From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [63.128.21.124]) by sourceware.org (Postfix) with ESMTP id 9970F384BC17 for ; Wed, 17 Mar 2021 17:30:27 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 9970F384BC17 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-404-ZLsUnnXPPO6adfMaZJB_nw-1; Wed, 17 Mar 2021 13:30:24 -0400 X-MC-Unique: ZLsUnnXPPO6adfMaZJB_nw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6AA65107B7C5; Wed, 17 Mar 2021 17:30:23 +0000 (UTC) Received: from tucnak.zalov.cz (ovpn-112-34.ams2.redhat.com [10.36.112.34]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F3B5A10074FC; Wed, 17 Mar 2021 17:30:22 +0000 (UTC) Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.16.1/8.16.1) with ESMTPS id 12HHSKTR145046 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Wed, 17 Mar 2021 18:28:20 +0100 Received: (from jakub@localhost) by tucnak.zalov.cz (8.16.1/8.16.1/Submit) id 12HHSJtX145045; Wed, 17 Mar 2021 18:28:19 +0100 Date: Wed, 17 Mar 2021 18:28:18 +0100 From: Jakub Jelinek To: Tom de Vries Cc: dwz@sourceware.org, mark@klomp.org Subject: Re: [committed] Make main more readable Message-ID: <20210317172818.GI231854@tucnak> Reply-To: Jakub Jelinek References: <20210317131444.GA11885@delia> <20210317131802.GG231854@tucnak> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Status: No, score=-6.1 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: dwz@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Dwz mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 17 Mar 2021 17:30:28 -0000 On Wed, Mar 17, 2021 at 02:37:57PM +0100, Tom de Vries wrote: > On 3/17/21 2:18 PM, Jakub Jelinek wrote: > > On Wed, Mar 17, 2021 at 02:14:45PM +0100, Tom de Vries wrote: > >> @@ -17048,10 +17050,12 @@ main (int argc, char *argv[]) > >> outfile = NULL; > >> hardlink = false; > >> parse_args (argc, argv, &hardlink, &outfile); > >> + nr_files = argc - optind; > >> + files = (const char **)&argv[optind]; > >> > >> - if (optind == argc || optind + 1 == argc) > >> + if (nr_files <= 1) > >> { > >> - const char *file = optind == argc ? "a.out" : argv[optind]; > >> + const char *file = nr_files == 0 ? "a.out" : files[0]; > > > > Isn't that aliasing violation? > > Sorry, I don't see it, can you be specific about which entity is > accessed with an incompatible type? char * and const char * are different types from C aliasing POV I think. Now, as these are arguments of main and argv can be const char ** or char ** interchangeably, what is the dynamic type is a little bit fuzzy, but I'd say mixing accesses to argv array elements, accessing some of them through char * effective type (e.g. in getopt_long) and others through const char * effective type is problematic. Making files char ** and then casting if needed (say (const char *)(files[0])) is fine of course. Jakub