From -8055792737527360454 X-Google-Thread: f78e5,f6130266038a8c4d X-Google-Attributes: gidf78e5,public X-Google-Language: ENGLISH,ASCII Path: g2news1.google.com!news2.google.com!proxad.net!newsfeed.stueberl.de!feed.news.tiscali.de!easynet-monga!easynet.net!news.clara.net!wagner.news.clara.net!194.159.246.34.MISMATCH!peer-uk.news.demon.net!kibo.news.demon.net!news.demon.co.uk!demon!stump.algebra.com!devnull From: loic.actarus.joly@wanadoo.fr (=?ISO-8859-1?Q?Lo=EFc_Joly?=) Newsgroups: comp.std.c++ Subject: Re: Private Methodes declared outside of the class Date: Thu, 19 Aug 2004 15:49:23 GMT Organization: Wanadoo, l'internet avec France Telecom Lines: 56 Sender: mail2news@demon.net Approved: fjh@cs.mu.oz.au (Fergus Henderson , moderator of comp.std.c++) Message-ID: References: <2oblfaF8nds3U1@uni-berlin.de> NNTP-Posting-Host: news.news.demon.net Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable X-Trace: news.demon.co.uk 1092930568 43 158.152.254.254 (19 Aug 2004 15:49:28 GMT) X-Complaints-To: abuse@demon.net NNTP-Posting-Date: Thu, 19 Aug 2004 15:49:28 +0000 (UTC) X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) X-User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7) Gecko/20040616 X-MIME-Autoconverted: from 8bit to quoted-printable by mulga.cs.mu.OZ.AU id i7JFnNYZ004430 X-Spam-Checker-Version: SpamAssassin 2.64-mulga_r1 (2004-01-11) on mulga.cs.mu.OZ.AU X-Spam-Status: No, hits=-4.6 required=5.0 tests=AWL,BAYES_00 autolearn=ham version=2.64-mulga_r1 X-Accept-Language: en-us, en X-Path: comp-std-cpp-robomod!not-for-mail X-Received: (from fjh@localhost) by mulga.cs.mu.OZ.AU (8.12.10+Sun/8.12.9/Submit) id i7JFnNuo004421; Fri, 20 Aug 2004 01:49:23 +1000 (EST) X-NNTP-Posting-Date: 19 Aug 2004 10:29:59 GMT X-Spam-Level: X-Delivered-To: std-c++@ucar.edu X-Authentication-Warning: mulga.cs.mu.OZ.AU: fjh set sender to devnull@stump.algebra.com using -f X-Newsgroups: comp.std.c++ Xref: g2news1.google.com comp.std.c++:1855 Steve Clamage wrote: > Ben Strasser wrote: >=20 >> >> I was wondering why you can not declare private methods outside of the= =20 >> class declaration? >=20 >=20 > If you could declare member functions outside the class definition,=20 > anyone could hijack the class (for good or bad purposes), or break the=20 > class invariants without anyone knowing. Not if you can write only private non-virtual functions outside of the=20 class : Sure you could add functions to the class, but nobody except the=20 implementation of the class would be able to call them. > The existing rule means that the entire class interface is visible in=20 > the class declaration, and you have a complete list of everything=20 > (members and friends) that could be affected by an internal=20 > implementation change. >=20 > This rule works against information hiding, but that was not a design=20 > goal of C++ classes. I'm not sure what you do mean by hiding here. If you mean hiding to=20 human, I do not care. If you mean hiding from all the code using a class=20 that something internal to this class has been changed, I think it would=20 be worthwile. It could even lead to header files being more "write protected" than=20 implementation files. There are currently alternatives : - PIMPL : Has an overhead, requires some changes in the class definition=20 to switch from a non-pimpl to a pimpl class. It can still be usefull for=20 private data, and for hiding to the human. - Use only free functions for implementation, pass them all they need in=20 argument : That make function with long argument lists, which are a pain=20 to write and a pain to use. Although I understand the current rules for data, or for virtual,=20 protected of public functions, I believe it would be really easy to=20 relax those rules for private-non virtual functions. --=20 Lo=EFc --- [ 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 ]