220 11799 <6F4B3C72-9962-48DC-8527-0C89EA1B9710@gmail.com> article Path: news.gmane.org!not-for-mail From: David Krauss Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: N4078: Rvalue reference overloads for value() method returns object by value Date: Thu, 10 Jul 2014 17:03:02 +0800 Lines: 74 Approved: news@gmane.org Message-ID: <6F4B3C72-9962-48DC-8527-0C89EA1B9710@gmail.com> References: <4DA018C3-2327-4F55-B7F8-7988EC7B789A@gmail.com> <1a858a77-310b-4591-aaf5-960c40d9f5fc@isocpp.org> <66AF41C1-CB37-4311-98EA-D47DBC6068DC@gmail.com> <66c38b61-7a95-4ace-b34f-2346bb334fb9@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Content-Type: multipart/alternative; boundary="Apple-Mail=_6A25EAEC-9D24-4957-B612-65B9F7117840" X-Trace: ger.gmane.org 1404982999 7647 80.91.229.3 (10 Jul 2014 09:03:19 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 10 Jul 2014 09:03:19 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCW25A7E3QCRBTNN7GOQKGQEP6DBNFQ@isocpp.org Thu Jul 10 11:03:12 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ob0-f200.google.com ([209.85.214.200]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1X5AFz-0007dd-05 for gclcip-std-proposals@m.gmane.org; Thu, 10 Jul 2014 11:03:11 +0200 Original-Received: by mail-ob0-f200.google.com with SMTP id nu7sf7156529obb.7 for ; Thu, 10 Jul 2014 02:03:10 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:message-id:mime-version:subject:date :references:to:in-reply-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=qkD81pd9TDJOfFtCJWrCRvilBIn0zqdtCf7leMkZLAs=; b=gZooZU2B3HItxTuHciupTa7WjTTsKCOTrBokVRQcbmaW/n1i7mzifSGA13IcxAX3sG mxwB7c0ET7Eg5ka2KfUbTnwFEw5BtqmuxiS53Khwxf9WUQ2viEN8cpGKr+GgrnQRhJGT xbzntE14kSDCZt74HhLRwdxdkxNEbZ3Nb35qnr8FBvg8iFcTd6VXzIbxC+o7WW16RvQ7 YHZFUDbvmTIEU7WF5Ae1iaLH1s19gq72n/Rj4mz4+0Os8qxyLnZT+eES/RKlGMLV24QP WB9lkZx/ImYO/nnj3I+11f5W4u6eNVnAbvM1CXZAQFj+NbfmYvv4/NwB+twLKrDB4qKK TJMw== X-Gm-Message-State: ALoCoQmk7Ihz8AbssOaC+sCelmf8n0srSy+KZeHU0vo5xhqKTNsl4sFxsWzl2uLjlqr6PAUro9VR X-Received: by 10.50.171.134 with SMTP id au6mr6906046igc.7.1404982990063; Thu, 10 Jul 2014 02:03:10 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.79.195 with SMTP id l3ls1332008igx.31.canary; Thu, 10 Jul 2014 02:03:09 -0700 (PDT) X-Received: by 10.50.23.16 with SMTP id i16mr19794140igf.24.1404982989399; Thu, 10 Jul 2014 02:03:09 -0700 (PDT) Original-Received: from mail-ig0-x22b.google.com (mail-ig0-x22b.google.com [2607:f8b0:4001:c05::22b]) by mx.google.com with ESMTPS id d14si24278356icn.44.2014.07.10.02.03.09 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 10 Jul 2014 02:03:09 -0700 (PDT) Received-SPF: pass (google.com: domain of potswa@gmail.com designates 2607:f8b0:4001:c05::22b as permitted sender) client-ip=2607:f8b0:4001:c05::22b; Original-Received: by mail-ig0-f171.google.com with SMTP id l13so2446742iga.4 for ; Thu, 10 Jul 2014 02:03:09 -0700 (PDT) X-Received: by 10.50.60.41 with SMTP id e9mr20238392igr.11.1404982989245; Thu, 10 Jul 2014 02:03:09 -0700 (PDT) Original-Received: from [172.20.10.2] ([121.54.54.43]) by mx.google.com with ESMTPSA id q11sm23409808igr.7.2014.07.10.02.03.06 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 10 Jul 2014 02:03:08 -0700 (PDT) In-Reply-To: X-Mailer: Apple Mail (2.1878.6) X-Original-Sender: potswa@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of potswa@gmail.com designates 2607:f8b0:4001:c05::22b as permitted sender) smtp.mail=potswa@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:11799 Archived-At: --Apple-Mail=_6A25EAEC-9D24-4957-B612-65B9F7117840 Content-Type: text/plain; charset=ISO-8859-1 On 2014-07-10, at 5:01 PM, Ville Voutilainen wrote: > On 10 July 2014 11:58, David Krauss wrote: >> Risky micro-optimization should never be the default. If > > It's not a micro-optimization. Eliminating one move is a micro-optimization. >> forward-by-reference returns are sometimes desired for performance, then add >> them under a function name like forward_*() or provide a suitable additional >> sibling to std::forward() to handle such cases. Do not foist the hack on >> everyone. > > The standard library already "foists the hack" on everyone. For, > apparently, good > reasons. In exactly one function? std::get does not count separately for each overload, sorry. This does not set much of a precedent. -- --- 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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On 2014&= ndash;07–10, at 5:01 PM, Ville Voutilainen <ville.voutilainen@gmail.com> wrote:
On 10 July = 2014 11:58, David Krauss <potswa@gma= il.com> wrote:
Risky micro-optimization= should never be the default. If

It's not a micro-optim= ization.

Eliminating one move is a micr= o-optimization.

forward-by-reference returns are sometimes desired for performance, then = add
them under a function name like forward_*() or provide a suitable ad= ditional
sibling to std::forward() to handle such cases. Do not foist th= e hack on
everyone.

The standard library already "fo= ists the hack" on everyone. For,
apparently, good
reasons.

In exactly one function? std::g= et does not count separately for each overload, sorry. This does not= set much of a precedent.

--

---
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