From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 66585 invoked by alias); 18 Jul 2017 15:38:39 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 66450 invoked by uid 89); 18 Jul 2017 15:38:38 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=Hx-languages-length:1615 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Tue, 18 Jul 2017 15:38:37 +0000 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D671D7EBDB; Tue, 18 Jul 2017 15:38:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com D671D7EBDB Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=palves@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com D671D7EBDB Received: from [127.0.0.1] (ovpn04.gateway.prod.ext.ams2.redhat.com [10.39.146.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2C28A7F7E1; Tue, 18 Jul 2017 15:38:34 +0000 (UTC) Subject: Re: [PATCH] Add DISABLE_COPY_AND_ASSIGN To: Yao Qi References: <1500385686-19857-1-git-send-email-yao.qi@linaro.org> <179e2d35-d903-1d6d-256a-063a35d677d2@redhat.com> <86iniprd5l.fsf@gmail.com> Cc: gdb-patches@sourceware.org From: Pedro Alves Message-ID: <075e7089-199f-f251-c4a2-58099b5f06e9@redhat.com> Date: Tue, 18 Jul 2017 15:38:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <86iniprd5l.fsf@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SW-Source: 2017-07/txt/msg00258.txt.bz2 On 07/18/2017 04:13 PM, Yao Qi wrote: > Pedro Alves writes: > >> Yes, please. I've been meaning to add something like this for a while. >> >> IMO, this could go in include/ansidecl.h, with a fallback version for >> #if __cplusplus < C++11 that declares the methods without =delete (you >> get a link error instead). >> > > I thought about adding this into include/, but can't find the right > file. I'll move the macro to include/ansidecl.h. Thanks. Note that that file is maintained by gcc. > >>> /* Pull in gdb::unique_xmalloc_ptr. */ >>> #include "common/gdb_unique_ptr.h" >>> >>> +#define DISABLE_COPY_AND_ASSIGN(TYPE) \ >>> + TYPE (const TYPE&) = delete; \ >>> + void operator= (const TYPE &) = delete; >>> + >> >> Should this have an intro comment? >> > > I thought it is too simple to have a comment :) How about this? > > /* A macro to disable the copy constructor and assignment operator. > When building with C++ 11, explicitly delete these methods. > Otherwise, place this macro in the private: declarations of a class. */ How about this tweak: /* A macro to disable the copy constructor and assignment operator. When building with C++11 and above, the methods are explicitly deleted, causing a compile-time error if something tries to copy. For C++03, this just declares the methods, causing a link-time error if the methods end up called (assuming you don't define them). For C++03, for best results, place the macro under the private: access specifier, so that most attempts at copy are caught at compile-time. */ Thanks, Pedro Alves