From 9162281108462089644 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,8017beb93f8fbefc X-Google-Attributes: gidf78e5,public X-Google-ArrivalTime: 2001-06-12 14:07:01 PST Path: archiver1.google.com!newsfeed.google.com!newsfeed.stanford.edu!newsfeed.gamma.ru!Gamma.RU!newsfeed.icl.net!dispose.news.demon.net!news.demon.co.uk!demon!mail2news.demon.co.uk!not-for-mail From: "Igor A. Goussarov" Newsgroups: comp.std.c++ Subject: Re: Incomplete types Date: Tue, 12 Jun 2001 21:06:32 GMT Organization: Akella Approved: Fergus Henderson , moderator of comp.std.c++ Message-ID: <3B26648E.39F5202@akella.com> References: <3B250752.99C15516@akella.com> <3B253155.D66B49E5@spamcop.net> X-Trace: mail2news.demon.co.uk 992379998 mail2news:13152 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: ru,en MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 42 Xref: archiver1.google.com comp.std.c++:5990 Ron Natalie wrote: > > "Igor A. Goussarov" wrote: > > > > > Sorry, I didn't make myself clear enough. Deleting something is a > > two-step process. First, an object is destroyed. Second, the memory > > allocated for that object is freed. Destroying a builtin type is a > > no-op. Thus deleting an int, char, double, pointer or any other 'simple' > > type is effectively the same as freeing up the memory. That's why I said > > that deleting something via void* can be tolerated, but an explicit cast > > to void* should be required as a sign that a programmer knows what he is > > doing. > > You've lost me. Why does a cast to void* indicate that the programmer > knows what he is doing. If he knew what he was doing, the pointer would > be properly declared. These 'simple types' are always complete anyhow. Let's start again. The current Standard doesn't forbid a deletion of an incomplete type. Such action is currently described as 'undefined behaviour'. This seems to be plain wrong because this is a very likely error. So (IMO) it should be made a compile-time error. So let's imagine it is made an error. But since the deletion of an incomplete type was allowed up to now, there should be a way (kinda 'backward compatibility') of doing such deletion asif it is still allowed (however I can't imagine a program that rely on this deletion with undefined behaviour, so maybe this is not that necessary). And what I was proposing is: 1) Make the deletion of an incomplete type an error. 2) Leave some way to do this obscure deletion 'old style'. One of the possible ways of achieving 2) is allowing this obscure deletion via explicit cast to void*. If you think that 2) should not be allowed at all then well, I can understand you. Igor --- [ 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 ]