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.
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
Reviewed-by: Eric Blake <ebl...@redhat.com>
Reviewed-by: Markus Armbruster <arm...@redhat.com>
---
include/qemu/compiler.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h
index 1da500e..e0fb18b 100644
--- a/include/qemu/compiler.h
+++ b/include/qemu/compiler.h
@@ -92,6 +92,9 @@
#define QEMU_BUILD_BUG_ON(x) typedef QEMU_BUILD_BUG_ON_STRUCT(x) \
glue(qemu_build_bug_on__, __LINE__) __attribute__((unused))
+#define QEMU_BUILD_BUG_ON_ZERO(x) (sizeof(QEMU_BUILD_BUG_ON_STRUCT(x)) - \
+ sizeof(QEMU_BUILD_BUG_ON_STRUCT(x)))
+
#if defined __GNUC__
# if !QEMU_GNUC_PREREQ(4, 4)
/* gcc versions before 4.4.x don't support gnu_printf, so use printf. */
--
MST
