diff options
| author | Alan Coopersmith <alan.coopersmith@oracle.com> | 2011-08-26 13:55:29 -0700 |
|---|---|---|
| committer | Alan Coopersmith <alan.coopersmith@oracle.com> | 2011-08-30 16:29:29 -0700 |
| commit | c270f8bed465daff386967c5586eb3c8490b86e0 (patch) | |
| tree | 4dcc4da8078f3c2a46791405b5037fd934059e1c /Xfuncproto.h.in | |
| parent | 06ebd5b88bee8c54222bde3178dc773776036802 (diff) | |
Fix Xfuncproto.h to work when #included in a C89-mode compilation
Variable argument macros are not supported in C89, only C99 or a
compiler-specific extension like gcc's. Even just defining the
macro causes builds with C89 compilers to fail, as they can't
figure out how to handle #define _X_NONNULL(...), so only define
the fallback for C99 compilers.
Since this means C89 compilers will see _X_NONNULL unexpanded in
sources, add a comment to remind users that this should only be
used with #ifdef _X_NONNULL guards in public/exported API headers
we install for other software to compile against, so that we don't
break their builds.
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Reviewed-by: Julien Cristau <jcristau@debian.org>
Diffstat (limited to 'Xfuncproto.h.in')
| -rw-r--r-- | Xfuncproto.h.in | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/Xfuncproto.h.in b/Xfuncproto.h.in index 0d7b8b7..dc913fa 100644 --- a/Xfuncproto.h.in +++ b/Xfuncproto.h.in @@ -128,10 +128,12 @@ in this Software without prior written authorization from The Open Group. # define _X_ATTRIBUTE_PRINTF(x,y) #endif -/* requires xproto >= 7.0.22 */ +/* requires xproto >= 7.0.22 - since this uses either gcc or C99 variable + argument macros, must be only used inside #ifdef _X_NONNULL guards, as + many legacy X clients are compiled in C89 mode still. */ #if defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 303) #define _X_NONNULL(args...) __attribute__((nonnull(args))) -#else +#elif defined(__STDC_VERSION__) && (__STDC_VERSION__ - 0 >= 199901L) /* C99 */ #define _X_NONNULL(...) /* */ #endif |