220 36362 article Path: news.gmane.org!.POSTED!not-for-mail From: "mrpi via ISO C++ Standard - Future Proposals" Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Default assignment operators for std::pair and std::tuple Date: Tue, 26 Dec 2017 11:51:35 -0800 (PST) Lines: 88 Approved: news@gmane.org Message-ID: References: <4110e47f-a021-4ccc-9e03-53e4ebdb8c21@isocpp.org> <4605434.q3o9RnjlYE@tjmaciei-mobl1> <5300cf40-f7db-4eb6-ad36-4742855124ae@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_19128_1057704000.1514317895830" X-Trace: blaine.gmane.org 1514317781 23176 195.159.176.226 (26 Dec 2017 19:49:41 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 26 Dec 2017 19:49:41 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBDH2LIF7UEOBBSGQRLJAKGQEMIXKSLQ@isocpp.org Tue Dec 26 20:49:37 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ua0-f199.google.com ([209.85.217.199]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1eTvEG-0005f1-73 for gclcip-std-proposals@m.gmane.org; Tue, 26 Dec 2017 20:49:36 +0100 Original-Received: by mail-ua0-f199.google.com with SMTP id a2sf459316uak.0 for ; Tue, 26 Dec 2017 11:51:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:message-id:in-reply-to:references:subject:mime-version :x-original-sender:reply-to:precedence:mailing-list:list-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe; bh=uNru1aNK7EpKwlJvZp6Uj6Cww7MqYZecotJ/reJsWy4=; b=YHKxgReidNFlXMqVKJOpvt8vkTjgGXMRjDWTHpLKBIGRwYqpxiGJ2/PnFpSoqApPTI DlC5H8hR/dEmzOd1WFhJa/eL6wzI2ntFIcwNtbgvOkMJgM20qmo71UB2Tq3hpa4lkY6p yqQgs//jlTyeZOcsaXyQFuvIvvUr2mwMolOhn09IB5qlBgHPxqZvbl1aA79G4EOlb7LR HPK2PH9ni/9xCuQyNBJW34JUh7v1riSMRHw71F0xmy7lq5Kq/H7WcGP+H/iG0yRnOLY1 GJWUQ6ABCqfP62/Gi4KZ9BRxlbreOYTH23/k0gKjPJbweKtYoLt1VvrTLlmfDhdBG9uA Gqng== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:message-id:in-reply-to:references :subject:mime-version:x-original-sender:reply-to:precedence :mailing-list:list-id:x-spam-checked-in-group:list-post:list-help :list-archive:list-subscribe:list-unsubscribe; bh=uNru1aNK7EpKwlJvZp6Uj6Cww7MqYZecotJ/reJsWy4=; b=eA5GhdL5Fs3brjZ6utjPQgT83vh6ic0qE1LRLcOOX89kWZfj49mtRj7oCH+b/Ga4ab 0zOR9DAONetlW19AOrVEhzVYmdQJy6tovZT+PD9dkyYW30pUui0Kzm/TA5cK7Y20ioy7 FujVa+7j11Xb0tES79+mlZddZ6/2AJnNL+gZ3EvWo7pHDwv1wd2oNtonI8IuN7cMLZZ5 3pegOsw/efwLj+hrmRpYgeF70ilu4LBV926InxoG2IXwXczxK4Gz1JE+EZVJVmhjRlkP MIpTctiFw2cXc36m2k80CD7dB8ormr4egxzof41IFwrgoSN2cft/eCH4v9fQ4x26Npy0 LL/Q== X-Gm-Message-State: AKGB3mJYCOoVhDodWFZTSRi2DhE2t001gqB+3dm80Os0MCkAWraHSit+ gOBrholbvd7FLHoNCjLr06YF0A== X-Google-Smtp-Source: ACJfBousxsaBgo4n81m3uE+ovwICPcnEjWIa/jZ7zHTOjzLA0SyMqqFY4qjkrWDGXyuPAU8w6tya5A== X-Received: by 10.31.63.211 with SMTP id m202mr11888851vka.14.1514317898504; Tue, 26 Dec 2017 11:51:38 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.31.168.12 with SMTP id r12ls3158771vke.13.gmail; Tue, 26 Dec 2017 11:51:36 -0800 (PST) X-Received: by 10.31.158.84 with SMTP id h81mr2442055vke.6.1514317896278; Tue, 26 Dec 2017 11:51:36 -0800 (PST) In-Reply-To: X-Original-Sender: mrpi@google.com X-Original-From: mrpi@google.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org 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:36362 Archived-At: ------=_Part_19128_1057704000.1514317895830 Content-Type: multipart/alternative; boundary="----=_Part_19129_1020130931.1514317895830" ------=_Part_19129_1020130931.1514317895830 Content-Type: text/plain; charset="UTF-8" Doesn't the same argument about optionals and variants apply? Just recently std::optional and std::variant weren't yet made trivially copyable (nor have any recent draft of the standard accepted it yet). What I'm asking about is doing the same for std::pair and std::tuple. And furthermore, what sort of problems would pop up from enforcing std::tuple to be trivially copyable? On Tuesday, December 26, 2017 at 11:36:01 AM UTC-8, Ville Voutilainen wrote: > > On 26 December 2017 at 20:37, mrpi via ISO C++ Standard - Future > Proposals > wrote: > > How would it be an ABI break/change if the standard never specified if > it > > was trivially copyable or not? In the first place, the discrepancy > between > > > The point is that tuple is not a trivially copyable type in > libstdc++ today. Making it trivially copyable > would be an ABI break. > -- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. 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Doesn't the same argument about=C2=A0optionals and = variants=C2=A0apply? Just recently std::optional and std::variant weren= 't yet made trivially copyable (nor have any recent draft of the standa= rd accepted it yet). What I'm asking about is doing the same for std::p= air and std::tuple.

And furthermore, what sort of proble= ms would pop up from enforcing std::tuple<int> to be trivially copyab= le?

On Tuesday, December 26, 2017 at 11:36:01 AM UTC-8, Ville Voutil= ainen wrote:
On 26 December 201= 7 at 20:37, mrpi via ISO C++ Standard - Future
Proposals <std-pr...@isocpp.org> wrote:
> How would it be an ABI break/change if the standard never specifie= d if it
> was trivially copyable or not? In the first place, the discrepancy= between


The point is that tuple<int> is not a trivially copyable type in
libstdc++ today. Making it trivially copyable
would be an ABI break.

--
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