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=-5.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,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 CD5C3C433E0 for ; Wed, 13 Jan 2021 23:09:54 +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 5F2FC2310A for ; Wed, 13 Jan 2021 23:09:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5F2FC2310A 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]:50594 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kzpGz-0007oD-Fc for qemu-devel@archiver.kernel.org; Wed, 13 Jan 2021 18:09:53 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:54514) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kzpGD-0007Cd-4S for qemu-devel@nongnu.org; Wed, 13 Jan 2021 18:09:05 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:21046) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kzpGB-000546-Cl for qemu-devel@nongnu.org; Wed, 13 Jan 2021 18:09:04 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1610579341; 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=adga8bnwqKrCM9flGm5e7dpJgFae/EYRaa4VoBSswVI=; b=CkOXKvYbhJHpX0fBPJQ8KaI8DLjDyeKv3642cuL0T8SwubnAIIlwQ+w0MPv8lmEa9/yewQ z5QY27yMG1y0l1NF2Pl0NNGBnrgFu90eYUuUDsTkQZaTiFlEANpeOaGRD1h6tCIeqDkVgp 3XMH4pDbcwvBfuJiZFEPLbj8Tj9HeHE= 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-57-ZPF4YAhaNTWdoaxoGyGcvg-1; Wed, 13 Jan 2021 18:09:00 -0500 X-MC-Unique: ZPF4YAhaNTWdoaxoGyGcvg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id F3F57180A086; Wed, 13 Jan 2021 23:08:58 +0000 (UTC) Received: from [10.10.120.151] (ovpn-120-151.rdu2.redhat.com [10.10.120.151]) by smtp.corp.redhat.com (Postfix) with ESMTP id DC16D60BD9; Wed, 13 Jan 2021 23:08:53 +0000 (UTC) Subject: Re: [PATCH 1/2] trace: document how to specify multiple --trace patterns To: Eric Blake , Stefan Hajnoczi , BALATON Zoltan References: <20210112165859.225534-1-stefanha@redhat.com> <20210112165859.225534-2-stefanha@redhat.com> <542c6083-37ef-8a7c-7b24-f1e4f8dbff3@eik.bme.hu> <20210113094804.GA250553@stefanha-x1.localdomain> From: John Snow Message-ID: <1cd6e449-cdde-adf6-a3ef-b2e95cd04add@redhat.com> Date: Wed, 13 Jan 2021 18:08:53 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jsnow@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=windows-1252; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=jsnow@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.25, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no 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: Peter Maydell , Paolo Bonzini , qemu-devel@nongnu.org, Markus Armbruster Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 1/13/21 5:15 PM, Eric Blake wrote: > On 1/13/21 3:42 PM, John Snow wrote: >> On 1/13/21 4:48 AM, Stefan Hajnoczi wrote: >>>> QEMU options are single dash with double dash accepted for >>>> compatibility but >>>> help and other docs have single dash so these (and below) should be >>>> -trace. >>>> (Also a bit less typing for otherwise already way too long command >>>> lines.) >>> Is this documented somewhere? >>> >>> I was under the impression that '-' is legacy syntax and '--' is the >>> preferred syntax. There are examples of '--' on the QEMU man page. > > Historically, uses of 'getopt_long()' support only double dash, while > 'getopt_long_only()' support both single and double. While qemu does > not use getopt_long_only() (because it rolls its own parser instead), it > certainly tries to behave as if it does. Meanwhile, our other tools > like qemu-img or qemu-storage-daemon use getopt_long(). I'm in favor of > preferring the double-dash in documentation, even when single-dash > works, especially for any option (like --trace) that is used for more > tools than just qemu proper, because it makes for easier copy-paste > between options that work for all tools in the qemu suite rather than > just qemu. > Yes, this makes sense. >>> >>> Let's reach agreement, document it, and then make the documentation >>> consistent. >>> >>> Stefan >> >> My naive impression was that double-dash is the preferred idiom in >> linuxdom in general for any multi-character option. >> >> We might hang on to single-dash for backwards compatibility, but I doubt >> we want to enshrine that as our preferred way. >> >> Is there a reasoning I am unaware of? > > Continuing to document '-machine' instead of '--machine' for qemu is > debatable because we don't support 'qemu-img --machine' or > 'qemu-storage-daemon --machine'; but since 'qemu-img -trace' is an error > while 'qemu-img --trace' works, I'm definitely in favor of preferring > '--trace' everywhere in our docs. > At that point, it's a guessing game as to which binaries support which flags and using which spellings -- maybe some will pick up new flags later and so on. Skip the fuss and just insist on the double dash, I think. --js