220 29832 <20161216124658.4919375.82156.21506@gmail.com> article Path: news.gmane.org!.POSTED!not-for-mail From: Tony V E Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: New smart pointer: CopyConstructible and CopyAssignable flavor of unique_ptr Date: Fri, 16 Dec 2016 07:46:58 -0500 Lines: 68 Approved: news@gmane.org Message-ID: <20161216124658.4919375.82156.21506@gmail.com> References: <13702f32-32c2-447f-9996-3624fd678675@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Trace: blaine.gmane.org 1481892430 3464 195.159.176.226 (16 Dec 2016 12:47:10 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 16 Dec 2016 12:47:10 +0000 (UTC) To: =?utf-8?q?Jonathan_M=C3=BCller?= , std-proposals@isocpp.org, Jonathan Coe , Jonathan Coe Original-X-From: std-proposals+bncBCUZ5QWKNQIMJRGPYICRUBCXTVV6Y@isocpp.org Fri Dec 16 13:47:04 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yb0-f200.google.com ([209.85.213.200]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cHruc-0007WV-Cb for gclcip-std-proposals@m.gmane.org; Fri, 16 Dec 2016 13:46:58 +0100 Original-Received: by mail-yb0-f200.google.com with SMTP id h184sf104726444ybb.7 for ; Fri, 16 Dec 2016 04:47:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=mime-version:content-transfer-encoding:message-id:date:subject:from :in-reply-to:references:to: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=72KSsS7m74lrXViF0fJGqF1xHnDPcU1Jj/bCkztGNQA=; b=M35vfTiBCKa0G6+tZuINyO1eQeM5eGowtofGuZfcsVMsS8wiNtdVqemum4JjQJek9z V7wH7S2rmJvCMqHwYHl0Ber2PfdT0KW/j2RV3twpRoegteAb4Zha3gJq/Egn9+gX+tCv GLjg7xDytHOO8Awvxb9RQQLHYAvci1iDLv7YFWNozawBRPjxKvpZcmvj0yDuG+PRFBIq hOWaPwMbmmbJBymABTSEuChELDi90/ubAneKuEbPbBKsuHhDNnD6vIxW/DpUtOkGNG1e mxPNfW+ynnP0deZiihpZ3gHbLNUw2Rt7xLjGYYh+dcYMzWjXepRVnR0rTa7bsUUmdoTv PfnQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:content-transfer-encoding :message-id:date:subject:from:in-reply-to:references:to :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=72KSsS7m74lrXViF0fJGqF1xHnDPcU1Jj/bCkztGNQA=; b=fIbPeaWkC7wV99DsdEXTg0eifTTwFZQ/xdDdo9ZXgluqJp9jhUe9XpA21MIHnrj6HW H4wFn6gaFJf9gHB/lH2ND1rnmLYdUseIjVBhu8uWKElRazKAD/puO/5nNyxRzLWtfKW5 zQXSXhImYvA3ZiTDqcBOmtXqzmhogDGlIoHOQw+TYvrTPi34nxW0str6bV0Z0uHIHOWZ v5xz5hfLk/pJZfyOFiuqZu1qXyIWo91kTBFtvzj8RplsdoTn07SZ9FFSMXQHUD8oEVLQ ktKhNhwFwDL9CGIqe0XppqCQFPICm9/ZxUphOfwzALC25YkkkHUlSXP+7OBFqEV/USRz VqZ X-Gm-Message-State: AKaTC02ywdwlMFvMmkahneHRf0/Y0Jyu8/gXwy8WjW0K7kXp41mCy4RnzbfWpz6vZhpEhA== X-Received: by 10.129.135.133 with SMTP id x127mr643160ywf.164.1481892422575; Fri, 16 Dec 2016 04:47:02 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.36.117.7 with SMTP id y7ls548589itc.0.gmail; Fri, 16 Dec 2016 04:47:00 -0800 (PST) X-Received: by 10.107.17.105 with SMTP id z102mr2893226ioi.165.1481892420265; Fri, 16 Dec 2016 04:47:00 -0800 (PST) Original-Received: from mail-it0-x242.google.com (mail-it0-x242.google.com. [2607:f8b0:4001:c0b::242]) by mx.google.com with ESMTPS id 5si5860665iow.0.2016.12.16.04.47.00 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 16 Dec 2016 04:47:00 -0800 (PST) Received-SPF: pass (google.com: domain of tvaneerd@gmail.com designates 2607:f8b0:4001:c0b::242 as permitted sender) client-ip=2607:f8b0:4001:c0b::242; Original-Received: by mail-it0-x242.google.com with SMTP id b123so2453685itb.2 for ; Fri, 16 Dec 2016 04:47:00 -0800 (PST) X-Received: by 10.36.66.143 with SMTP id i137mr3311564itb.43.1481892420031; Fri, 16 Dec 2016 04:47:00 -0800 (PST) Original-Received: from [127.0.0.1] ([74.15.44.73]) by smtp.gmail.com with ESMTPSA id k130sm1251840ita.20.2016.12.16.04.46.58 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 16 Dec 2016 04:46:58 -0800 (PST) X-Mailer: BlackBerry Email (10.3.2.2876) In-Reply-To: X-Original-Sender: tvaneerd@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com; spf=pass (google.com: domain of tvaneerd@gmail.com designates 2607:f8b0:4001:c0b::242 as permitted sender) smtp.mailfrom=tvaneerd@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:29832 Archived-At: It sounds to me like this may be another difference between clone_ptr and p= olymorphic value. And more reason to have both. Sent=C2=A0from=C2=A0my=C2=A0BlackBerry=C2=A0portable=C2=A0Babbage=C2=A0Devi= ce =C2=A0 Original Message =C2=A0 From: Jonathan M=C3=BCller Sent: Friday, December 16, 2016 7:36 AM To: std-proposals@isocpp.org Reply To: std-proposals@isocpp.org Subject: Re: [std-proposals] New smart pointer: CopyConstructible and CopyA= ssignable flavor of unique_ptr On 16.12.2016 13:25, Jonathan Wakely wrote: > p0201r1 deals with that problem, which is why it's a better approach. On 16.12.2016 13:28, Ville Voutilainen wrote: > Like the proposed std::indirect? I got the impression that its latest > feedback was to move it > closer to value semantics of a polymorphic type. Yeah, exactly. I like `std::indirect`, it behaves like a `T` and has consistent semantics. > But I do, otherwise I wouldn't have chosen a cloned_ptr. Alright, hard to argue with that and I get your arguments. I just don't think that's particularly "clean". If the type wasn't polymorphic you'd embed it as a member directly, so copying will copy all members and moving will move all members. But if you change it to use a polymorphic type you use a cloning_ptr, so copy will still copy everything but moving will suddenly leave the=20 type with an "empty" member? I wouldn't like using that struct with that change. There might be a possible use case for cloning_ptr, but I don't think its as a member. And if you don't use it is a member, you don't need a copy constructor but can use a free function. > All pointers are a mix between "optional" and something else since > they can be null. And that's > just fine for many cases. I meant on a semantic point of view: mix between value semantics and=20 ownership transfer. --=20 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 e= mail to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. To view this discussion on the web visit https://groups.google.com/a/isocpp= ..org/d/msgid/std-proposals/c8c29792-37a9-2eb1-1a5e-69ccfe247661%40gmail.com= .. --=20 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 e= mail to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. To view this discussion on the web visit https://groups.google.com/a/isocpp= ..org/d/msgid/std-proposals/20161216124658.4919375.82156.21506%40gmail.com. .