220 31252 article Path: news.gmane.org!.POSTED!not-for-mail From: Oliver Kowalke Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: P0534: call/cc, type safety and exceptions Date: Wed, 1 Mar 2017 13:51:19 +0100 Lines: 236 Approved: news@gmane.org Message-ID: References: <3a57e294-7254-4358-828d-c9f7757f5295@isocpp.org> <9deccbda-26ca-4ad8-a579-1feb674676a6@isocpp.org> <69ee11fb-5cd0-4e1e-8c61-2792fe062003@isocpp.org> <7209130d-c572-4097-94a7-d92dcef0f354@isocpp.org> <0705083b-2e6f-46e9-b624-26ca0b9894ea@isocpp.org> <7bad6d77-7385-462d-9d10-4774bf97ae88@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary=94eb2c1989ee15c5880549aac68b X-Trace: blaine.gmane.org 1488372711 13829 195.159.176.226 (1 Mar 2017 12:51:51 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 1 Mar 2017 12:51:51 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCLZHP5J7MHRBXEH3PCQKGQEGLYMZMQ@isocpp.org Wed Mar 01 13:51:43 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yw0-f197.google.com ([209.85.161.197]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cj3jD-0002QW-M6 for gclcip-std-proposals@m.gmane.org; Wed, 01 Mar 2017 13:51:36 +0100 Original-Received: by mail-yw0-f197.google.com with SMTP id r137sf73289041ywg.0 for ; Wed, 01 Mar 2017 04:51:42 -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=hAhkUvtFRFdzQUAYM0vbrDO1ft6WenbG/owB/TkC8no=; b=EInjMYIuw9H1CjrmAKUM9F+3MtSTqYJuAJV6WgKKM957Y10VOPtW8gv0EHr5bMR6mG TLn/1Q3zyK4SfceR7U7T8JMnSv1syfuUyyA7auN4Dx4IqR8hWg5mTJQEEyiryXSTPygq VHo11KOR9bIavFQOTPwCmnGLtcxUQ9T2e/TMyGZUgZiQMKyLGazqjarjYXCHy3dJlQVh 2zpSDkaChJzVeaQGV1uJrRQeWM29bxBYMkZTEn7ycRkf0jg439hZdvBcLduiO1jlkRyW 5xF8Rj7BvUXjhtDGNL+OcjaRsq8WBsHUHylTLbBKpJP/PJfcJSXMc3urRrlpvmFmkrS/ m2yg== 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=hAhkUvtFRFdzQUAYM0vbrDO1ft6WenbG/owB/TkC8no=; b=aWMkE3C4lin8p+dkxLVI+SX3DPP+Aqsa048cjWM2Y9ff3eiGSiWJeSBbD9espgoWfL AVSYau78eyYfRcjRRhXQ786q3ekXxxyx5HeRvBQL25QGTj5Nw3NBRrj1SV465drcZZwb q0icZtn2H3RekLHRi2/93CpPYtUC0fsEM5C26+5nBRjCC8cKOPIkBFeUnCcxrWy/CMrq lkidbtmLi8bWviE2TLSIbosnt5TAP3xF2bNQvG5uDU7qdkGvcZxwUSVzc++Ob9HLXvVH pxQAWmKrODM2oSaBH+fVGClR1Pz6yeo1++SsTabujVRj1Rf6bCBl0JOGPhLaoYcyBPaV 6xsQ== X-Gm-Message-State: AMke39n9y84WeiWYMx1KUl4V1XKlDx3BLn0IrS/kfMQ+Iy426S6Hslwz8kWbz/m4OgMZMA== X-Received: by 10.129.73.1 with SMTP id w1mr2645118ywa.106.1488372701409; Wed, 01 Mar 2017 04:51:41 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.39.226 with SMTP id c89ls1878486otb.2.gmail; Wed, 01 Mar 2017 04:51:40 -0800 (PST) X-Received: by 10.129.132.140 with SMTP id u134mr3333097ywf.264.1488372700688; Wed, 01 Mar 2017 04:51:40 -0800 (PST) Original-Received: from mail-yw0-x230.google.com (mail-yw0-x230.google.com. [2607:f8b0:4002:c05::230]) by mx.google.com with ESMTPS id y3si575143ywe.458.2017.03.01.04.51.40 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 