Article View: comp.std.c++
Article #3954Re: dynamic_cast<void*>
From: Fergus Henderson
Date: Mon, 08 Apr 1996 09:03
Date: Mon, 08 Apr 1996 09:03
37 lines
2420 bytes
2420 bytes
anhaeupl@late.e-technik.uni-erlangen.de (Bernd Anhaeupl) writes: >Section 5.2.6 paragraph 7 of the April 95 WP states, that for >polymorphic types, the result of a dynamic_cast<void*>(v) "is a >pointer to the complete object (12.6.2) pointed to by v". Now >section 12.6.2 does not define the term "complete object", which >actually happens in section 1.4 paragraph 2, but the term >"most derived class". This makes a differnce, if we pass a pointer >to a data member subobject (and not a base class subobject) to >dynamic_cast. According to 12.6.2, we would get the address of that >data member, according to 1.4, the address of the containing >object of that data member. > >Please note, that the term "complete object (12.6.2)" is also used >in section 5.2.7, where the typeid expression is defined. Therefore >I suppose, that in 5.2.6 and 5.2.7 "most derived object" is meant >instead of "complete object" in both sections. Is this correct? Yes. The term "complete object" was used to mean two different things by different members of the C++ committee; one of those meanings is what is now called "most derived object". This error has been corrected in the Jan 96 draft, both in 5.2.6 and in 5.2.7. -- Fergus Henderson <fjh@cs.mu.oz.au> | "I have always known that the pursuit WWW: <http://www.cs.mu.oz.au/~fjh> | of excellence is a lethal habit" PGP: finger fjh@128.250.37.3 | -- the last words of T. S. Garp. --- [ 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 ] [ FAQ: http://reality.sgi.com/employees/austern_mti/std-c++/faq.html ] [ Policy: http://reality.sgi.com/employees/austern_mti/std-c++/policy.html ] [ Comments? mailto:std-c++-request@ncar.ucar.edu ]
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From: fjh@mundook.cs.mu.OZ.AU (Fergus Henderson) Message-ID: <4k8g95$jcq@mulga.cs.mu.OZ.AU> X-Original-Date: 7 Apr 1996 13:34:29 GMT Path: arc1-ca.pugleaf.net!in1.uu.net!bounce-back Date: 08 Apr 96 09:03:00 GMT Approved: fjh@cs.mu.oz.au Newsgroups: comp.std.c++ Subject: Re: dynamic_cast<void*> Organization: Comp Sci, University of Melbourne References: <4k1a4r$dim@rznews.rrze.uni-erlangen.de> X-Auth: PGPMoose V1.1 PGP comp.std.c++ iQBFAgUBMWjWS+EDnX0m9pzZAQFd/gF+K/Z7I2g+Z56Ea6w1+AnCKVp1vPtwy1Rw /EmbWLKtycINQKPcWubkimtWpFY4/lGQ =cNU/