From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52255) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c71N2-0008En-Pp for qemu-devel@nongnu.org; Wed, 16 Nov 2016 09:39:29 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c71My-0002WD-TQ for qemu-devel@nongnu.org; Wed, 16 Nov 2016 09:39:28 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55376) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1c71My-0002Vg-OB for qemu-devel@nongnu.org; Wed, 16 Nov 2016 09:39:24 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5EC095CB for ; Wed, 16 Nov 2016 14:39:23 +0000 (UTC) From: Stefan Hajnoczi Date: Wed, 16 Nov 2016 14:39:21 +0000 Message-Id: <1479307161-24658-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PATCH v2] HACKING: document #include order List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: eblake@redhat.com, Markus Armbruster , Fam Zheng , Stefan Hajnoczi It was not obvious to me why "qemu/osdep.h" must be the first #include. This documents the rationale and the overall #include order. Cc: Fam Zheng Cc: Markus Armbruster Cc: Eric Blake Signed-off-by: Stefan Hajnoczi --- HACKING | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/HACKING b/HACKING index 20a9101..4125c97 100644 --- a/HACKING +++ b/HACKING @@ -1,10 +1,28 @@ 1. Preprocessor +1.1. Variadic macros + For variadic macros, stick with this C99-like syntax: #define DPRINTF(fmt, ...) \ do { printf("IRQ: " fmt, ## __VA_ARGS__); } while (0) +1.2. Include directives + +Order include directives as follows: + +#include "qemu/osdep.h" /* Always first... */ +#include <...> /* then system headers... */ +#include "..." /* and finally QEMU headers. */ + +The "qemu/osdep.h" header contains preprocessor macros that affect the behavior +of core system headers like . It must be the first include so that +core system headers included by external libraries get the preprocessor macros +that QEMU depends on. + +Do not include "qemu/osdep.h" from header files since the .c file will have +already included it. + 2. C types It should be common sense to use the right type, but we have collected -- 2.7.4