From 231538048130044141 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,991a11e8ea03ee36 X-Google-Attributes: gidf78e5,public From: Valentin Bonnard Subject: Re: Overload resolution and references Date: 1999/03/24 Message-ID: <36F919B0.6572@wanadoo.fr>#1/1 X-Deja-AN: 458568870 X-NNTP-Posting-Host: jonque.ens.fr Content-Transfer-Encoding: 7bit Approved: stephen.clamage@sun.com (comp.std.c++) References: <36F7E144.23FA@smarts.com> To: Jerry Leichter X-UID: 0000000001 X-Status: $$$T Content-Type: text/plain; charset=us-ascii Organization: Ecole Normale Superieure, Paris, France Mime-Version: 1.0 Newsgroups: comp.std.c++ Originator: clamage@taumet Jerry Leichter wrote: > HP's aCC (missing the absolute latest set of patches, but I don't recall > seeing any indication of a patch in this area) compiles the whole thing > with no complaints. The result produces the following output: First let write down the viable functions: > 26: u(i)-> u(int&) Candidates are: u(int&), u(const int&) But u(const int&) requires a qualification conversion (at least I think it's called qualification conversion), so this ok. > 27: u(ci)-> u(const int&) Candidates are: u(const int&) ok > 28: u(1)-> u(const int&) Candidates are: u(const int&) ok > 32: v(i)-> v(const int&) > 33: v(ci)-> v(const int&) > 34: v(1)-> v(int) For the above cases: Candidates are: v(int), v(const int&) They aren't comparable, so these calls are ambiguous. > Lines 32 and 33 make sense if you assume a preference, in overloading, > for a const ref T over a T. This is a reasonable thing to do - I disagree. > certainly for class types - but I can't seem to find language to justify > it. Line 34, on the other hand, is a puzzle: How does it differ from > line 33? 1 is an rvalue of type int, ci is a lvalue of type const int (Note that g++ makes all these three cases ambiguous. :-) > Can anyone explicate? The rules were badly broken and changed recently. -- Valentin Bonnard [ 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 ]