Commit 921717a2 authored Sep 13, 2005 by Andi Kleen Committed by Linus Torvalds Sep 13, 2005

[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: "Andi Kleen" <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent 0f3d2bd5

include/linux/kernel.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -307,8 +307,8 @@ struct sysinfo {
		char _f[20-2sizeof(long)-sizeof(int)]; / Padding: libc5 uses this.. */
		};

		extern void BUILD_BUG(void);
		#define BUILD_BUG_ON(condition) do { if (condition) BUILD_BUG(); } while(0)
		/* Force a compilation error if condition is false */
		#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))

		#ifdef CONFIG_SYSCTL
		extern int randomize_va_space;