220 9823 article Path: news.gmane.org!not-for-mail From: Johannes Schaub Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: auto variable templates? Date: Sun, 16 Mar 2014 01:13:19 +0100 Lines: 43 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=ISO-8859-1 X-Trace: ger.gmane.org 1394928793 2577 80.91.229.3 (16 Mar 2014 00:13:13 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 16 Mar 2014 00:13:13 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCQPNCEZSQNBBIOZSOMQKGQEDOCEDLY@isocpp.org Sun Mar 16 01:13:24 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-pb0-f72.google.com ([209.85.160.72]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1WOyhf-00067i-EO for gclcip-std-proposals@m.gmane.org; Sun, 16 Mar 2014 01:13:23 +0100 Original-Received: by mail-pb0-f72.google.com with SMTP id jt11sf10188951pbb.3 for ; Sat, 15 Mar 2014 17:13:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20120113; h=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=cnOb1fpYYOZTahpf2wy0tnpulw+npWnEE7GRthYMYFg=; b=zOdXdzNHV1XfCYdg9wvK1EiSY81V9oonMq82FjoQDQzSNPUbjGhb0AY9NUjqym/CxX ftmDe390osfoLNRghBbcSjQKndw1usMxE6LKcRPzupEJm8Ay3xobhHzaiBtq6oqKgFUC M1MCnONPGupuA3zkNWnqnF4fG4cqYgrfbKqSdraR6OjCQZ4sVHgpoZoLpyth9aCMQbV/ 3omei/x2rdS7a5aMN54KG4rq9ECzOQ0Tod1dPNlbmVoUPgMdbK9Xw4D7qN7Cxhy2tq0b kG+q+3EgfkLFeubavgi/pkvD9kFx4KQy6LDY5D8Bbz45ENbeRwHvFP7gzZ6MiIaNiMvB 7MdQ== 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=cnOb1fpYYOZTahpf2wy0tnpulw+npWnEE7GRthYMYFg=; b=NVbDujfXwWr1bY541vMfKP11F7iAG8eY9RTUw8x+mrByCoxRWsjrde3uh2rmp58Cwb xZdRi4PpFk2FkbDRxbw3uCrSUZVGlR4ImHvueUzdV/2D0DFIsYcm/Ez0csd8F4qWjorx q6gPw6zRTuUs14jpl/Y477hTS6PG9xBuwQrwh6Hp6q+sehIq87YIYDhED6u+JmBA2kvt 6w3fU8ov+uO4+cCZiDmqVpQhhXS3h4Y5lLhdY8nYj9mdALqDeKzBmxTqvW+ZYE+TAt/3 m56GzqfcNt/cg77vs6ovJ3MoZVQQNX+st9vXQS2PMXaSO00ihn9L+tnE0FlLIiepMCWy Ovbg== X-Gm-Message-State: ALoCoQl/TRSF+tZ8xK/PaXVc0F8UsyzFN3b5H5h6BYFI/wpVh5do67Ha5ATcX/Exl8TnH91kHQcC X-Received: by 10.66.142.131 with SMTP id rw3mr6188366pab.18.1394928802306; Sat, 15 Mar 2014 17:13:22 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.43.167 with SMTP id x7ls358026igl.28.canary; Sat, 15 Mar 2014 17:13:20 -0700 (PDT) X-Received: by 10.68.215.68 with SMTP id og4mr17290066pbc.112.1394928800722; Sat, 15 Mar 2014 17:13:20 -0700 (PDT) Original-Received: from mail-pb0-x229.google.com (mail-pb0-x229.google.com [2607:f8b0:400e:c01::229]) by mx.google.com with ESMTPS id gr2si6826188pac.406.2014.03.15.17.13.19 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sat, 15 Mar 2014 17:13:19 -0700 (PDT) Received-SPF: pass (google.com: domain of schaub.johannes@googlemail.com designates 2607:f8b0:400e:c01::229 as permitted sender) client-ip=2607:f8b0:400e:c01::229; Original-Received: by mail-pb0-f41.google.com with SMTP id jt11so4163431pbb.14 for ; Sat, 15 Mar 2014 17:13:19 -0700 (PDT) X-Received: by 10.67.5.131 with SMTP id cm3mr17624360pad.92.1394928799630; Sat, 15 Mar 2014 17:13:19 -0700 (PDT) Original-Received: by 10.68.216.97 with HTTP; Sat, 15 Mar 2014 17:13:19 -0700 (PDT) In-Reply-To: X-Original-Sender: schaub.johannes@googlemail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of schaub.johannes@googlemail.com designates 2607:f8b0:400e:c01::229 as permitted sender) smtp.mail=schaub.johannes@googlemail.com; dkim=pass header.i=@googlemail.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:9823 Archived-At: 2014-03-16 0:38 GMT+01:00 Richard Smith : > On Sat, Mar 15, 2014 at 1:46 PM, Andrew Tomazos > wrote: >> >> Is the following supposed to be ill-formed according to the current draft? >> >> template constexpr auto X = 42; >> >> int main() >> { >> static_assert(X == 42, ""); >> } >> >> >> [dcl.spec.auto]/4 says that auto is allowed when declaring variables in >> namespace-scope, but doesn't explicitly say in variable templates - >> consequently this is ill-formed. > > > A specialization of a variable template is a variable, so this is allowed. > I don't understand this reason. The following is not a specialization of a variable template, is it? template constexpr auto X = 42; The Standard says in 7.1.6.4p6, "A program that uses auto or decltype(auto) in a context not explicitly allowed in this section is ill-formed." The section does not explicitly allow "auto" for variable templates. Why does it matter that the specialization of that template is a variable? -- --- 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/. .