220 33027 article Path: news.gmane.org!.POSTED!not-for-mail From: Ville Voutilainen Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: std::optional - support for sentinel values Date: Thu, 29 Jun 2017 15:04:32 +0300 Lines: 23 Approved: news@gmane.org Message-ID: References: <6e23864f-827a-4bdb-89de-a60d8f5be993@isocpp.org> <9f81f2b9-958c-4018-9f78-a6ac2e425899@isocpp.org> <730d0077-5a80-4dce-8250-19be62b1a23b@isocpp.org> <20170629111649.5132370.85419.32148@gmail.com> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" X-Trace: blaine.gmane.org 1498737879 14400 195.159.176.226 (29 Jun 2017 12:04:39 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 29 Jun 2017 12:04:39 +0000 (UTC) To: "ISO C++ Standard - Future Proposals" Original-X-From: std-proposals+bncBC5JHI7A7ALRBUOZ2PFAKGQE453TUZI@isocpp.org Thu Jun 29 14:04:30 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yw0-f200.google.com ([209.85.161.200]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dQYBR-0003G2-WA for gclcip-std-proposals@m.gmane.org; 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[2607:f8b0:4001:c0b::22d]) by mx.google.com with ESMTPS id d125si4626269iof.122.2017.06.29.05.04.33 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 29 Jun 2017 05:04:33 -0700 (PDT) Received-SPF: pass (google.com: domain of ville.voutilainen@gmail.com designates 2607:f8b0:4001:c0b::22d as permitted sender) client-ip=2607:f8b0:4001:c0b::22d; Original-Received: by mail-it0-x22d.google.com with SMTP id v202so44171160itb.0 for ; Thu, 29 Jun 2017 05:04:33 -0700 (PDT) X-Received: by 10.36.33.202 with SMTP id e193mr12744561ita.92.1498737873294; Thu, 29 Jun 2017 05:04:33 -0700 (PDT) Original-Received: by 10.36.122.211 with HTTP; Thu, 29 Jun 2017 05:04:32 -0700 (PDT) In-Reply-To: X-Original-Sender: ville.voutilainen@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.b=p1EImXPP; spf=pass (google.com: domain of ville.voutilainen@gmail.com designates 2607:f8b0:4001:c0b::22d as permitted sender) smtp.mailfrom=ville.voutilainen@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:33027 Archived-At: On 29 June 2017 at 14:50, Igor Baidiuk wrote: > If we introduce such "special wrapper", we'll lose in ergonomics, even if > this will save us from ABI breakage. > As for ABI, major compilers like MSVC or GCC do ABI breakage on major > version bump anyway. That's becoming less correct for msvc and is not at all correct for libstdc++. > Though I'd rather put that particular question aside for now. Let's imagine > we're up to a new type. The type is certainly useful, because it's more compact than std::optional is. I think it's worth having in the standard, but I can imagine some saying "too many types" without quantifying how many is too many and what the deciding factor is for that. :) -- 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/CAFk2RUYVCw7dbHThw-X4bRACiNQ6mim8jQWJFEu7U-C7zddgnQ%40mail.gmail.com. .