"Michael S. Tsirkin" <m...@redhat.com> writes: > QEMU_BUILD_BUG_ON uses a typedef in order to be safe > to use outside functions, but sometimes it's useful > to have a version that can be used within an expression. > Following what Linux does, introduce QEMU_BUILD_BUG_ON_ZERO > that return zero after checking condition at build time.
Following Linux's example makes sense, but I can't help but wonder whether we need both QEMU_BUILD_BUG_ON_ZERO() and QEMU_BUILD_BUG_ON(). > Signed-off-by: Michael S. Tsirkin <m...@redhat.com> > --- > include/qemu/compiler.h | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h > index 2882470..f4cf13b 100644 > --- a/include/qemu/compiler.h > +++ b/include/qemu/compiler.h > @@ -89,6 +89,8 @@ > typedef char glue(qemu_build_bug_on__,__LINE__)[(x) ? -1 : 1] \ > __attribute__((unused)) > > +#define QEMU_BUILD_BUG_ON_ZERO(x) (sizeof(int[(x) ? -1 : 1]) - sizeof(int)) > + > #if defined __GNUC__ > # if !QEMU_GNUC_PREREQ(4, 4) > /* gcc versions before 4.4.x don't support gnu_printf, so use printf. */ More so since your QEMU_BUILD_BUG_ON_ZERO seems easier to understand: no token pasting. Anyway, Reviewed-by: Markus Armbruster <arm...@redhat.com>
