220 29115 article Path: news.gmane.org!.POSTED!not-for-mail From: Andrey Semashev Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: pragma once Date: Wed, 26 Oct 2016 19:39:05 +0300 Lines: 29 Approved: news@gmane.org Message-ID: References: <5810C33B.9060503@gmail.com> <2908d573-f002-4b58-b0da-18420a816c16@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed X-Trace: blaine.gmane.org 1477499969 8592 195.159.176.226 (26 Oct 2016 16:39:29 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 26 Oct 2016 16:39:29 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCXY5TXHWYJRBK5YYPAAKGQE7AWGGZA@isocpp.org Wed Oct 26 18:39:24 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-lf0-f69.google.com ([209.85.215.69]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bzREH-000880-Lo for gclcip-std-proposals@m.gmane.org; Wed, 26 Oct 2016 18:39:05 +0200 Original-Received: by mail-lf0-f69.google.com with SMTP id r19sf2554967lfi.8 for ; Wed, 26 Oct 2016 09:39:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:x-original-sender:x-original-authentication-results :reply-to:precedence:mailing-list:list-id:x-spam-checked-in-group :list-post:list-help:list-archive:list-subscribe:list-unsubscribe; bh=3uOKkAtBPzU1Xm9f7wHRH5N+schLYJs1mK7tX5MCDQo=; b=W6lR/eRLVfMtq8WNL6BOd86GYmXT46hyptXxGF/GhfRR/hcEjRo/bNsOeYLKFMuGhn ArMF4IUmY7naZryr0A1TXR7vojZ9fjoReq5wyjjEsRFM30rZ05v7UGiuToes4xr9KZYO GNBjxSayXNBTlua4ixeum8Q5O37B9StyHo1xUwreyGL0zGIH0Jwd9QxZ1Djkav/kMQED MxNfbnf+lLqfzWwNWDM/nbTiGDTizGqsuVRRR40eL///4zh75Gdg6YOM2Hs+Ld+l80/w 7x0kyjR7E1WrxFccMi+0Ve4RAdg6XOr7svlHRBTGclqAOK4dt+HAYUNiA54T/FEJNcLl EsaA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=3uOKkAtBPzU1Xm9f7wHRH5N+schLYJs1mK7tX5MCDQo=; b=JAsrYd2A7Y+hJSy4liRmvNM/OVBpUht7ZenBWH4Qz4xqntGglpyWFGDaIWfqOqs49+ ClCdKE6RkN/vK4LbdUHU6+pdZ4+gm7Ssf7TeXLMzIL4RZB2L5lv4pc9GvHLTYF+gvPXu kF9iaAiMI6PezwYB6XVl/zuVYmAcQCL//xSWUCPMgx8zsFFcxc8YbwE8Gp4xdNn325HF TiT/EX8c9o+0C0hZsZwdEbYZkqEVFXfUGViiQ9HQQhyKsluJaroqTM8/0Z5kxtj5uLrF dRu8eNR6lkrhvm0AYjiEsuu2t8iguowRztzLIV+I4t6gPTC4XpkhDNTlpP5iCAIhT+QG 5qZA== X-Gm-Message-State: ABUngvfWgj9bTJzFRJ0F7NXSLsLVvdm+HPtDCXOt5lon57S5IBlykhXh5l4M0v6Ky4PLVA== X-Received: by 10.25.216.165 with SMTP id r37mr288687lfi.16.1477499948449; Wed, 26 Oct 2016 09:39:08 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.25.72.202 with SMTP id v193ls164304lfa.53.gmail; Wed, 26 Oct 2016 09:39:07 -0700 (PDT) X-Received: by 10.25.31.16 with SMTP id f16mr2267674lff.48.1477499947400; Wed, 26 Oct 2016 09:39:07 -0700 (PDT) Original-Received: from mail-lf0-x231.google.com (mail-lf0-x231.google.com. [2a00:1450:4010:c07::231]) by mx.google.com with ESMTPS id c194si1907710lfe.347.2016.10.26.09.39.07 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 26 Oct 2016 09:39:07 -0700 (PDT) Received-SPF: pass (google.com: domain of andrey.semashev@gmail.com designates 2a00:1450:4010:c07::231 as permitted sender) client-ip=2a00:1450:4010:c07::231; Original-Received: by mail-lf0-x231.google.com with SMTP id x79so9999572lff.0 for ; Wed, 26 Oct 2016 09:39:07 -0700 (PDT) X-Received: by 10.25.195.209 with SMTP id t200mr2689879lff.172.1477499946659; Wed, 26 Oct 2016 09:39:06 -0700 (PDT) Original-Received: from [192.168.1.2] (broadband-90-154-68-136.nationalcablenetworks.ru. [90.154.68.136]) by smtp.googlemail.com with ESMTPSA id j4sm534259lfg.23.2016.10.26.09.39.05 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 26 Oct 2016 09:39:05 -0700 (PDT) In-Reply-To: X-Original-Sender: andrey.semashev@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com; spf=pass (google.com: domain of andrey.semashev@gmail.com designates 2a00:1450:4010:c07::231 as permitted sender) smtp.mailfrom=andrey.semashev@gmail.com; dmarc=pass (p=NONE dis=NONE) header.from=gmail.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:29115 Archived-At: On 10/26/16 19:15, Andrey Semashev wrote: > On 10/26/16 18:28, Hans Guijt wrote: >> >> Can you show an example of #pragma once failing? Otherwise claims like >> "mostly work" are just so much noise in the wind. Your "historical >> problems" seem a collection of far-fetched issues that have no bearing >> on real-life development. And thanks to your comments, I can now add the >> claim that this is a feature commonly requested by the C++ community. > > FWIW, #pragma once was broken in gcc prior to 3.4, it was "confused by > symlinks and hardlinks" [1] before that. The bug is long fixed, but it > indicates that those "historical problems" are not imaginary. You may > also google around and see a few more recent bugs related to #pragma > once, like this[2] for example. > > [1]: https://gcc.gnu.org/gcc-3.4/changes.html > [2]: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58770 BTW, this SO answer and the discussion in the comments might be enlightening: http://stackoverflow.com/questions/1143936/pragma-once-vs-include-guards/34884735#34884735 -- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an email to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/a98fb9f9-cec8-94af-2c2e-f37e094a1702%40gmail.com. .