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 [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id DFD273858C83 for ; Mon, 27 Mar 2023 15:43:18 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org DFD273858C83 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1679931798; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=rASv4vuWsTBNHTXhkUSh84FIclpEVf+mi42FECbjQr0=; b=UgFCkYrA0efqUMdSlsLFoH2wqJ+y8fthqtVB3JmegJo6adMquabhnYVOpCDnGv0+k2FBke X94bAqh/EyiOwWjMdxBd0LaJaOfjAyo7fncvHnY/+slQsdFId04JunHEnSStglNT2MTc/i kPB5wzyYNZdP29Vz92L6MPaumvn1rQg= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-124-yVKDtwNmPLmNd5Cifk9wIQ-1; Mon, 27 Mar 2023 11:43:14 -0400 X-MC-Unique: yVKDtwNmPLmNd5Cifk9wIQ-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id A6B1B884EC7; Mon, 27 Mar 2023 15:43:13 +0000 (UTC) Received: from tucnak.zalov.cz (unknown [10.39.192.16]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 535DA492C3E; Mon, 27 Mar 2023 15:43:13 +0000 (UTC) Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.17.1/8.17.1) with ESMTPS id 32RFh9YF3451637 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Mon, 27 Mar 2023 17:43:10 +0200 Received: (from jakub@localhost) by tucnak.zalov.cz (8.17.1/8.17.1/Submit) id 32RFh8AZ3451636; Mon, 27 Mar 2023 17:43:08 +0200 Date: Mon, 27 Mar 2023 17:43:08 +0200 From: Jakub Jelinek To: Qing Zhao Cc: Joseph Myers , "sandra@codesourcery.com" , Siddhesh Poyarekar , Kees Cook , Richard Biener , gcc Patches Subject: Re: [V5][PATCH 2/2] Update documentation to clarify a GCC extension Message-ID: Reply-To: Jakub Jelinek References: <20230316214715.604671-3-qing.zhao@oracle.com> <4a128885-687d-9c22-778-811816b2e535@codesourcery.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 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=-3.3 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Mon, Mar 27, 2023 at 01:38:34PM +0000, Qing Zhao wrote: > > > > On Mar 23, 2023, at 4:14 PM, Joseph Myers wrote: > > > > On Thu, 23 Mar 2023, Qing Zhao via Gcc-patches wrote: > > > >> +Wgnu-variable-sized-type-not-at-end > >> +C C++ Var(warn_variable_sized_type_not_at_end) Warning > >> +Warn about structures or unions with C99 flexible array members are not > >> +at the end of a structure. > > > > I think there's at least one word missing here, e.g. "that" before "are". > > Will fix it. > > > >> +Please use warning option @option{-Wgnu-variable-sized-type-not-at-end} to > >> +identify all such cases in the source code and modify them. This extension > >> +will be deprecated from gcc in the next release. > > > > We don't generally say "in the next release" in the manual (or "deprecated > > from gcc"). Maybe it *is* deprecated, maybe it will be *removed*, or will > > *start to warn by default*, in some specified version number (giving a > > version number seems better than "next release"), but "will be deprecated" > > is odd. > How about the following: > > +Please use warning option @option{-Wgnu-variable-sized-type-not-at-end} to This is certainly misnamed. GNU variable sized type not at the end of a struct is something like void bar (void *); void foo (int n) { struct S { int a; int b[n]; int c; } s; s.a = 1; __builtin_memset (s.b, 0, sizeof (s.b)); s.c = 3; bar (&s); } Certainly not flexible array members in the middle of structure. > +identify all such cases in the source code and modify them. This warning will be > + on by default starting from GCC14. Jakub