From -5106815708854372396 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,11af4794c44339e8 X-Google-Attributes: gidf78e5,public From: jpotter@falcon.lhup.edu (John Potter) Subject: Re: Can you static_cast between enums? Date: 1999/12/20 Message-ID: <385c3972.111450192@news.csrlink.net>#1/1 X-Deja-AN: 563001766 Approved: Fergus Henderson References: <832fub$t0$1@news.hamburg.pop.de> <385AA7AA.8D983B3@tribble.com> <83gnm6$u1f$1@nnrp1.deja.com> X-Original-Date: 18 Dec 1999 19:49:01 -0600 X-Complaints-To: news@news.unimelb.edu.au X-Trace: ariel.ucs.unimelb.edu.au 945700268 5094 128.250.37.153 (20 Dec 1999 14:31:08 GMT) Organization: Newscene Public Access Usenet News Service (http://www.newscene.com/) X-Auth: PGPMoose V1.1 PGP comp.std.c++ iQBFAgUAOF49yeEDnX0m9pzZAQHq2QF/R3tM2pvw8Wc/QlCqPF2MyGXiwKS4j1Gs h7j8YD8T4Sv0IHn9BPrCi3p+mgr0/Toy =Mryw NNTP-Posting-Date: 20 Dec 1999 14:31:08 GMT Newsgroups: comp.std.c++ On 18 Dec 1999 23:24:34 GMT, wmm@fastdial.net wrote: : : In article <385AA7AA.8D983B3@tribble.com>, : David R Tribble wrote: : > So what does the following expression do, in terms of the xxx_cast : > operators? : > : > enum Color { RED, WHITE, BLUE }; : > enum Hue { R, W, B }; : > : > Hue h = (Hue)RED; // not static_cast(RED)? : : None of the casting mechanisms -- "(Hue)RED", "Hue(RED)", and : "static_cast(RED)" -- allows this conversion, according to : the current wording of the standard. As I said earlier in this : thread, this is an oversight and is expected to be corrected in : the first Technical Corrigendum. Hue h(static_cast(static_cast(RED))); is a bit messy. Is the following also an oversight? struct S { int x, y }; S s; int* p(static_cast(static_cast(&S))); We are assured that the address of the struct may be cast to the address of the first element; however, it must either be an implementation defined reinterpret_cast or a double cast with no assurances that it will work. 5.2.9/10 does not say "except that" like 5.2.10/*, but seems to make it questionable. John --- [ 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 ]