From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41551) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cTxH0-0003tV-Cf for qemu-devel@nongnu.org; Wed, 18 Jan 2017 15:56:03 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cTxGw-0000yG-0J for qemu-devel@nongnu.org; Wed, 18 Jan 2017 15:56:02 -0500 Received: from mail.kernel.org ([198.145.29.136]:56610) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cTxGv-0000xc-Qd for qemu-devel@nongnu.org; Wed, 18 Jan 2017 15:55:57 -0500 Date: Wed, 18 Jan 2017 22:55:52 +0200 From: "Michael S. Tsirkin" Message-ID: <1484772931-16272-4-git-send-email-mst@redhat.com> References: <1484772931-16272-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1484772931-16272-1-git-send-email-mst@redhat.com> Subject: [Qemu-devel] [PATCH v2 3/4] compiler: expression version of QEMU_BUILD_BUG_ON List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: pbonzini@redhat.com, Peter Maydell , Eric Blake , Richard Henderson 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 --- 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. */ -- MST