220 21172 article Path: news.gmane.org!not-for-mail From: Ville Voutilainen Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: P0007R0: Constant View: A proposal for a std::as_const helper function template Date: Fri, 2 Oct 2015 17:45:51 +0300 Lines: 19 Approved: news@gmane.org Message-ID: References: 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 1443797163 26805 80.91.229.3 (2 Oct 2015 14:46:03 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 2 Oct 2015 14:46:03 +0000 (UTC) To: "ISO C++ Standard - Future Proposals" Original-X-From: std-proposals+bncBC5JHI7A7ALRBIFRXKYAKGQEZIBEU3Y@isocpp.org Fri Oct 02 16:45:58 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ob0-f197.google.com ([209.85.214.197]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Zi1at-0000mq-P4 for gclcip-std-proposals@m.gmane.org; Fri, 02 Oct 2015 16:45:55 +0200 Original-Received: by obqc1 with SMTP id c1sf142636423obq.2 for ; Fri, 02 Oct 2015 07:45:54 -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:content-type: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=QtbhECI/M0YszP1pwoG80nY061uH3yl0pdi0A1Dj4DU=; b=nLZ5vc2Oht67OaRJR7UrTdfA4XjVACJtW+7CR9W/OS1BXNIeFwdtPA+rKI7Z5tczrj lyoQ7SDn8KCK1GdIiev+ouFgtOluzEsJO5aATXMIY5KZNcGui6AePhMSErEAKmX0+bUv k8AjsC9uohyiqXnNWyLNz6QPaWVMYsRZSs6EIBVwG0/CGlX8QA7dO3ETCGcuxo9T18kh rYmRkRqQmtd0QRLly+21R3kUn55m/z7H/xis+/5diamh6dOOHJgqWcrBmoxoLgCMCMTM iV751BRX5Tsw35PAA13+rvxcPIaJTbSyGTO9e8vd8+MFkux6YV+PG+GCmWPNGK2pJl+d xMIg== X-Gm-Message-State: ALoCoQmG+03Z9hoe+YA093qUKYGGCln2BVkKIv1q9gq5i7/gskn/SWPwL34Wgf4bYgiXQ+1jyO+H X-Received: by 10.50.3.97 with SMTP id b1mr3929740igb.3.1443797154860; Fri, 02 Oct 2015 07:45:54 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.140.107.7 with SMTP id g7ls1650500qgf.98.gmail; Fri, 02 Oct 2015 07:45:51 -0700 (PDT) X-Received: by 10.31.131.141 with SMTP id f135mr10650014vkd.37.1443797151844; Fri, 02 Oct 2015 07:45:51 -0700 (PDT) Original-Received: from mail-vk0-x236.google.com (mail-vk0-x236.google.com. [2607:f8b0:400c:c05::236]) by mx.google.com with ESMTPS id v129si6170455vke.118.2015.10.02.07.45.51 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 02 Oct 2015 07:45:51 -0700 (PDT) Received-SPF: pass (google.com: domain of ville.voutilainen@gmail.com designates 2607:f8b0:400c:c05::236 as permitted sender) client-ip=2607:f8b0:400c:c05::236; Original-Received: by vkfp126 with SMTP id p126so61193558vkf.3 for ; Fri, 02 Oct 2015 07:45:51 -0700 (PDT) X-Received: by 10.31.133.141 with SMTP id h135mr10848631vkd.85.1443797151691; Fri, 02 Oct 2015 07:45:51 -0700 (PDT) Original-Received: by 10.103.37.195 with HTTP; Fri, 2 Oct 2015 07:45:51 -0700 (PDT) In-Reply-To: X-Original-Sender: ville.voutilainen@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of ville.voutilainen@gmail.com designates 2607:f8b0:400c:c05::236 as permitted sender) smtp.mailfrom=ville.voutilainen@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-Spam-Checked-In-Group: std-proposals@isocpp.org 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:21172 Archived-At: On 2 October 2015 at 17:38, Matthew Woehlke wrote: > While it's true that we want lifetime extension anyway, the reality is > that std::as_const *also* doesn't work without core language changes, > i.e. as a library-only solution it is incomplete. Moreover, I don't see > that it cannot be made to work at all for an rvalue of a type that is > not {copy,move}able without introducing mandatory copy elision. (The Ah, yes, the rvalue overload is returning by value, which doesn't work for forwarding cases. Then again, for forwarding cases, one can forward() so perhaps that wasn't important. -- --- 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/. .