[PATCH:x11proto] Fix Xfuncproto.h to work when #included in a C89-mode compilation
Alan Coopersmith
alan.coopersmith at oracle.com
Fri Aug 26 21:45:12 PDT 2011
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 not be
used in public/exported API headers we install for other software
to compile against, only in internal sources/headers used in the
X build itself.
Signed-off-by: Alan Coopersmith <alan.coopersmith at oracle.com>
---
Xfuncproto.h.in | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/Xfuncproto.h.in b/Xfuncproto.h.in
index 0d7b8b7..18ce04a 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 not be used in any public/exported API header, 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
--
1.7.3.2
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