From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 99983 invoked by alias); 20 Oct 2016 20:30:30 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 80822 invoked by uid 89); 20 Oct 2016 20:30:13 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.2 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=optin, opt-in, central, management X-HELO: mx1.redhat.com Subject: Re: Symbol management in header files To: Joseph Myers References: Cc: GNU C Library From: Florian Weimer Message-ID: <0179e6da-da95-de1d-4323-de24c90fdd0d@redhat.com> Date: Thu, 20 Oct 2016 20:30:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-SW-Source: 2016-10/txt/msg00346.txt.bz2 On 10/18/2016 05:57 PM, Joseph Myers wrote: > On Tue, 18 Oct 2016, Florian Weimer wrote: > >> However, TS 18661-1 added “iszero” to , and this causes some build >> failures. Apparently, the main problem here is that it is a macro, which >> means it is not subject to scoping (which helps C++ in particular to cope with >> definitions of nextup/nextdown/fsub/canonincalize). > > I think some build failures are inevitable with new features in headers; > applications that use _GNU_SOURCE simply need to be updated, _GNU_SOURCE currently is pretty much mandatory for C++, so this isn't really a case of deliberate opt-in. All the build failures I have seen so far were encountered by C++ code. It seem we need to be more careful with adding non-namespaced macros to central header files under _GNU_SOURCE, at least for C++. Thanks, Florian