220 14134 article Path: news.gmane.org!not-for-mail From: Olaf van der Spek Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: #pragma once Date: Wed, 22 Oct 2014 20:38:19 +0200 Lines: 32 Approved: news@gmane.org Message-ID: References: <3d0ab5b0-73d9-434a-9ae4-cd47d8275590@isocpp.org> <202c5550-8669-4b45-aa39-9a8d26c37015@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: ger.gmane.org 1414003109 31801 80.91.229.3 (22 Oct 2014 18:38:29 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 22 Oct 2014 18:38:29 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBC5NB45SSABBBHHTT6RAKGQE2EWDFVY@isocpp.org Wed Oct 22 20:38:23 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yh0-f69.google.com ([209.85.213.69]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Xh0ne-0002mh-As for gclcip-std-proposals@m.gmane.org; Wed, 22 Oct 2014 20:38:22 +0200 Original-Received: by mail-yh0-f69.google.com with SMTP id b6sf11660239yha.8 for ; Wed, 22 Oct 2014 11:38:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe:content-type; bh=5Rn/ZSdFw7lUqYXhLUUo062gUgKqfI0qioMmj3PJdkc=; b=NoYpdhIhG70wj9qO9q0E2Zj/IRCpVr21CSopGZAw7g0JUkb3lXx/yo6daPinwAim9g aeGnHzDbD/R/vm4BZ7n08RbgZchxz2cnF9n7mkoQx1qDZWc/1IUgH5F8MBXkK4KioNdX DmG1fx8SLm0rwKhPYQ/llvYZvqeludpMD+aS+Q5ieBmOT3cVheU+/w4s4cdLJ2314rKg q3/u05etkKpZauidmJakQ2YB0CD8Yn4CYOUUKk1iqoBIt1/iwRvw/n+ASRf8Vrj/Jxqd caVQMaJBylRsouSqghijBoCzYWU369IuTFfl2lLF4I81YDDW47ogjrv2uLPMRtW7L6v7 u5+Q== X-Gm-Message-State: ALoCoQkrNL+gK/yQgCEzaa0u8JO/0fUJXqE+pXM1RHQ0u2tPIlMsCO2gy+g8VToSBZow+2HvAFUc X-Received: by 10.236.29.204 with SMTP id i52mr3928yha.14.1414003101217; Wed, 22 Oct 2014 11:38:21 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.140.86.19 with SMTP id o19ls611863qgd.53.gmail; Wed, 22 Oct 2014 11:38:20 -0700 (PDT) X-Received: by 10.224.120.1 with SMTP id b1mr59165815qar.19.1414003100683; Wed, 22 Oct 2014 11:38:20 -0700 (PDT) Original-Received: from mail-qa0-x231.google.com (mail-qa0-x231.google.com. [2607:f8b0:400d:c00::231]) by mx.google.com with ESMTPS id u2si29356970qak.58.2014.10.22.11.38.20 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 22 Oct 2014 11:38:20 -0700 (PDT) Received-SPF: pass (google.com: domain of olafvdspek@gmail.com designates 2607:f8b0:400d:c00::231 as permitted sender) client-ip=2607:f8b0:400d:c00::231; Original-Received: by mail-qa0-f49.google.com with SMTP id f12so2812880qad.8 for ; Wed, 22 Oct 2014 11:38:19 -0700 (PDT) X-Received: by 10.229.236.197 with SMTP id kl5mr33613451qcb.31.1414003099129; Wed, 22 Oct 2014 11:38:19 -0700 (PDT) Original-Received: by 10.229.202.133 with HTTP; Wed, 22 Oct 2014 11:38:19 -0700 (PDT) In-Reply-To: X-Original-Sender: olafvdspek@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of olafvdspek@gmail.com designates 2607:f8b0:400d:c00::231 as permitted sender) smtp.mail=olafvdspek@gmail.com; dkim=pass header.i=@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:14134 Archived-At: On Wed, Oct 22, 2014 at 8:29 PM, Bo Persson wrote: >> Is it really that difficult? >> If the name doesn't match an already seen file but the size does one >> could hash the contents and check the hash. >> > > It really IS that difficult. > > On my work computer I have mounts to several departmental servers (located > in different cities), some NAS devices that I don't even know where they > are, a ClearCase system on a Unix machine, and the file system on a z/OS > mainframe. Add a local hard disk, a DVD and some USB-devices, and you get a > real world system. > > How is the standard supposed to specify what a unique file means? See above > And how > useful is it for every existing compiler to support this? Quite useful, nearly 99.99% of the headers probably need an include guard or something better. -- --- 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. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposals/. .