From 7931274501700764430 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,a5e7fc89a8659411 X-Google-Attributes: gidf78e5,public X-Google-ArrivalTime: 2003-07-21 11:33:57 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!logbridge.uoregon.edu!kibo.news.demon.net!mutlu.news.demon.net!demon!mail2news.demon.co.uk!devnull From: do-not-spam-benh@bwsint.com (Ben Hutchings) Newsgroups: comp.std.c++ Subject: Re: Voided application of indirection operator to pointer-to-void Date: Mon, 21 Jul 2003 18:33:57 +0000 (UTC) Lines: 37 Approved: fjh@cs.mu.oz.au (Fergus Henderson , moderator of comp.std.c++) Message-ID: References: <5765b025.0307210232.6c571eff@posting.google.com> X-Trace: mail2news.demon.co.uk 1058812437 12915 10.0.0.1 (21 Jul 2003 18:33:57 GMT) X-Complaints-To: abuse@demon.net NNTP-Posting-Date: Mon, 21 Jul 2003 18:33:57 +0000 (UTC) X-Received: from mulga.cs.mu.oz.au ([128.250.1.22]) by news.demon.co.uk with esmtp (Exim 4.12) id 19efTv-0003MA-00 for mail2news@news.news.demon.net; Mon, 21 Jul 2003 18:33:56 +0000 X-Received: from localhost (localhost [[UNIX: localhost]]) by mulga.cs.mu.OZ.AU id EAA02249; Tue, 22 Jul 2003 04:33:53 +1000 (EST) X-Authentication-Warning: mulga.cs.mu.OZ.AU: fjh set sender to devnull@stump.algebra.com using -f X-Path: comp-std-cpp-robomod!not-for-mail X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) X-Delivered-To: std-c++@ucar.edu X-Newsgroups: comp.std.c++ X-Reply-To: Ben Hutchings X-Orig-NNTP-Posting-Host: gold.businesswebsoftware.com (195.74.108.82) X-Orig-X-Trace: news.uni-berlin.de 1058805733 15477815 195.74.108.82 (16 [70929]) X-User-Agent: slrn/0.9.7.4 (Win32) X-Spam-Status: No, hits=-4.1 required=5.0 tests=AWL,BAYES_01,EMAIL_ATTRIBUTION,QUOTED_EMAIL_TEXT, REFERENCES,REPLY_WITH_QUOTES,USER_AGENT version=2.55 X-Spam-Checker-Version: SpamAssassin 2.55 (1.174.2.19-2003-05-19-exp) Xref: archiver1.google.com comp.std.c++:20254 In article <5765b025.0307210232.6c571eff@posting.google.com>, Al Grant wrote: > Is this legal C++? > > void f(void *pv) { *pv; } > > Comeau and g++ both fault it. 5.3.1 says the operand of * must be T* > where T is an object type or function type - so not void. > However, we have another source claiming the code is legal, citing 4.1 > as showing an intention to allow (undereferenced) lvalues of incomplete > type and deducing that if 5.3.1 forbids this it is an oversight. > > It seems to me that 4.1 only implies that lvalues of some incomplete > types may exist, You are quite right. There are no lvalues of void type (3.10p2). > and 5.3.1 indicates that those generated by the indirection operator > must have an object type. Or function type. > I can believe that the committee might have intended to allow creation > of void lvalues, motivated either by orthogonality, or by compatibility > with C. I very much doubt it; I can't see that it would be meaningful to have a void lvalue, and I don't believe C allows it either. (void rvalues do exist in both C and C++, though.) --- [ 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.jamesd.demon.co.uk/csc/faq.html ]