220 19711 <2301060.qH0H7yDpJ1@tjmaciei-mobl4> article Path: news.gmane.org!not-for-mail From: Thiago Macieira Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: rtti: missing sizeof() and alignof() in std::type_info Date: Thu, 06 Aug 2015 16:43:31 -0700 Lines: 34 Approved: news@gmane.org Message-ID: <2301060.qH0H7yDpJ1@tjmaciei-mobl4> References: <3718ba80-d410-4cca-8e15-5113450281cc@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: ger.gmane.org 1438904637 29276 80.91.229.3 (6 Aug 2015 23:43:57 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 6 Aug 2015 23:43:57 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCB4TK757YBRBJ7CR6XAKGQERDOIFCQ@isocpp.org Fri Aug 07 01:43:37 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-la0-f70.google.com ([209.85.215.70]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZNUoz-0007Kl-4w for gclcip-std-proposals@m.gmane.org; Fri, 07 Aug 2015 01:43:37 +0200 Original-Received: by labth1 with SMTP id th1sf33292135lab.2 for ; Thu, 06 Aug 2015 16:43:36 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:subject:date:message-id:user-agent :in-reply-to:references:mime-version:content-type: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=aSBnm+WxtmblK0Q7BTVvMfJ2+jRZBLeYo+okosfkoXI=; b=aqrUFGe0pJbH3InmALUb8aQBBOb/h10tDgSc1QiyWvkZM7wMXObrTnIPkcoBXvNwi1 HqBVX/ntblgT3qrQXLnhf5U+clKsqIUMLN50jQ8Xz0AngFsnE3wxPL314qRgRlsInMsg 4myFB04uM+OAyajyF69Yk4JdIT5LqX9t+iOA1Sunaqgd9jPTvSRrDw85xYN/5Nyf7Ff3 dTUnPy/y+7CW4h/PwpAH6TFRdM7wrfwFpW40jLROsrZimW87ci3A7dm8s0AbOvaDuPYK auNbZwYCaorVfdNxlfHFa4T9YbaAGrKhpc17U2ZVSw9r9xjLPXxNhgNSGOmpCMPoKJhm DQTg= X-Gm-Message-State: ALoCoQmgnG0gBB0SyIPfOa7RohREwwH+g72VwSIzYX+xuMZSY5KAJPXR2fS2pTEoSn+NeYsQ0HBG X-Received: by 10.152.182.226 with SMTP id eh2mr1235348lac.0.1438904616398; Thu, 06 Aug 2015 16:43:36 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.180.106.100 with SMTP id gt4ls231242wib.6.canary; Thu, 06 Aug 2015 16:43:35 -0700 (PDT) X-Received: by 10.180.74.52 with SMTP id q20mr147556wiv.94.1438904615030; Thu, 06 Aug 2015 16:43:35 -0700 (PDT) Original-Received: from gondolin.macieira.info (gondolin.macieira.info. [78.47.120.188]) by mx.google.com with ESMTP id g7si16019206wjy.213.2015.08.06.16.43.34 for ; Thu, 06 Aug 2015 16:43:34 -0700 (PDT) Received-SPF: pass (google.com: domain of thiago@macieira.org designates 78.47.120.188 as permitted sender) client-ip=78.47.120.188; Original-Received: from tjmaciei-mobl4.localnet (unknown [134.134.139.76]) by gondolin.macieira.info (Postfix) with ESMTPSA id B2E5D11BA03 for ; Thu, 6 Aug 2015 16:43:33 -0700 (PDT) User-Agent: KMail/4.14.9 (Linux/4.1.3-1-desktop; KDE/4.14.9; x86_64; ; ) In-Reply-To: <3718ba80-d410-4cca-8e15-5113450281cc@isocpp.org> X-Original-Sender: thiago@macieira.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of thiago@macieira.org designates 78.47.120.188 as permitted sender) smtp.mail=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:19711 Archived-At: On Thursday 06 August 2015 13:42:57 Matthew Fioravante wrote: > Is there any reason that sizeof(T) and alignof(T) are not available via the > type_info struct from typeid()? > > I want to use the address and size in particular to create a mapping of > objects within other objects for debugging purposes. It doesn't actually > appear to be possible in C++14 to get the size of the most dynamic type > without rolling your own rtti solution. > > What I would suggest is adding size() and align() methods to type_info to > return sizeof(T) and alignof(T) respectively. Sounds like a reasonable proposal, but one tricky to implement. In order to support polymorphic types linked before this feature, it needs to support returning sizeOf() == alignOf() == 0 or another sentinel value that indicates absence of information. Also note that typeid(void) is valid, so what does typeid(void).sizeOf() return? -- Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org Software Architect - Intel Open Source Technology Center PGP/GPG: 0x6EF45358; fingerprint: E067 918B B660 DBD1 105C 966C 33F5 F005 6EF4 5358 -- --- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. 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