220 35109 <172fc6328e80a64a748e4fabe78cfa5f@kdab.com> article Path: news.gmane.org!.POSTED!not-for-mail From: Marc Mutz Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Marking more std::string_view members noexcept Date: Thu, 26 Oct 2017 10:40:50 +0200 Organization: KDAB Lines: 40 Approved: news@gmane.org Message-ID: <172fc6328e80a64a748e4fabe78cfa5f@kdab.com> References: <3d03cd7d-2177-98fd-408d-f74b1f6a8552@gmail.com> <2b8591ee-3a1e-4a41-8c14-221bdc5cd1e4@isocpp.org> <0574ad73-0d36-47c0-9e47-79e234cc6708@isocpp.org> <79ff7517-9d44-4770-8124-a2a036a2e6be@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"; format=flowed X-Trace: blaine.gmane.org 1509007272 19671 195.159.176.226 (26 Oct 2017 08:41:12 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 26 Oct 2017 08:41:12 +0000 (UTC) Cc: pavel.kryukov@phystech.edu To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCRPXDOU7ECRBG57Y3HQKGQEGLFXNHA@isocpp.org Thu Oct 26 10:41:03 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-wr0-f200.google.com ([209.85.128.200]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1e7dif-00034Q-J7 for gclcip-std-proposals@m.gmane.org; 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[176.9.126.58]) by mx.google.com with ESMTPS id 38si3331789wry.273.2017.10.26.01.40.59 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 26 Oct 2017 01:40:59 -0700 (PDT) Received-SPF: pass (google.com: domain of marc.mutz@kdab.com designates 176.9.126.58 as permitted sender) client-ip=176.9.126.58; X-Virus-Scanned: amavisd-new at kdab.com Original-Sender: marc@kdab.com In-Reply-To: <79ff7517-9d44-4770-8124-a2a036a2e6be@isocpp.org> X-Sender: marc.mutz@kdab.com X-Original-Sender: marc.mutz@kdab.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of marc.mutz@kdab.com designates 176.9.126.58 as permitted sender) smtp.mailfrom=marc.mutz@kdab.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:35109 Archived-At: On 2017-10-25 22:07, pavel.kryukov@phystech.edu wrote: > Hi > > If there was a ctor from array reference, would it be noexcept? > > template > constexpr basic_string_view(const charT(&str)[N]) noexcept; This one still has the precondition that [Char, N) is a valid range. It might not be: char bug[512]; auto s = string_view(bug); but you can't check (in C++) for that. FWIW, QStringView's Char[N] and Char* ctors are noexcept while the (Char*, n) and (Char*, Char*) ones are not. I believe I did it like that according to (non-/)checkability of preconditions (you can't check for precondition violations for the first two, but you can check for some violations for the other two). If you can't check using C++, then you can't add an assert[1]. > Of course, you may do reinterpret_cast and pass something wrong to it, > but it would be programmer's responsibility. Meeting the preconditions of a function he's calling is _always_ the programmer's responsibility. Thanks, Marc [1] not entirely true: https://codereview.qt-project.org/193707 -- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. 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