From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Thread: 103376,ee82e0a06c8bbead X-Google-NewGroupId: yes X-Google-Attributes: gida07f3367d7,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Received: by 10.68.74.201 with SMTP id w9mr8359397pbv.0.1334007545531; Mon, 09 Apr 2012 14:39:05 -0700 (PDT) Path: r9ni37911pbh.0!nntp.google.com!news1.google.com!newsfeed2.dallas1.level3.net!news.level3.com!bloom-beacon.mit.edu!newsswitch.lcs.mit.edu!nntp.TheWorld.com!.POSTED!not-for-mail From: Robert A Duff Newsgroups: comp.lang.ada Subject: Re: A Gnother Gnasty bug Date: Mon, 09 Apr 2012 17:39:04 -0400 Organization: The World Public Access UNIX, Brookline, MA Message-ID: References: <22193583.1528.1333759470339.JavaMail.geo-discussion-forums@vbdn7> <87mx6nvlwo.fsf@ludovic-brenta.org> <16824531.853.1334005741021.JavaMail.geo-discussion-forums@ynbv36> NNTP-Posting-Host: shell01.theworld.com Mime-Version: 1.0 X-Trace: pcls6.std.com 1334007545 6397 192.74.137.71 (9 Apr 2012 21:39:05 GMT) X-Complaints-To: abuse@TheWorld.com NNTP-Posting-Date: Mon, 9 Apr 2012 21:39:05 +0000 (UTC) User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/21.3 (irix) Cancel-Lock: sha1:eq3xzVpPCfqPA42KHUUkf62yP1A= Content-Type: text/plain; charset=us-ascii Date: 2012-04-09T17:39:04-04:00 List-Id: Adam Beneschan writes: > That last isn't really true, I think. Yes, you're right. An implementation can copy limited objects any time it likes, so long as it makes the copy semantically invisible (which, as you say, would involve fixing up all the pointers). An implementation that does copying garbage collection would do that. But otherwise, it isn't really practical. Think about copying locks (as in protected objects). If a copy isn't semantically visible, then is it a copy? ;-) - Bob