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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 481BEC64EB8 for ; Tue, 9 Oct 2018 15:41:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0CEA120644 for ; Tue, 9 Oct 2018 15:41:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0CEA120644 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726770AbeJIW6s convert rfc822-to-8bit (ORCPT ); Tue, 9 Oct 2018 18:58:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52592 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726393AbeJIW6r (ORCPT ); Tue, 9 Oct 2018 18:58:47 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B5A22308FC51; Tue, 9 Oct 2018 15:41:16 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-120-149.rdu2.redhat.com [10.10.120.149]) by smtp.corp.redhat.com (Postfix) with ESMTP id 56A157E10A; Tue, 9 Oct 2018 15:41:12 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <153616290368.23468.7806230605345568524.stgit@warthog.procyon.org.uk> To: Jan Engelhardt Cc: dhowells@redhat.com, linux-api@vger.kernel.org, linux-kbuild@vger.kernel.org, Coly Li , Kent Overstreet , linux-bcache@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 04/11] UAPI: bcache: Fix use of embedded flexible array MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Date: Tue, 09 Oct 2018 16:41:06 +0100 Message-ID: <17992.1539099666@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Tue, 09 Oct 2018 15:41:17 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jan Engelhardt wrote: > """it [the array size expression] shall be a converted constant expression of > type std::size_t and its value shall be greater than zero.""" > —http://eel.is/c++draft/dcl.array Interesting. You're not actually quoting the full sentence: If the constant-expression is present, it shall be a converted constant expression of type std​::​size_­t and its value shall be greater than zero. This suggests that: __u64 ptr[] is actually valid since: D1 [ constant-expressionopt ] attribute-specifier-seqopt suggests that the part between the brackets is optional. David