220 38130 <2300193.1RphyUdPvq@tjmaciei-mobl1> article Path: news.gmane.org!.POSTED!not-for-mail From: Thiago Macieira Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: memcpy/memset/etc overloads for volatile memory Date: Fri, 18 May 2018 17:16:39 -0700 Lines: 29 Approved: news@gmane.org Message-ID: <2300193.1RphyUdPvq@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 1526688882 5908 195.159.176.226 (19 May 2018 00:14:42 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 19 May 2018 00:14:42 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCB4TK757YBRB26Z7XLQKGQEOFKNMHY@isocpp.org Sat May 19 02:14:38 2018 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-qk0-f198.google.com ([209.85.220.198]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1fJpWA-0001M1-4p for gclcip-std-proposals@m.gmane.org; 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[209.222.10.136]) by mx.google.com with ESMTPS id p12-v6si3194584qvl.241.2018.05.18.17.16.42 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 18 May 2018 17:16:42 -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 [IPv6:2601:1c0:4501:5f9f:bc1f:402:4b5e:fda5]) by smtp.macieira.info (Postfix) with ESMTPSA id 85B13E7B4 for ; Fri, 18 May 2018 17:16:40 -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:38130 Archived-At: On Friday, 18 May 2018 14:13:15 PDT Andrey Semashev wrote: > What is "the right thing"? Does it have to be a byte-granular operation? > Does it have to be a forward iteration? Is this behavior the same on all > implementations? You have to answer on all these questions in the > standard wording so that everyone can rely on the exact memory access > pattern, which is important in case of volatile memory. > > If it is not important in your case then you don't need volatile and > hence the overload. On the other hand, if your memory storage requires a specific behaviour which cannot be standardised, maybe you should implement the copying directly in your code. It's not like bytewise memcpy and memset are particularly difficult to implement... It's the SIMD-optimised with cacheline-alignment and such that are. -- 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/2300193.1RphyUdPvq%40tjmaciei-mobl1. .