From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <joseph_myers@mentor.com>
Received: from esa1.mentor.iphmx.com (esa1.mentor.iphmx.com [68.232.129.153])
	by sourceware.org (Postfix) with ESMTPS id CF9EB38515F8
	for <gcc-patches@gcc.gnu.org>; Wed, 31 Aug 2022 20:09:51 +0000 (GMT)
DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org CF9EB38515F8
Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=codesourcery.com
Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=mentor.com
X-IronPort-AV: E=Sophos;i="5.93,279,1654588800"; 
   d="scan'208";a="85016176"
Received: from orw-gwy-02-in.mentorg.com ([192.94.38.167])
  by esa1.mentor.iphmx.com with ESMTP; 31 Aug 2022 12:09:46 -0800
IronPort-SDR: WWNMaMWPoegOKGqNuvTq3T1pHPazrf5iENv9HY5fIpND4cZitAT6n3km0pGXgQHwNHykmV2YlY
 OkW3eQXi6r+m4z8/RhwAOr3TwtW2NRYU549aVCV/RRSsCpKynljVl0LNn4m5nOPvd5U+e9CYBc
 G/kqAkzW6/RrN3La6FPGREyZ19OQM35xT2E7aCYrsUYAAisss8u6UqqDL5KKg6DW4As/V3bCew
 lnd2wk9fVytiwa4WUCziHrtG88B0JATImYyq8cWU9xEyUCgdIp8hwySmSURHtzeWeLsp91icPh
 a3I=
Date: Wed, 31 Aug 2022 20:09:40 +0000
From: Joseph Myers <joseph@codesourcery.com>
X-X-Sender: jsm28@digraph.polyomino.org.uk
To: Qing Zhao <qing.zhao@oracle.com>
CC: jakub Jelinek <jakub@redhat.com>, richard Biener <rguenther@suse.de>, Kees
 Cook <keescook@chromium.org>, gcc Patches <gcc-patches@gcc.gnu.org>, Nathan
 Sidwell <Nathan@acm.org>, martin Sebor <msebor@gmail.com>
Subject: Re: [[GCC13][Patch][V3] 1/2] Add a new option -fstrict-flex-array[=n]
 and new attribute strict_flex_array
In-Reply-To: <6A951E15-051F-4DBB-97B0-F51DF1E0F7D6@oracle.com>
Message-ID: <alpine.DEB.2.22.394.2208312009090.498823@digraph.polyomino.org.uk>
References: <20220817144042.2931674-1-qing.zhao@oracle.com> <CE639271-B084-48C1-B476-B121E495F370@oracle.com> <alpine.DEB.2.22.394.2208302245520.446383@digraph.polyomino.org.uk> <FE1A2F0B-5306-46A3-A543-6F7632138B15@oracle.com>
 <alpine.DEB.2.22.394.2208311719200.498823@digraph.polyomino.org.uk> <B92A4442-0B40-4C62-A725-FCC8176A00F3@oracle.com> <alpine.DEB.2.22.394.2208311927220.498823@digraph.polyomino.org.uk> <2C0B6A60-A27D-4B96-9559-096712EC32FA@oracle.com>
 <alpine.DEB.2.22.394.2208311950340.498823@digraph.polyomino.org.uk> <6A951E15-051F-4DBB-97B0-F51DF1E0F7D6@oracle.com>
User-Agent: Alpine 2.22 (DEB 394 2020-01-19)
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
X-Originating-IP: [137.202.0.90]
X-ClientProxiedBy: svr-ies-mbx-12.mgc.mentorg.com (139.181.222.12) To
 svr-ies-mbx-10.mgc.mentorg.com (139.181.222.10)
X-Spam-Status: No, score=-3111.4 required=5.0 tests=BAYES_00,HEADER_FROM_DIFFERENT_DOMAINS,KAM_DMARC_STATUS,SPF_HELO_PASS,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org
List-Id: <gcc-patches.gcc.gnu.org>

On Wed, 31 Aug 2022, Qing Zhao wrote:

> >> When -std=gnu89 + -fstrict-flex-array=3 (ONLY C99 flexible array member 
> >> [] is treated as a valid flexible array) present together,
> > 
> > That seems reasonable enough without a warning.  If people want a warning 
> > for flexible array members in older language modes, they can use 
> > -pedantic; I don't think we need to warn for any particular 
> > -fstrict-flex-array modes there.
> 
> So, you mean,
> 
> 1. GCC with -std=gnu89 support all [0], [1], and [] as Flexible array member;
> 2. Therefore. -std=gnu89 + -fstrict-flex-array=3 does not need a warning;
> 
> ?

Yes.

> Then, how about:
> 
> -std=c89:
> 
> 1. GCC with -std=c89 also support all [0], [1], and [] as Flexible array member;
> 2, therefore, -std=c89 + -fstrict-flex-array does not need a warning too.
> 
> ?

Yes.

-- 
Joseph S. Myers
joseph@codesourcery.com