From 7369104274472981303 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,8466591b9cd11017 X-Google-Attributes: gidf78e5,public From: comeau@panix.com (Greg Comeau) Subject: Re: C++ 'philosophy' question, Constructors/Destructors Date: 2000/06/17 Message-ID: <8ie1dm$qtj$1@panix6.panix.com>#1/1 X-Deja-AN: 635478618 Approved: Fergus Henderson , moderator of comp.std.c++ References: <394a5536.29331042@news.columbia.edu> X-Authentication-Warning: mulga.cs.mu.OZ.AU: fjh set sender to devnull@stump.algebra.com using -f X-Complaints-To: abuse@demon.net X-Mail2News-Path: news.demon.net!mulga.cs.mu.oz.au X-Trace: mail2news.demon.co.uk 961187090 mail2news:27913 mail2news mail2news.demon.co.uk Organization: Comeau Computing; http://www.comeaucomputing.com X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) Reply-To: comeau@comeaucomputing.com Newsgroups: comp.std.c++ In article , Hyman Rosen wrote: >lp178@columbia.edu (Leonid Portnoy) writes: >> This raises another question : Why does a class have only one >> destructor, but multiple constructors? > >Because objects are created by intention, with expressions that >supply arguments that can be used to select a constructor. They >are destroyed without any such information, such as by going out >of scope, so there is only one destructor. You are perfectly free >to write multiple overloaded "destroy" functions and call them >yourself as needed. I'm not clear this is what you just said, but it's worth pointing out that destruction is not quite the reverse of construction, despite so many people being told it is. That is to say, yes, while ctors turn raw memory into something useful and dtors turn those useful thing back ("reverse") to raw memory, what's also important to note is that you need to consider the life of the object. Once the object is "alive", what happened at construction time may or may not be important anymore, therefore, have a matching dtor may or may not be important anymore. This sort of begs that if it has multiple ctors then it should be a requirement that there be multiple versions of every member function, not just dtors.... which does not necessarily follow... clearly it may in certain cases, but apparently they were not deemed common/significant enough, and when they are, you do somethign such as what Hyman suggests. - Greg -- Comeau Computing, Producers of Comeau C/C++ 4.2.42 (4.2.43 BETA starting) Try Comeau C++ online at http://www.comeaucomputing.com/tryitout Email: comeau@comeaucomputing.com / WEB: http://www.comeaucomputing.com --- [ 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://reality.sgi.com/austern_mti/std-c++/faq.html ]