From patchwork Tue Aug 1 13:16:14 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 796235 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3xMH6y4B7Hz9tWN for ; Tue, 1 Aug 2017 23:22:34 +1000 (AEST) Received: from localhost ([::1]:42539 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dcX84-0005qs-El for incoming@patchwork.ozlabs.org; Tue, 01 Aug 2017 09:22:32 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47601) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dcX2T-0001f9-Mm for qemu-devel@nongnu.org; Tue, 01 Aug 2017 09:16:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dcX2S-0005V9-L1 for qemu-devel@nongnu.org; Tue, 01 Aug 2017 09:16:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:62432) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dcX2S-0005Us-Eu for qemu-devel@nongnu.org; Tue, 01 Aug 2017 09:16:44 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 38D52AD80A; Tue, 1 Aug 2017 13:16:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 38D52AD80A Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=stefanha@redhat.com Received: from localhost (ovpn-117-109.ams2.redhat.com [10.36.117.109]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6366167598; Tue, 1 Aug 2017 13:16:39 +0000 (UTC) From: Stefan Hajnoczi To: Date: Tue, 1 Aug 2017 14:16:14 +0100 Message-Id: <20170801131618.27332-6-stefanha@redhat.com> In-Reply-To: <20170801131618.27332-1-stefanha@redhat.com> References: <20170801131618.27332-1-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Tue, 01 Aug 2017 13:16:43 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 5/9] coding_style: add point about 0x in trace-events X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Vladimir Sementsov-Ogievskiy , Stefan Hajnoczi Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: Vladimir Sementsov-Ogievskiy Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake Message-id: 20170731160135.12101-2-vsementsov@virtuozzo.com Signed-off-by: Stefan Hajnoczi --- CODING_STYLE | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/CODING_STYLE b/CODING_STYLE index 2fa0c0b65b..12ba58ee29 100644 --- a/CODING_STYLE +++ b/CODING_STYLE @@ -123,3 +123,38 @@ We use traditional C-style /* */ comments and avoid // comments. Rationale: The // form is valid in C99, so this is purely a matter of consistency of style. The checkpatch script will warn you about this. + +8. trace-events style + +8.1 0x prefix + +In trace-events files, use a '0x' prefix to specify hex numbers, as in: + +some_trace(unsigned x, uint64_t y) "x 0x%x y 0x" PRIx64 + +An exception is made for groups of numbers that are hexadecimal by +convention and separated by the symbols '.', '/', ':', or ' ' (such as +PCI bus id): + +another_trace(int cssid, int ssid, int dev_num) "bus id: %x.%x.%04x" + +However, you can use '0x' for such groups if you want. Anyway, be sure that +it is obvious that numbers are in hex, ex.: + +data_dump(uint8_t c1, uint8_t c2, uint8_t c3) "bytes (in hex): %02x %02x %02x" + +Rationale: hex numbers are hard to read in logs when there is no 0x prefix, +especially when (occasionally) the representation doesn't contain any letters +and especially in one line with other decimal numbers. Number groups are allowed +to not use '0x' because for some things notations like %x.%x.%x are used not +only in Qemu. Also dumping raw data bytes with '0x' is less readable. + +8.2 '#' printf flag + +Do not use printf flag '#', like '%#x'. + +Rationale: there are two ways to add a '0x' prefix to printed number: '0x%...' +and '%#...'. For consistency the only one way should be used. Arguments for +'0x%' are: + - it is more popular + - '%#' omits the 0x for the value 0 which makes output inconsistent