without checking these two macros. (Gnulib's now-deprecated @code{stdalign} module defines these two macros.) +@item +@c https://github.com/llvm/llvm-project/issues/81472 +Clang 17 does not support an @code{alignas} attribute in the +specifier-qualifier position of a member declaration. @end itemize Portability problems not fixed by Gnulib: