bug: introduce BUILD_BUG_ON_INVALID() macro
commitbaf05aa9271bdbc07d3160035a231abc5fbd429a
authorKonstantin Khlebnikov <khlebnikov@openvz.org>
Tue, 29 May 2012 22:06:27 +0000 (29 15:06 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 29 May 2012 23:22:20 +0000 (29 16:22 -0700)
tree201c4f1df332fa2baef4ddfeda6806faf9e2dbc8
parent5febcbe99d4766cc383909c447e002e63d8b4592
bug: introduce BUILD_BUG_ON_INVALID() macro

Sometimes we want to check some expressions correctness at compile time.
"(void)(e);" or "if (e);" can be dangerous if the expression has
side-effects, and gcc sometimes generates a lot of code, even if the
expression has no effect.

This patch introduces macro BUILD_BUG_ON_INVALID() for such checks, it
forces a compilation error if expression is invalid without any extra
code.

[Cast to "long" required because sizeof does not work for bit-fields.]

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/bug.h