From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A6C6C433DF for ; Fri, 15 May 2020 17:25:02 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4017320727 for ; Fri, 15 May 2020 17:25:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Qns2uHK/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4017320727 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:54600 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jZe4z-0000VG-GI for qemu-devel@archiver.kernel.org; Fri, 15 May 2020 13:25:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44650) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jZe4N-0008Iy-V2 for qemu-devel@nongnu.org; Fri, 15 May 2020 13:24:23 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:34373 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jZe4M-0008Ub-HO for qemu-devel@nongnu.org; Fri, 15 May 2020 13:24:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589563461; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6Pl4HzJVB7uTMJhbVdf+AY/dRX81/aJsae0WIaMydEk=; b=Qns2uHK/bgobY/kuL+/hfQoaPXTOi9DqBeRn0wj2KmaTP710J0r7DQDX+F00ZufSFU7ipx aP2zfUyE05Yr5LMB+wx5pL2ji68bnSS5yvkrWlv4tLYe8/AZYVXjxCZ4BTEha6eBSlPqEw XtpNqUxkPHy+1rJXr9/RKNepmzZoL6E= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-125-NwlDlk_GM4CWLzL692xePg-1; Fri, 15 May 2020 13:24:16 -0400 X-MC-Unique: NwlDlk_GM4CWLzL692xePg-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6E90A8015D1; Fri, 15 May 2020 17:24:15 +0000 (UTC) Received: from [10.3.114.84] (ovpn-114-84.phx2.redhat.com [10.3.114.84]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D63306E9E9; Fri, 15 May 2020 17:24:14 +0000 (UTC) Subject: Re: [PATCH v6 04/14] block/amend: separate amend and create options for qemu-img To: Max Reitz , Maxim Levitsky , qemu-devel@nongnu.org References: <20200510134037.18487-1-mlevitsk@redhat.com> <20200510134037.18487-5-mlevitsk@redhat.com> <5b389390-eadb-e1d6-48f8-be99c2dfad99@redhat.com> <52231bba-4ef1-2e96-1e82-9e350a68b106@redhat.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: <3a2238b4-e040-e327-a7dd-831e3f24c808@redhat.com> Date: Fri, 15 May 2020 12:24:14 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=207.211.31.120; envelope-from=eblake@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/14 22:56:02 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= , John Snow , Markus Armbruster , qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 5/15/20 1:22 AM, Max Reitz wrote: >>> >>>> +        QCOW_COMMON_OPTIONS, >>>> +        { /* end of list */ } >> >> ...the intended usage is to use the macro name followed by a comma, so >> including a trailing comma in the macro itself would lead to a syntax >> error. > > But why is that the indended usage? Is there something in our coding > style that forbids macros that don’t allow a separator to be placed > after them? If we have more than one such macro, it is easier to write and indent (especially when using your editor's ability to decipher enough syntax to suggest how to indent): myarray = { COMMON_ELEMENTS, MORE_ELEMENTS, { /* end of list */ } }; than it is: myarray = { COMMON_ELEMENTS MORE_ELEMENTS { /* end of list */ } }; which in turn implies that it is better to NOT stick a trailing comma in the macro itself. Similarly, for macros intended to replace statements, we tend to avoid the trailing ; in the macro itself, because it is easier to read: { code; MACRO(); more code; } than it is: { code; MACRO() more code; } -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org