Messages in this thread Patch in this message | | | Subject | [PATCH 1/4] compiler.h: introduce unused_expression() macro | From | Konstantin Khlebnikov <> | Date | Wed, 25 Apr 2012 15:26:23 +0400 |
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Sometimes we want to check some expressions correctness in compile-time without generating extra code. "(void)(e)" does not work if expression has side-effects. This patch introduces macro unused_expression() which helps in this situation.
Cast to "long" required because sizeof does not work for bit-fields.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> --- include/linux/compiler.h | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 923d093..46fbda3 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -310,4 +310,6 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect); */ #define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x)) +#define unused_expression(e) ((void)(sizeof((__force long)(e)))) + #endif /* __LINUX_COMPILER_H */
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