01 Mar 2017 04:51:40 -0800 (PST) Received-SPF: pass (google.com: domain of oliver.kowalke@gmail.com designates 2607:f8b0:4002:c05::230 as permitted sender) client-ip=2607:f8b0:4002:c05::230; Original-Received: by mail-yw0-x230.google.com with SMTP id s15so7499703ywg.0 for ; Wed, 01 Mar 2017 04:51:40 -0800 (PST) X-Received: by 10.37.160.68 with SMTP id x62mr3128749ybh.74.1488372700134; Wed, 01 Mar 2017 04:51:40 -0800 (PST) Original-Received: by 10.129.173.21 with HTTP; Wed, 1 Mar 2017 04:51:19 -0800 (PST) In-Reply-To: X-Original-Sender: oliver.kowalke@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com; spf=pass (google.com: domain of oliver.kowalke@gmail.com designates 2607:f8b0:4002:c05::230 as permitted sender) smtp.mailfrom=oliver.kowalke@gmail.com; dmarc=pass (p=NONE sp=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:31252 Archived-At: --94eb2c1989ee15c5880549aac68b Content-Type: text/plain; charset=UTF-8 Transfer run(Transfer t) { Ctx from{ t }; auto recovery = from.t.fctx; try { Ctx cc = std::invoke(f, std::move(from)); return { std::exchange(cc.t.fctx, nullptr), nullptr }; } catch (ForcedUnwind const&) { throw; } catch (...) { except = std::current_exception(); return { recovery, nullptr }; } } no matter what the code will not work - you have no guarantee that 'recovery' is still valid in the catch clause as I explained the stack 'recovery' is pointing to might be invalidated during execution of 'f' -- 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/CA%2Bwfc190izx%2BMhdq0QnHXt2YfcGjMTGA8mHFAN%3DTigC0UXcdUQ%40mail.gmail.com. --94eb2c1989ee15c5880549aac68b Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
=C2=A0=C2=A0=C2=A0 Transfer run= (Transfer t)
=C2=A0 =C2= =A0 {
=C2=A0 =C2=A0 =C2= =A0 Ctx from{ t };
=C2=A0 =C2=A0 =C2=A0 auto recovery = =3D from.t.fctx;
=C2=A0 =C2=A0 = =C2=A0 try
=C2=A0 =C2=A0 = =C2=A0 {
=C2=A0 =C2=A0 = =C2=A0 =C2=A0 Ctx cc =3D std= ::invoke(f, std::move(from));
=C2= =A0 =C2=A0 =C2=A0 =C2=A0 return { std::exchange(= cc.t<= span class=3D"gmail-m_-4274184064257848844styled-by-prettify" style=3D"colo= r:rgb(102,102,0)">.fctx, nullptr), nullptr };
=C2=A0 =C2=A0 = =C2=A0 }
=C2=A0 =C2=A0 = =C2=A0 catch (ForcedUnwind const&)
=C2=A0 =C2=A0 =C2=A0 { throw; }
=C2=A0 =C2=A0= =C2=A0 catch (...)
=C2=A0 =C2=A0 =C2=A0 {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 except = =3D std::current_exception();=C2=A0 =C2=A0 =C2=A0 =C2=A0 return { recovery, nullptr };
= =C2=A0 =C2=A0 =C2=A0 }
= =C2=A0 =C2=A0 }

no matter what the code will not work - you have no guarantee that 'recovery' is still valid in the catch clause
=
as I explained the stack 'recovery= 9; is pointing to might be invalidated during execution of 'f'
<= /span>

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--94eb2c1989ee15c5880549aac68b-- .