From 2345020075240057169 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,7c21e57f4a25e5f3 X-Google-Attributes: gidf78e5,public X-Google-ArrivalTime: 2001-05-25 16:23:01 PST Path: archiver1.google.com!newsfeed.google.com!newsfeed.stanford.edu!skynet.be!dispose.news.demon.net!news.demon.co.uk!demon!mail2news.demon.co.uk!not-for-mail From: "James Kuyper Jr." Newsgroups: comp.std.c++ Subject: Re: deleted pointers in a container Date: Fri, 25 May 2001 23:21:37 GMT Organization: Not Enough Approved: Fergus Henderson , moderator of comp.std.c++ Message-ID: <3B0EE48C.C6000E3D@wizard.net> References: <3AF0BE2C.F07A2FB7@acm.org> <3AF69057.1778277E@acm.org> <873f7ae8.0105250552.71767b39@posting.google.com> X-Trace: mail2news.demon.co.uk 990832935 mail2news:4467 mail2news mail2news.demon.co.uk X-Complaints-To: abuse@demon.net X-Mail2News-Path: news.demon.net!mulga.cs.mu.oz.au X-Authentication-Warning: mulga.cs.mu.OZ.AU: fjh set sender to devnull@stump.algebra.com using -f X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) X-Accept-Language: en,es,de,ru MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 41 Xref: archiver1.google.com comp.std.c++:5301 Kiril Avdeiv wrote: > > James Dennett wrote in message news:<3AF69057.1778277E@acm.org>... > > Assaf Lavie wrote: > > > > > > >IIRC that's not specified by the Standard. Maybe it should > > > >be, or maybe it is and I've just missed it. > > > > > > Why do you make the assertion that copying deallocated pointers (not > > > de-referencing them) yields undefined behavior if it is not specified by the > > > standard? > > > > The fact that copying deallocated pointers yields undefined > > behaviour *is* clearly stated by the Standard. > > James, I am very grateful if you show where it is stated. 3.6.3.2 says: "... the deallocation function shall deallocate the storage referenced by the pointer, rendering invalid all pointers referring to any part of the _deallocated storage_. The effect of using an invalid pointer value (including passing it to a deallocation function) is undefined." Therefore, if you copy a deallocated pointer in any way that uses the value, such as: p = q; then the copy allows undefined behavior. If you copy it in a manner that doesn't use the value, such as memcpy(&p, &q, sizeof(p)); then it's perfectly safe. --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.research.att.com/~austern/csc/faq.html ]