/* GL_LINK_WARNING("literal string") arranges to emit the literal string as a linker warning on most glibc systems. We use a linker warning rather than a preprocessor warning, because #warning cannot be used inside macros. */ #ifndef GL_LINK_WARNING /* This works on platforms with GNU ld and ELF object format. Testing __GLIBC__ is sufficient for asserting that GNU ld is in use. Testing __ELF__ guarantees the ELF object format. Testing __GNUC__ is necessary for the compound expression syntax. */ # if defined __GLIBC__ && defined __ELF__ && defined __GNUC__ # define GL_LINK_WARNING(message) \ GL_LINK_WARNING1 (__FILE__, __LINE__, message) # define GL_LINK_WARNING1(file, line, message) \ GL_LINK_WARNING2 (file, line, message) /* macroexpand file and line */ # define GL_LINK_WARNING2(file, line, message) \ GL_LINK_WARNING3 (file ":" #line ": warning: " message) # define GL_LINK_WARNING3(message) \ ({ static const char warning[sizeof (message)] \ __attribute__ ((__unused__, \ __section__ (".gnu.warning"), \ __aligned__ (1))) \ = message "\n"; \ (void)0; \ }) # else # define GL_LINK_WARNING(message) ((void) 0) # endif #endif
