Re: [PATCH] add attribute none to pthread_setspecific (BZ #27714)

[Florian Weimer via Libc-alpha <libc-alpha@sourceware.org>]

* Martin Sebor via Libc-alpha:

> diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
> index 8e244a77cf..ac56be4d87 100644
> --- a/misc/sys/cdefs.h
> +++ b/misc/sys/cdefs.h
> @@ -592,8 +592,14 @@ _Static_assert (0, "IEEE 128-bits long double requires redirection on this platf
>     array according to access mode, or at least one element when
>     size-index is not provided:
>       access (access-mode, <ref-index> [, <size-index>])  */
> -#define __attr_access(x) __attribute__ ((__access__ x))
> +#  define __attr_access(x) __attribute__ ((__access__ x))
> +#  if __GNUC_PREREQ (11, 0)
> +#    define __attr_access_none(pos) __attribute__ ((__access__ (__none__, pos)))
> +#  endif
>  #else
>  #  define __attr_access(x)
> +#  define __attr_access_none(pos)
> +#endif

I don't think this works because __attr_access_none is not defined for
GCC 10 due to the way the definitions are nested.  I think you should
move the __GNUC_PREREQ (11, 0) check to the top level.

It might be consistent with fewer attribute access extensions to write
__attr_access_none ((__none__, 2)) instead of __attr_access_none (2).

Thanks,
Florian