https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96527
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
CC| |jakub at gcc dot gnu.org
Resolution|--- |INVALID
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The error is correct. __builtin_va_arg_pack_len or __builtin_va_arg_pack can't
work in functions that are not inlined.
And the documentation you refer to is clear about it for both:
"It can be used only in inline functions that are always inlined, never
compiled as a separate function, such as those using __attribute__
((__always_inline__)) or __attribute__ ((__gnu_inline__)) extern inline
functions."
So, either you need to compile with -fgnu-inline, or have the gnu_inline
attribute on it if it is extern inline, or it must be only inline and not
extern inline for the standard C.
extern inline __attribute__ ((__gnu_inline__)) is the mode it was designed for,
if it can be inline, you use something that accesses the ... arguments,
otherwise either you have a guarantee it will never be called out of line, or
there is some external definition which will not use these builtins and will
handle ... normally through va_{list,start,arg,end}.
