From 8800965000908838722 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,ccbfcafab96cf493 X-Google-Attributes: gidf78e5,public X-Google-ArrivalTime: 2001-12-06 10:43:01 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!dispose.news.demon.net!news.demon.co.uk!demon!mail2news.demon.co.uk!not-for-mail From: pdimov@mmltd.net (Peter Dimov) Newsgroups: comp.std.c++ Subject: Re: Proposol to increase robustness of programs Date: Thu, 6 Dec 2001 18:42:11 GMT Organization: http://groups.google.com/ Approved: Fergus Henderson , moderator of comp.std.c++ Message-ID: <7dc3b1ea.0112060840.69c166cc@posting.google.com> References: <3BFE97B3.91430FB1@wanadoo.fr> <3C058126.36357A00@acm.org> <3C06A0CE.E91638E8@acm.org> <3C0C1E25.1A0247AD@acm.org> <3C0D410B.7198B21D@wanadoo.fr> <3C0D4878.A86E882E@acm.org> X-Trace: mail2news.demon.co.uk 1007664136 mail2news:21163 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) Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit NNTP-Posting-Date: 6 Dec 2001 16:40:09 GMT Lines: 54 Xref: archiver1.google.com comp.std.c++:8517 Pete Becker wrote in message news:<3C0D4878.A86E882E@acm.org>... > Lo? Joly wrote: > > > > Pete Becker wrote: > > > > > > Jim Barry wrote: > > > > > > > > I don't agree that this is an issue that only affects novices. > > > > > > How often have you had a problem because you changed a virtual functi > on > > > to non-virtual? > > > > I am not sure you read my latest answear, so I repeat it : The proble i > s > > NOT changing a function from non virtual to virtual. The problem is > > making a modification to one parameter of the base virtual function, an > d > > not applying the same modification to the derived function. > > > > Fine. How often have you had a problem because you made a modification > to one parameter of the base virtual function, and didn't apply the same > modification to the derived function? After changing a base virtual function signature, the typical procedure is to locate all overriders - by hand - and fix them. Rarely does a programmer wait for the tests to fail. They will. No new information would be gained. With consistent use of 'override', the process is automated. There are ways in current C++ to achieve the same level of error checking (never override a non-pure virtual) but unfortunately they can't be applied universally. > Of course, the same sort of > problem can arise with overloading -- if you modify one parameter you > can change which version gets called by other code. Do you also have a > proposal for fixing that? A solution for this problem would likely have a different cost/benefit ratio. -- Peter Dimov Multi Media Ltd. --- [ 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 ]