220 29879 article Path: news.gmane.org!.POSTED!not-for-mail From: =?UTF-8?Q?Jonathan_M=C3=BCller?= Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: New smart pointer: CopyConstructible and CopyAssignable flavor of unique_ptr Date: Sat, 17 Dec 2016 18:48:26 +0100 Lines: 52 Approved: news@gmane.org Message-ID: References: <67a9e9ed-8748-4098-a43b-33598b516464@isocpp.org> <20161217141109.GA22645@manuel-ThinkPad-L440.localdomain> <3df7e8eb-01a0-7804-f476-504b5a25a9fe@gmail.com> <20161217170428.GA10214@manuel-ThinkPad-L440.localdomain> <20161217171633.4919375.58072.21574@gmail.com> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary=94eb2c06fa8233c2fc0543de4b30 X-Trace: blaine.gmane.org 1481996911 1933 195.159.176.226 (17 Dec 2016 17:48:31 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 17 Dec 2016 17:48:31 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCUMHC4Z6QGBB27U2XBAKGQEFJ43UUI@isocpp.org Sat Dec 17 18:48:26 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yb0-f197.google.com ([209.85.213.197]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cIJ5r-0007nA-Te for gclcip-std-proposals@m.gmane.org; Sat, 17 Dec 2016 18:48:24 +0100 Original-Received: by mail-yb0-f197.google.com with SMTP id h184sf140290961ybb.7 for ; Sat, 17 Dec 2016 09:48:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:from:date:message-id:subject: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=6/reMqHkvlRRVj99gbe4IW9ZnOFyoMJqEkYCAWzft90=; b=wS9CxkpVZ6T/VrXdfQO6EKs0WGtOBDWZtnhriwmkZwUFKi5u0tIN3Oj3BhTmuC8N7P rvtiOn2J3tpUthw7kzOYpyxa8YbhuDRZh/R6AdZHTuPjtfoXOgHOKSr8ibWNCUkqUgMb Me1JM7SXIE4GuWgHuCUT57ZmEYpyjnOj0v5wiAOiOnUKoZuzoRrBwOvd00Q/qTRphHwB wVlp2XQ+Wr0NAmdh2BBZxcXZnSCN4n48NCn4/8j1uaGpQoKltk7G/qbtOnClgIvUZ619 8Aag0Npw/3Co6WGqRaDpMVdqFq38vBvJKYSDWj8SYNoB8Q3xzADAMqRG6V+OWVVs0u76 7Lyw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject: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=6/reMqHkvlRRVj99gbe4IW9ZnOFyoMJqEkYCAWzft90=; b=GfjqmOI7JjN9T8p0+q4z2yykvDtX/M8LhNoJo/96zCgTQQWmokh8UcIjbbNWSVK9jU ZHncB6CmLxDr711eaahZX+hdKw9Gl8mpuoAc0xFhWnQs+XPMjquarJAwlT+EBl9v5Dib JqQgJ/v1ko7zEZuUBKZXOEVa3yY8TW1IU+nqbLT7IYlLRYFxoeXALGC1MvyMy9YWTRUz ktTuP0tXtJ5haDoyeFvfvTP6dD4E8yjW+fJkGwuOvMEa2p02Z5AcVDjy8AJTBFXNdp0N LJmSNpC0V1a2zkPkliAnCPz0jOUz5WKv3V37CCw8mwYW3pVd2iI0lPMTHaWwTt+sB/Q6 woJg== X-Gm-Message-State: AIkVDXIOcJpXrGz1oKO2DXNG6xutibHFkYN/M6zBGm+WKJjf3C4FBZ/V92eujIJ55Zr2uA== X-Received: by 10.129.97.84 with SMTP id v81mr2146163ywb.8.1481996908069; Sat, 17 Dec 2016 09:48:28 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.26.102 with SMTP id u35ls11150022otu.4.gmail; Sat, 17 Dec 2016 09:48:27 -0800 (PST) X-Received: by 10.55.200.132 with SMTP id t4mr543003qkl.53.1481996907320; Sat, 17 Dec 2016 09:48:27 -0800 (PST) Original-Received: from mail-qk0-x22e.google.com (mail-qk0-x22e.google.com. [2607:f8b0:400d:c09::22e]) by mx.google.com with ESMTPS id u33si6070880qte.53.2016.12.17.09.48.27 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 17 Dec 2016 09:48:27 -0800 (PST) Received-SPF: pass (google.com: domain of jonathanmueller.dev@gmail.com designates 2607:f8b0:400d:c09::22e as permitted sender) client-ip=2607:f8b0:400d:c09::22e; Original-Received: by mail-qk0-x22e.google.com with SMTP id n21so121665719qka.3 for ; Sat, 17 Dec 2016 09:48:27 -0800 (PST) X-Received: by 10.55.161.87 with SMTP id k84mr236288qke.234.1481996907035; Sat, 17 Dec 2016 09:48:27 -0800 (PST) Original-Received: by 10.55.74.202 with HTTP; Sat, 17 Dec 2016 09:48:26 -0800 (PST) Original-Received: by 10.55.74.202 with HTTP; Sat, 17 Dec 2016 09:48:26 -0800 (PST) In-Reply-To: <20161217171633.4919375.58072.21574@gmail.com> X-Original-Sender: jonathanmueller.dev@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com; spf=pass (google.com: domain of jonathanmueller.dev@gmail.com designates 2607:f8b0:400d:c09::22e as permitted sender) smtp.mailfrom=jonathanmueller.dev@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:29879 Archived-At: --94eb2c06fa8233c2fc0543de4b30 Content-Type: text/plain; charset=UTF-8 On Dec 17, 2016 18:16, "Tony V E" wrote: > > Templates. Where you don't know if T has .clone(). Cloning in C++ is typically spelled with the copy-constructor. > But generic code would assume certain properties of a copy constructor, this one does not have, as Sean Parent pointed out. So copy constructing in generic code might be harmful. -- 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. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/CAEddoJaAZkeJS9Maj2z0vYGnfuNnJZ%2BqFFdjeQyesTF5itJxHA%40mail.gmail.com. --94eb2c06fa8233c2fc0543de4b30 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

On Dec 17, 2016 18:16, "Tony V E" <tvaneerd@gmail.com> wrote:
>
> Templates. Where you don't know if T has .clone(). Cloning in C++ = is typically spelled with the copy-constructor.=C2=A0
>

But generic code would assume certain properties of a copy c= onstructor, this one does not have, as Sean Parent pointed out.

So copy constructing in generic code might be harmful.

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