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authorDavid Rientjes <rientjes@google.com>2007-05-09 02:35:27 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-09 12:30:56 -0700
commit0d7ebbbc6eaa5539f78ab20ed6ff1725a4e332ef (patch)
treeddef8183ac6440e96678fd4d1159ee86619e2a97 /include/linux/compiler-gcc3.h
parentf7e4217b007d1f73e7e3cf10ba4fea4a608c603f (diff)
downloadlwn-0d7ebbbc6eaa5539f78ab20ed6ff1725a4e332ef.tar.gz
lwn-0d7ebbbc6eaa5539f78ab20ed6ff1725a4e332ef.zip
compiler: introduce __used and __maybe_unused
__used is defined to be __attribute__((unused)) for all pre-3.3 gcc compilers to suppress warnings for unused functions because perhaps they are referenced only in inline assembly. It is defined to be __attribute__((used)) for gcc 3.3 and later so that the code is still emitted for such functions. __maybe_unused is defined to be __attribute__((unused)) for both function and variable use if it could possibly be unreferenced due to the evaluation of preprocessor macros. Function prototypes shall be marked with __maybe_unused if the actual definition of the function is dependant on preprocessor macros. No update to compiler-intel.h is necessary because ICC supports both __attribute__((used)) and __attribute__((unused)) as specified by the gcc manual. __attribute_used__ is deprecated and will be removed once all current code is converted to using __used. Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Adrian Bunk <bunk@stusta.de> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/compiler-gcc3.h')
-rw-r--r--include/linux/compiler-gcc3.h6
1 files changed, 4 insertions, 2 deletions
diff --git a/include/linux/compiler-gcc3.h b/include/linux/compiler-gcc3.h
index ecd621fd27d2..a9e2863c2dbf 100644
--- a/include/linux/compiler-gcc3.h
+++ b/include/linux/compiler-gcc3.h
@@ -4,9 +4,11 @@
#include <linux/compiler-gcc.h>
#if __GNUC_MINOR__ >= 3
-# define __attribute_used__ __attribute__((__used__))
+# define __used __attribute__((__used__))
+# define __attribute_used__ __used /* deprecated */
#else
-# define __attribute_used__ __attribute__((__unused__))
+# define __used __attribute__((__unused__))
+# define __attribute_used__ __used /* deprecated */
#endif
#if __GNUC_MINOR__ >= 4