220 34961 <72ef3209-6749-4246-9c5a-1549557ceb5a@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: Mingxin Wang Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Idea about "std::pmr::memory_resource" Date: Mon, 16 Oct 2017 04:55:41 -0700 (PDT) Lines: 117 Approved: news@gmane.org Message-ID: <72ef3209-6749-4246-9c5a-1549557ceb5a@isocpp.org> References: <0a8293b4-3246-47a5-9881-bc1ca4b91772@isocpp.org> <07ddb1f6-d3af-43df-bf96-8975c1ab4313@isocpp.org> <2e191a96-1952-479b-b78b-22e31f8e03de@isocpp.org> <0e37b5ae-64f6-4a8a-86bd-f44b119ed40a@isocpp.org> <15f8c5ba-3a6a-4441-9620-92e157c66094@isocpp.org> <26fe4cb4-98ca-41cc-ac96-5c51851799d1@isocpp.org> <784ffce8-ace7-449d-a13d-a99d7336117a@isocpp.org> <6d0ad98b-87d5-43dd-ac54-2b7d3e03e31b@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_17448_1378561949.1508154941561" X-Trace: blaine.gmane.org 1508154956 27062 195.159.176.226 (16 Oct 2017 11:55:56 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 16 Oct 2017 11:55:56 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBDNMBNHJWIGBBPV4SLHQKGQEOD6UD4A@isocpp.org Mon Oct 16 13:55:52 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ua0-f198.google.com ([209.85.217.198]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1e43zc-0004gx-AP for gclcip-std-proposals@m.gmane.org; Mon, 16 Oct 2017 13:55:36 +0200 Original-Received: by mail-ua0-f198.google.com with SMTP id e46sf7557518uaa.6 for ; Mon, 16 Oct 2017 04:55:43 -0700 (PDT) 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=TOxurWqObPZ1y9ccqZwA68CmdSh3renfLckENoWDA7U=; b=b7v97dLKSSh59e/PrndfXlHCmnqLOWCbMjauYQQOloIg/B2JRiSyM/S7jmTZ7iKiap mALjeroJsjGBbMkPGNCj0H5YDLRa0ynIObct0okJhWBUMevJNtHq+kTOTWdAe+qnPhKr YO0jltFdNjU6MJiO/ea6ko+LAgnA16j9yPuF3yQgDbkZrbKG3MINf/fcgxQPzSFh6R+y fREv160NsVMzeE5357UB30ZhvRbs1O6Oj7AYdf35AAK2u9dL8cJdmoF6PZrFhbZ1WJKs VSsnNzYsmDd3aW2mUkIYVvUzUqOii/XO9W9ldvjVPZMLumCdfq01/gQm2QmUNpcNBfR4 2xQQ== 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=TOxurWqObPZ1y9ccqZwA68CmdSh3renfLckENoWDA7U=; b=IXNe8X90yIv3Q2WRMrodHXBWjp4xOglJK7F2NbkyVmBsHmoSNwg5zyYEirXk1tx37N mL9+gANL/06UbHv8BcIoohEZOup9BgayGichThXiP8pq7DDDXKKhLYnNcAQNdwV9upUl NpGvxiz3KUrh6gv4ChYaTlrfnzPEIwzKAhmhfnEt9NPHgscVMpRqqXOa/CNn/MqlF8Fn QCA8Q//r/XlJPb+fs7whImapb5JXZzqoQ5B5NFB56r3QuskLZF6TNQLJybO0MU/YTCRV 51cZYkX/JQRQYc61yvITQ3UqH5Fw10i5E0yZSzfIOTi9bMGXSZgIjmRwxB1D38Wvp640 fKzQ== X-Gm-Message-State: AMCzsaUO7eNbNRzHoILTvgMSWl8MFJkR8grt2N6cmOO06KU8z3K2mC8x s3RniEPJuTY1wLNSZR6CeHuQDA== X-Google-Smtp-Source: AOwi7QCLV9nu/KMaQraUFq/RWjtZCNZAIJ/gxzYV7AgVKpt+wkHnzNEvmvfsRicZyUv16JMJJ7MkCw== X-Received: by 10.176.17.201 with SMTP id q9mr5099719uac.109.1508154943444; Mon, 16 Oct 2017 04:55:43 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.159.56.51 with SMTP id p48ls1526294uad.9.gmail; Mon, 16 Oct 2017 04:55:42 -0700 (PDT) X-Received: by 10.31.168.133 with SMTP id r127mr390271vke.8.1508154942156; Mon, 16 Oct 2017 04:55:42 -0700 (PDT) In-Reply-To: <6d0ad98b-87d5-43dd-ac54-2b7d3e03e31b@isocpp.org> X-Original-Sender: wmx16835vv@163.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:34961 Archived-At: ------=_Part_17448_1378561949.1508154941561 Content-Type: multipart/alternative; boundary="----=_Part_17449_7965529.1508154941562" ------=_Part_17449_7965529.1508154941562 Content-Type: text/plain; charset="UTF-8" On Monday, October 16, 2017 at 6:55:41 PM UTC+8, Aleksey Loginov wrote: > Let's look at a more applied example: > > template > struct static_resource : memory_resource { aligned_storage_t m_data; > }; > > template > struct my_any; > > > my_any x1; > my_any> x2; > > x1 = 1; > x2 = x1; > > assert(x2 == 1); > > > How can you do this without RTTI? > What is the semantics of `x2 == 1`? There is no definition about `operation==(...)` in the class `std::any`, and this expression is ill-formed if `x2` is a value of `std::any`. Do you mean that `any::operator==(const any&)` shall be added to the standard? If so, I suggest that you should illustrate your motivation and provide reasonable semantics. Mingxin Wang -- 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/72ef3209-6749-4246-9c5a-1549557ceb5a%40isocpp.org. ------=_Part_17449_7965529.1508154941562 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On Monday, October 16, 2017 at 6:55:41 PM UTC+8, Aleksey L= oginov wrote:
Let's look at a more applied example:

<= span style=3D"color:#008">template<size_t Siz= e> <= br>struct static_resource : memory_resource { aligned_storage_t<= Size&g= t; m_data; };=

template<typename MR>
struct= =C2=A0my_any;


my_any<default_memory_resource> x1;<= /div>
my_any<static_resource<32>> x2;

= x1 =3D 1;
x2 =3D = x1;

assert(x2 =3D=3D 1);


How can you=C2= =A0do this without RTTI?

= What is the semantics of `x2 =3D=3D 1`? There is no definition about `opera= tion=3D=3D(...)` in the class `std::any`, and this expression is ill-formed= if `x2` is a value of `std::any`. Do you mean that `any::operator=3D=3D(co= nst any&)` shall be added to the standard? If so, I suggest that you sh= ould illustrate your motivation and provide reasonable semantics.

Mingxin Wang

--
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+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/72ef3209-6749-4246-9c5a-1549557ceb5a= %40isocpp.org.
------=_Part_17449_7965529.1508154941562-- ------=_Part_17448_1378561949.1508154941561-- .