extern-inline: make safe for -Wundef usage

[gnulib.git] / m4 / extern-inline.m4

diff --git a/m4/extern-inline.m4 b/m4/extern-inline.m4
index cacf8a0..e4454d8 100644 (file)
--- a/m4/extern-inline.m4
+++ b/m4/extern-inline.m4
@@ -1,39 +1,79 @@
+# extern-inline.m4 serial 2
 dnl 'extern inline' a la ISO C99.
 
-dnl Copyright 2012 Free Software Foundation, Inc.
+dnl Copyright 2012-2013 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_EXTERN_INLINE],
 [
-  AC_REQUIRE([AC_C_INLINE])
   AH_VERBATIM([extern_inline],
-[/* _GL_INLINE is a portable alternative to ISO C99 plain 'inline'.
-   _GL_EXTERN_INLINE is a portable alternative to 'extern inline'.
-   _GL_INLINE_HEADER_BEGIN contains useful stuff to put
-     in an include file, before uses of _GL_INLINE.
-     It suppresses GCC's bogus "no previous prototype for 'FOO'" diagnostic,
-     when FOO is an inline function in the header; see
-     <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54113>.
-   _GL_INLINE_HEADER_END contains useful stuff to put
-     in the same include file, after uses of _GL_INLINE.  */
-#if __GNUC__ ? __GNUC_STDC_INLINE__ : 199901L <= __STDC_VERSION__
+[/* Please see the Gnulib manual for how to use these macros.
+
+   Suppress extern inline with HP-UX cc, as it appears to be broken; see
+   <http://lists.gnu.org/archive/html/bug-texinfo/2013-02/msg00030.html>.
+
+   Suppress extern inline with Sun C in standards-conformance mode, as it
+   mishandles inline functions that call each other.  E.g., for 'inline void f
+   (void) { } inline void g (void) { f (); }', c99 incorrectly complains
+   'reference to static identifier "f" in extern inline function'.
+   This bug was observed with Sun C 5.12 SunOS_i386 2011/11/16.
+
+   Suppress the use of extern inline on problematic Apple configurations, as
+   Libc at least through Libc-825.26 (2013-04-09) mishandles it; see, e.g.,
+   <http://lists.gnu.org/archive/html/bug-gnulib/2012-12/msg00023.html>.
+   Perhaps Apple will fix this some day.  */
+#if (defined __APPLE__ \
+     && ((! defined _DONT_USE_CTYPE_INLINE_ \
+          && (defined __GNUC__ || defined __cplusplus)) \
+         || (defined _FORTIFY_SOURCE && 0 < _FORTIFY_SOURCE \
+             && defined __GNUC__ && ! defined __cplusplus)))
+# define _GL_EXTERN_INLINE_APPLE_BUG
+#endif
+#if ((__GNUC__ \
+      ? defined __GNUC_STDC_INLINE__ && __GNUC_STDC_INLINE__ \
+      : (199901L <= __STDC_VERSION__ \
+         && !defined __HP_cc \
+         && !(defined __SUNPRO_C && __STDC__))) \
+     && !defined _GL_EXTERN_INLINE_APPLE_BUG)
 # define _GL_INLINE inline
 # define _GL_EXTERN_INLINE extern inline
-# if (__GNUC__ == 4 && 6 <= __GNUC_MINOR__) || 4 < __GNUC__
-#  define _GL_INLINE_HEADER_BEGIN \
-     _Pragma ("GCC diagnostic push") \
-     _Pragma ("GCC diagnostic ignored \"-Wmissing-prototypes\"")
-#  define _GL_INLINE_HEADER_END \
-     _Pragma ("GCC diagnostic pop")
+# define _GL_EXTERN_INLINE_IN_USE
+#elif (2 < __GNUC__ + (7 <= __GNUC_MINOR__) && !defined __STRICT_ANSI__ \
+       && !defined _GL_EXTERN_INLINE_APPLE_BUG)
+# if defined __GNUC_GNU_INLINE__ && __GNUC_GNU_INLINE__
+   /* __gnu_inline__ suppresses a GCC 4.2 diagnostic.  */
+#  define _GL_INLINE extern inline __attribute__ ((__gnu_inline__))
+# else
+#  define _GL_INLINE extern inline
 # endif
+# define _GL_EXTERN_INLINE extern
+# define _GL_EXTERN_INLINE_IN_USE
 #else
-# define _GL_INLINE static inline
-# define _GL_EXTERN_INLINE static inline
+# define _GL_INLINE static _GL_UNUSED
+# define _GL_EXTERN_INLINE static _GL_UNUSED
 #endif
 
-#ifndef _GL_INLINE_HEADER_BEGIN
+#if 4 < __GNUC__ + (6 <= __GNUC_MINOR__)
+# if defined __GNUC_STDC_INLINE__ && __GNUC_STDC_INLINE__
+#  define _GL_INLINE_HEADER_CONST_PRAGMA
+# else
+#  define _GL_INLINE_HEADER_CONST_PRAGMA \
+     _Pragma ("GCC diagnostic ignored \"-Wsuggest-attribute=const\"")
+# endif
+  /* Suppress GCC's bogus "no previous prototype for 'FOO'"
+     and "no previous declaration for 'FOO'"  diagnostics,
+     when FOO is an inline function in the header; see
+     <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54113>.  */
+# define _GL_INLINE_HEADER_BEGIN \
+    _Pragma ("GCC diagnostic push") \
+    _Pragma ("GCC diagnostic ignored \"-Wmissing-prototypes\"") \
+    _Pragma ("GCC diagnostic ignored \"-Wmissing-declarations\"") \
+    _GL_INLINE_HEADER_CONST_PRAGMA
+# define _GL_INLINE_HEADER_END \
+    _Pragma ("GCC diagnostic pop")
+#else
 # define _GL_INLINE_HEADER_BEGIN
 # define _GL_INLINE_HEADER_END
 #endif])