220 9290 article Path: news.gmane.org!not-for-mail From: Matthew Woehlke Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Precise Per-Type Cyclic Garbage Collection (DRAFT 1) Date: Tue, 11 Feb 2014 14:54:42 -0500 Lines: 43 Approved: news@gmane.org Message-ID: References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed X-Trace: ger.gmane.org 1392148495 11962 80.91.229.3 (11 Feb 2014 19:54:55 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 11 Feb 2014 19:54:55 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCO5FYHBU4ERBFMA5KLQKGQEO65VCQQ@isocpp.org Tue Feb 11 20:55:04 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-fa0-f70.google.com ([209.85.161.70]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1WDJQ7-0007FE-0j for gclcip-std-proposals@m.gmane.org; Tue, 11 Feb 2014 20:55:03 +0100 Original-Received: by mail-fa0-f70.google.com with SMTP id x10sf14868322fax.5 for ; Tue, 11 Feb 2014 11:55:02 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:to:from:subject:date:lines:message-id:references :mime-version:user-agent:in-reply-to:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe:content-type; bh=a2eTyKQA4yC4x9PUA6R2FCKSne2K/hxClyUnwhjhMSI=; b=S5WP16LKpAqNx7mV43/XlW3Bkd7yFu7rdlsgQHDzfhJq/8cJPFFcIR7j7H2FFnMas4 EiLP+5+91sAstkorQASLqKBqCfqWXt/kMg62uEDzm5ysVVjpSzn0JjoW8xURPaA+JdsU 3GWtckoZUv9hBbQX25DMra/134xtQG+4fywj4r4dbaW9dKnATjSH9QHvTTAns0kmS2y5 i2mQXVKowiy2OkvVr6nDMERlwAhBnSyT7LhP8X8Xzc0vOvbKZpBYNpWBWKshWsiUFxnR +Ei4hc+KYVy/9BRY2cKKm+9jTUEF8iJZNL92Xr1dLxrsVpeMQxsHbwSDQkn1bwMQzzYn 5iOg== X-Gm-Message-State: ALoCoQk//yxat4t/e2RuwYIkYBcdrOZIKurAE8xiky4yXjnbCqIewiYftThD3LxtRns6EfTjeYC+ X-Received: by 10.112.215.3 with SMTP id oe3mr288946lbc.20.1392148502437; Tue, 11 Feb 2014 11:55:02 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.152.45.66 with SMTP id k2ls390593lam.11.gmail; Tue, 11 Feb 2014 11:55:01 -0800 (PST) X-Received: by 10.112.166.68 with SMTP id ze4mr2517585lbb.58.1392148501186; Tue, 11 Feb 2014 11:55:01 -0800 (PST) Original-Received: from plane.gmane.org (plane.gmane.org. [80.91.229.3]) by mx.google.com with ESMTPS id l9si10817989lbd.179.2014.02.11.11.55.00 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 11 Feb 2014 11:55:00 -0800 (PST) Received-SPF: pass (google.com: domain of gclcip-std-proposals@m.gmane.org designates 80.91.229.3 as permitted sender) client-ip=80.91.229.3; Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1WDJPy-0007AY-Lb for std-proposals@isocpp.org; Tue, 11 Feb 2014 20:54:54 +0100 Original-Received: from tripoint.kitware.com ([66.194.253.20]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 11 Feb 2014 20:54:54 +0100 Original-Received: from mw_triad by tripoint.kitware.com with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 11 Feb 2014 20:54:54 +0100 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 34 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: tripoint.kitware.com User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 In-Reply-To: X-Original-Sender: mw_triad@users.sourceforge.net X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of gclcip-std-proposals@m.gmane.org designates 80.91.229.3 as permitted sender) smtp.mail=gclcip-std-proposals@m.gmane.org 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:9290 Archived-At: On 2014-02-11 14:13, xavi wrote: > My main concern is whether a language extension is really necessary or it > could be implemented as a library. I believe there are already libraries in the wild that do this. IIRC, VTK (http://vtk.org) is one... See also http://www.aosabook.org/en/vtk.html and http://www.vtk.org/doc/release/5.10/html/classvtkGarbageCollector.html. > There might be certain things missing in the language: > - Being able to forbid automatic storage for certain types. > - Having some mechanism so that objects can only be created inside a > smart pointer. Without inheritance, it's easy, by making the constructors > private and make_ptr (or something similar) a friend. These days you probably just want to friend std::make_shared. > With inheritance things get much more complicated, so the language > might need to be changed there. I'm not sure a technical solution to this problem is required. If someone wants to shoot themselves in the foot by bypassing a base class that is intended to only ever be constructed into a shared_ptr... > - Maybe tweak virtual inheritance so that it's possible to inherit from > two ref-counted classes without significant overhead. Is this a problem in cases other than non-virtual inheritance from an intrusive pointer class? (Do I miss why this would be an issue with plain old std::shared_ptr?) -- Matthew -- --- 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. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposals/. .