From 8727415790302054259 X-Google-Language: ENGLISH,ASCII X-Google-Thread: f78e5,b43d17d27e7171b0 X-Google-Attributes: gidf78e5,public X-Google-ArrivalTime: 2000-12-13 07:55:05 PST Path: supernews.google.com!sn-xit-02!supernews.com!router1.news.adelphia.net!cyclone.news.idirect.com.MISMATCH!newsfeed.direct.ca!look.ca!newsfeed.icl.net!colt.net!dispose.news.demon.net!demon!news.demon.co.uk!demon!mail2news.demon.co.uk!not-for-mail From: Daniel Frey Newsgroups: comp.std.c++ Subject: Re: explicit operator T() Date: Wed, 13 Dec 2000 15:54:43 GMT Organization: aixigo AG Approved: Fergus Henderson , moderator of comp.std.c++ Message-ID: <3A3791B1.E2875EEC@aixigo.de> References: <3A2D10EE.35544D0A@aixigo.de> <3A2E0413.96D42EFD@aixigo.de> <3A2F5BF8.B8CFDBED@physik.tu-muenchen.de> X-Trace: mail2news.demon.co.uk 976722890 mail2news:4485 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) Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 X-Sender: 320060065507-0001@t-dialin.net X-Accept-Language: en X-MIME-Autoconverted: from quoted-printable to 8bit by mulga.cs.mu.OZ.AU id CAA02088 Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by mulga.cs.mu.OZ.AU id CAA04084 Lines: 42 Xref: supernews.google.com comp.std.c++:2949 Gene Bushuyev wrote: >=20 > This opens a floodgate of problems. How do you decide what conversions > "explicit" should prevent? How about promotions? How about identity > conversions? Will derived-to-base class conversion be allowed? If you s= ay > any conversion is disallowed with "explicit" then it's usefulness is ne= xt to > nil. IMHO 'explicit' for parameters should work like this: void func( explicit T arg ) { // ... } void funcB( explicit const T& arg ) { // ... } should be equivilent to void func( T& arg_ ) { T arg( arg_ ); // ... } void funcB( T& arg_ ) { const T& arg( arg_ ); // ... } where 'arg_' should be invisible inside the functions bodies '// ...'. This should yield no surprises and shows that the compiler doesn't need any new magic for 'explicit' here. It just hides a temporary (or creates an unnamed temporary depending on your point of view) that can be optimized away. Regards, Daniel ---------------------------------------------- aixigo AG - Financial Research and Education Schlo=DF-Rahe-Stra=DFe 15, 52072 Aachen, Germany Tel: +49 (0)241 936737-42 Fax: -99 Daniel.Frey@aixigo.de http://www.aixigo.de -------------------- "wir machen Anleger" ---- --- [ 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 ] [ Note that the FAQ URL has changed! Please update your bookmarks. ]