From 8296983202859318644 X-Google-Thread: f78e5,84b1489db50fe20d X-Google-Attributes: gidf78e5,public,usenet X-Google-Language: ENGLISH,ASCII Path: g2news1.google.com!news3.google.com!feeder3.cambrium.nl!feeder3.cambrium.nl!feed.tweaknews.nl!63.218.45.11.MISMATCH!nx02.iad01.newshosting.com!newshosting.com!news.alt.net!comp-std-cpp-robomod!not-for-mail From: =?iso-8859-1?q?Daniel_Kr=FCgler?= Newsgroups: comp.std.c++ Subject: Re: static member function and const Date: Tue, 13 Nov 2007 10:29:27 CST Organization: http://groups.google.com Lines: 47 Approved: Fergus Henderson , moderator of comp.std.c++ Message-ID: <1194950311.581663.175280@v2g2000hsf.googlegroups.com> References: <1194932017.215138.261760@e9g2000prf.googlegroups.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8bit X-Trace: posting.google.com 1194950311 22954 127.0.0.1 (13 Nov 2007 10:38:31 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Tue, 13 Nov 2007 10:38:31 +0000 (UTC) Return-Path: X-Authentication-Warning: mulga.csse.unimelb.edu.au: fjh set sender to devnull@stump.algebra.com using -f X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) X-Original-To: std-c++@mailman.ucar.edu Delivered-To: std-c++@mailman.ucar.edu X-SMTP-Auth: no User-Agent: G2/1.0 X-HTTP-UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.9) Gecko/20071025 Firefox/2.0.0.9,gzip(gfe),gzip(gfe) Complaints-To: groups-abuse@google.com Injection-Info: v2g2000hsf.googlegroups.com; posting-host=195.137.177.243; posting-account=ps2QrAMAAAA6_jCuRt2JEIpn5Otqf_w0 X-Virus-Scanned: amavisd-new at ucar.edu X-Virus-Scanned: amavisd-new at csse.unimelb.edu.au X-MIME-Autoconverted: from quoted-printable to 8bit by mulga.csse.unimelb.edu.au id lADAcw5P028267 X-Virus-Scanned: amavisd-new at csse.unimelb.edu.au Xref: g2news1.google.com comp.std.c++:9602 On Nov 13, 8:43 am, "subramanian10...@yahoo.com, India" wrote: > why can't a static member function be declared as const ? > We can declare a non-static member function as const, > to indicate that it does not modify the non-mutable data > members of a class. Slightly imprecise: The const-qualification specifies whether the member function does potentially modify a given instance of a class, more specifically a const member function can be thought of having a hidden this-pointer to the *const* class type and acting with this pointer. From this we can easily recognize that mutable operations conflict with this const- qualification. Static member functions don't have any this pointer. > In the same way, is there a provision > to indicate that a static member function does not modify > the static data members but only uses their values ? In C++ there does not exist the concept of a class instance, which would be necessary to make that approach reasonable. *If* C++ would express classes itself as first-class objects (some other languages do this with a so-called meta class concept), than we would probably distinguish "pure" static member functions (which are similar to free functions and reflect the current concept of static function members) from "class-static" functions, which would have a hidden pointer to the meta class object (and not an individual this pointer). For similar reasons C++ does not support virtual static functions (which would make sense, if you consider polymorphic meta-classes). If you need such behaviour, you have to create your own meta-class approach, which is solvable via pure language means. HTH & Greetings from Bremen, Daniel Kr�gler --- [ 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.comeaucomputing.com/csc/faq.html ]