Commit 921717a2 authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds

[PATCH] Make BUILD_BUG_ON fail at compile time.

Force a compiler error instead of a link error, because they are easier to
track down.  Idea stolen from code by Jan Beulich <jbeulich@novell.com>

If the argument to BUILD_BUG_ON evaluates to non-zero the compiler will do:

	t.c:6: error: size of array `type name' is negative

(surprised that gcc doesn't have an extension for this)
Signed-off-by: default avatar"Andi Kleen" <ak@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 0f3d2bd5
...@@ -307,8 +307,8 @@ struct sysinfo { ...@@ -307,8 +307,8 @@ struct sysinfo {
char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding: libc5 uses this.. */ char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding: libc5 uses this.. */
}; };
extern void BUILD_BUG(void); /* Force a compilation error if condition is false */
#define BUILD_BUG_ON(condition) do { if (condition) BUILD_BUG(); } while(0) #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
#ifdef CONFIG_SYSCTL #ifdef CONFIG_SYSCTL
extern int randomize_va_space; extern int randomize_va_space;
......
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