From owner-sc22wg14+sc22wg14-domo2=www.open-std.org@open-std.org Thu Jul 28 18:14:40 2016 Return-Path: X-Original-To: sc22wg14-domo2 Delivered-To: sc22wg14-domo2@www.open-std.org Received: by www.open-std.org (Postfix, from userid 521) id 11D8635889E; Thu, 28 Jul 2016 18:14:40 +0200 (CEST) Delivered-To: sc22wg14@open-std.org X-Greylist: delayed 1348 seconds by postgrey-1.34 at www5.open-std.org; Thu, 28 Jul 2016 18:14:39 CEST Received: from relay1.mentorg.com (relay1.mentorg.com [192.94.38.131]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by www.open-std.org (Postfix) with ESMTP id B0A38358679 for ; Thu, 28 Jul 2016 18:14:38 +0200 (CEST) Received: from nat-ies.mentorg.com ([192.94.31.2] helo=SVR-IES-FEM-01.mgc.mentorg.com) by relay1.mentorg.com with esmtp id 1bSnbQ-0002cp-Nx from joseph_myers@mentor.com for sc22wg14@open-std.org; Thu, 28 Jul 2016 08:52:04 -0700 Received: from digraph.polyomino.org.uk (137.202.0.76) by SVR-IES-FEM-01.mgc.mentorg.com (137.202.0.104) with Microsoft SMTP Server id 14.3.224.2; Thu, 28 Jul 2016 16:52:02 +0100 Received: from jsm28 (helo=localhost) by digraph.polyomino.org.uk with local-esmtp (Exim 4.86_2) (envelope-from ) id 1bSnbN-0000lV-G9 for sc22wg14@open-std.org; Thu, 28 Jul 2016 15:52:01 +0000 Date: Thu, 28 Jul 2016 15:52:01 +0000 From: Joseph Myers X-X-Sender: jsm28@digraph.polyomino.org.uk To: "sc22wg14@open-std.org" Subject: Re: (SC22WG14.14298) flexible array member in an anonymous struct In-Reply-To: <20160728154347.8BE3D3587A8@www.open-std.org> Message-ID: References: <20160728154347.8BE3D3587A8@www.open-std.org> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Sender: owner-sc22wg14@open-std.org Precedence: bulk On Thu, 28 Jul 2016, Martin Sebor wrote: > I think another reasonable interpretation is that since according > to 6.7.2.1, p3, "members of an anonymous structure or union are > considered to be members of the containing structure or union," > the code above is valid. Note that the "considered to be members" wording also caused the confusion described in DR#499. My understanding has always been that the layout is exactly as if the contained anonymous structure or union had a name (so it acts like a structure is declared as such even if contained in a union, or like a union if declared as such even if contained in a structure), with all the usual constraints applying to the contained structure or union, and the only difference being a shorthand notation for naming members of the contained structure or union. Note also that this feature is not a committee invention (although the interaction with flexible array members may be); it may have originated in MS or Plan 9 compilers. -- Joseph S. Myers joseph@codesourcery.com