linux/include/linux/compiler-gcc4.h
David Rientjes 0d7ebbbc6e 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>
2007-05-09 12:30:56 -07:00

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C

/* Never include this file directly. Include <linux/compiler.h> instead. */
/* These definitions are for GCC v4.x. */
#include <linux/compiler-gcc.h>
#ifdef CONFIG_FORCED_INLINING
# undef inline
# undef __inline__
# undef __inline
# define inline inline __attribute__((always_inline))
# define __inline__ __inline__ __attribute__((always_inline))
# define __inline __inline __attribute__((always_inline))
#endif
#define __used __attribute__((__used__))
#define __attribute_used__ __used /* deprecated */
#define __must_check __attribute__((warn_unused_result))
#define __compiler_offsetof(a,b) __builtin_offsetof(a,b)
#define __always_inline inline __attribute__((always_inline))
/*
* A trick to suppress uninitialized variable warning without generating any
* code
*/
#define uninitialized_var(x) x = x