inline

[Alejandro Colomar]

Hi Bruno,

On Tue, Nov 11, 2025 at 07:53:01PM +0100, Bruno Haible wrote:
> Alejandro Colomar wrote:
> > > > -  inline
> > > 
> > > Beware! Only 'static inline' is reasonably portable to C99.
> > > The semantics of 'extern inline' changed in gcc 4.2 / 4.3 / 4.4.
> > 
> > Hmmmm, C99's extern inline is one I'm very interested in.  Would you
> > mind pointing at the changes in 4.x you're referring to?  I'd like to
> > learn about them.
> 
> In gcc < 4.3, 'inline' without 'static' has the semantics described in [1].
> In gcc >= 4.3, 'inline' without 'static' has the semantics described in [2],
> which is consistent with ISO C 99. The old GNU 'inline' semantics can be
> obtained through __attribute__ ((__gnu_inline__)).

Ahhh, yeah, the switch from GNU inline to C99 inline.  I'm aware of
that.  I thought you meant that it changed more than once.

If glibc started using C99 inline, maybe it could be done like this:

	#if defined(__GNUC_GNU_INLINE__)
	#define __inline  extern inline
	#endif

And then use C99 inline everywhere.  That is, use '__inline' in headers,
and 'extern inline' in source files.


Have a lovely night!
Alex

> Gnulib has this summary:
> 
>    GCC 4.3 and above with -std=c99 or -std=gnu99 implements ISO C99
>    inline semantics, unless -fgnu89-inline is used.  It defines a macro
>    __GNUC_STDC_INLINE__ to indicate this situation or a macro
>    __GNUC_GNU_INLINE__ to indicate the opposite situation.
>    GCC 4.2 with -std=c99 or -std=gnu99 implements the GNU C inline
>    semantics but warns, unless -fgnu89-inline is used:
>      warning: C99 inline functions are not supported; using GNU89
>      warning: to disable this warning use -fgnu89-inline or the gnu_inline function attribute
>    It defines a macro __GNUC_GNU_INLINE__ to indicate this situation.
> 
> Btw, there is a typo in misc/sys/cdefs.h; fix attached.
> 
> [1] https://gcc.gnu.org/onlinedocs/gcc-4.2.4/gcc/Inline.html
> [2] https://gcc.gnu.org/onlinedocs/gcc-4.3.6/gcc/Inline.html



-- 
<https://www.alejandro-colomar.es>
Use port 80 (that is, <...:80/>).
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