220 9505 article Path: news.gmane.org!not-for-mail From: Ville Voutilainen Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Feedback on N3949 - Scoped Resource - Generic RAII Wrapper for the Standard Library Date: Mon, 3 Mar 2014 09:37:06 +0200 Lines: 47 Approved: news@gmane.org Message-ID: References: <67F4693D-4473-4700-A60E-8C434D55E226@gmail.com> <046BD86D-F427-492C-8F6A-14F448806E3D@gmail.com> <904A2E2E-8F3B-4787-B368-8C5CC888F4B7@gmail.com> <7B6D9AC1-7C06-4300-9A27-9D465F1BDB24@gmail.com> 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 1393832220 18169 80.91.229.3 (3 Mar 2014 07:37:00 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 3 Mar 2014 07:37:00 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBC5JHI7A7ALRBIXC2CMAKGQE6IYOJII@isocpp.org Mon Mar 03 08:37:09 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-oa0-f72.google.com ([209.85.219.72]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1WKNQy-0002T4-I9 for gclcip-std-proposals@m.gmane.org; Mon, 03 Mar 2014 08:37:08 +0100 Original-Received: by mail-oa0-f72.google.com with SMTP id g12sf19561242oah.7 for ; Sun, 02 Mar 2014 23:37:07 -0800 (PST) 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=E4NaZznf6JqR1dw9efHNQ/duPjY9/speItu7NMkUVxY=; b=iPrROzd69tAhrxA61cNbeJMBajdbLbSLOvotys31vzx6ADq8JHBMKyQvmw+jkHHRmq hPUdBscvvJJu/FG111G3IzBFLElNp4t0BG7nsogT/VMC0hybqrKmSljJvROKLbQ5H2H3 GzrNLgk7IEpvHruUo+sVn7CIcucLJ1ZY+PCvMKk2+r/Ld2bBlANfMnuJI3H3i2iaSUi/ Z85evmm5kv2OKBCrpRtyuRM8Gskn1RsGjU44Vyln9Dp1FzEXxtPyENtGlPqE9Je3kPFJ /ie5zngoiHbqMuzcw9bv1JA9cAXjcg1SmqtVcLRKPBRlq/TnNiVJkoffbSPJX1PVOcMq /NeA== X-Gm-Message-State: ALoCoQlndyLFKzsOvhlwr2dZTi7+l1lbBQrjCtiK3ou7Yv4qF0GXPxZiB+nrCShNbl1Wjtr6iL0s X-Received: by 10.43.125.196 with SMTP id gt4mr8416438icc.32.1393832227361; Sun, 02 Mar 2014 23:37:07 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.140.42.14 with SMTP id b14ls2081959qga.47.gmail; Sun, 02 Mar 2014 23:37:06 -0800 (PST) X-Received: by 10.224.44.8 with SMTP id y8mr21429911qae.44.1393832226479; Sun, 02 Mar 2014 23:37:06 -0800 (PST) Original-Received: from mail-qg0-x232.google.com (mail-qg0-x232.google.com [2607:f8b0:400d:c04::232]) by mx.google.com with ESMTPS id f6si5315563qap.152.2014.03.02.23.37.06 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sun, 02 Mar 2014 23:37:06 -0800 (PST) Received-SPF: pass (google.com: domain of ville.voutilainen@gmail.com designates 2607:f8b0:400d:c04::232 as permitted sender) client-ip=2607:f8b0:400d:c04::232; Original-Received: by mail-qg0-f50.google.com with SMTP id z60so10392341qgd.9 for ; Sun, 02 Mar 2014 23:37:06 -0800 (PST) X-Received: by 10.224.22.65 with SMTP id m1mr29259qab.103.1393832226364; Sun, 02 Mar 2014 23:37:06 -0800 (PST) Original-Received: by 10.224.65.6 with HTTP; Sun, 2 Mar 2014 23:37:06 -0800 (PST) In-Reply-To: <7B6D9AC1-7C06-4300-9A27-9D465F1BDB24@gmail.com> 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:f8b0:400d:c04::232 as permitted sender) smtp.mail=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-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:9505 Archived-At: On 3 March 2014 09:08, David Krauss wrote: >> I don't think such iterators should have such an operator->. >> [iterator.requirements.general]/1 says >> "All iterators i for which the expression (*i).m is well-defined, support >> the >> expression i->m with the same semantics as (*i).m. " >> For the iterators in case here, (*i).m is not well-defined, so they >> shouldn't >> support operator->. > The standard simply doesn't discuss the implementation of iterator > operator->. It does not require the function to exist, but neither does it > forbid it, and it's such a minor QOI issue that nobody cares. SFINAE is just Yes, what the quoted passage say doesn't really define whether the operator is or is not there, unfortunately. > a hoop to jump through here, and it makes implementation bugs more likely. Implementations have to perform such "does not participate in overload resolution" conditioning in so many places that this is a non-issue. Weighing the pointless presence of a certainly-ill-formed operator versus the implementation complexity, I'd say the restrictions for operator-> and operator* are just fine, and should be specified correctly. > You could say the same for operator*; it exists for an int resource but > using it results in an ill-formed implicit specialization. This also has the Except that it doesn't exist for an int resource according to the current proposal. > effect of making the class impossible to explicitly instantiate, which may > be a real issue. All the more reason to avoid always-ill-formed member functions. Thus far I've heard zero good reasons to include them unconditionally. -- --- 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. 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