220 37369 <1576846.pGoWqklWjJ@tjmaciei-mobl1> article Path: news.gmane.org!.POSTED!not-for-mail From: Thiago Macieira Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: `offsetof` in a macro-less, modular world Date: Fri, 16 Mar 2018 14:04:08 -0700 Lines: 23 Approved: news@gmane.org Message-ID: <1576846.pGoWqklWjJ@tjmaciei-mobl1> References: 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 1521234131 28578 195.159.176.226 (16 Mar 2018 21:02:11 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 16 Mar 2018 21:02:11 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCB4TK757YBRBTHCWDKQKGQEDMFJFDQ@isocpp.org Fri Mar 16 22:02:07 2018 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-qt0-f199.google.com ([209.85.216.199]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ewwUI-0007JZ-Ru for gclcip-std-proposals@m.gmane.org; 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[209.222.10.136]) by mx.google.com with ESMTPS id r13si5342106qtr.418.2018.03.16.14.04.12 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 16 Mar 2018 14:04:12 -0700 (PDT) Received-SPF: pass (google.com: domain of thiago@macieira.org designates 209.222.10.136 as permitted sender) client-ip=209.222.10.136; Original-Received: from tjmaciei-mobl1.localnet (unknown [134.134.139.76]) by smtp.macieira.info (Postfix) with ESMTPSA id 36AD5A774 for ; Fri, 16 Mar 2018 14:04:11 -0700 (PDT) In-Reply-To: X-Original-Sender: thiago@macieira.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of thiago@macieira.org designates 209.222.10.136 as permitted sender) smtp.mailfrom=thiago@macieira.org 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:37369 Archived-At: On Friday, 16 March 2018 11:56:29 PDT Myriachan wrote: > I really like Thiago's proposal regarding data member pointers, but it has > a major problem: it's an ABI break. Some proposed constructions would > allow data member pointers with a negative offset (pointing to the > containing class's members), and both the Microsoft and Itanium ABIs encode > null member pointers as -1. Not really. Negative offsets are already possible in some pathological pointer-to-members (don't ask me which ones). The ABI has to have a way to represent them in a way that is different from a null pointer. -- Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org Software Architect - Intel Open Source Technology Center -- 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/1576846.pGoWqklWjJ%40tjmaciei-mobl1. .