gcc 4.3 semantic change of extern inline

[Yuri Dario]

When compiling with -std=c99 or -std=gnu99, the extern inline keywords changes meaning. GCC 4.3 conforms to the ISO C99 specification, where extern inline is very different thing than the GNU extern inline extension.

If the old GNU extern inline behavior is desired, one can use extern inline attribute((gnu_inline)).

Only stdio.h have this problem.

Link: ​http://gcc.gnu.org/gcc-4.3/porting_to.html

[Yuri Dario]

Current patch to stdio.h

--- stdio.h.orig	Sun Jun 10 15:44:44 2007
+++ stdio.h	Sat Aug 28 15:43:52 2010
@@ -526,18 +526,18 @@
 int _flush (int, FILE *);
 int _rmtmp (void);
 
-extern __inline__ int feof (FILE *_s)
+extern inline __attribute__((__gnu_inline__)) int feof (FILE *_s)
 {
   return (_s->_flags & _IOEOF ? 1 : 0);
 }
 
-extern __inline__ int ferror (FILE *_s)
+extern inline __attribute__((__gnu_inline__)) int ferror (FILE *_s)
 {
   return (_s->_flags & _IOERR ? 1 : 0);
 }
 
-extern __inline__ int getchar (void) { return getc (stdin); }
-extern __inline__ int putchar (int _c) { return putc (_c, stdout); }
+extern inline __attribute__((__gnu_inline__)) int getchar (void) { return getc (stdin); }
+extern inline __attribute__((__gnu_inline__)) int putchar (int _c) { return putc (_c, stdout); }
 
 #if !defined (__STRICT_ANSI__) && !defined (_POSIX_SOURCE) || defined(__USE_EMX)
 

[bird]

The patch isn't quite right as we cannot use 'inline' in C headers, it must be 'inline'. The right thing to do here probably static inline func() {}'.

[Yuri Dario]

I built a lot of code using above changes, from basic libs to full applications.

[KO Myung-Hun]

patch for stdio.h

[KO Myung-Hun]

The above patch is the one being shipped with gcc4 in very first place.

See ​http://gcc.gnu.org/onlinedocs/gcc-4.2.4/gcc/Inline.html#Inline

[bird]

(In [3714]) 0.6: Backported r3712 & r3713: stdio.h,features.h: Don't use gcc's 'extern inline' feature with 4.3.0 and later. Fixes #222.