Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!taumet!steve
From: steve@taumet.com (Stephen Clamage)
Newsgroups: comp.lang.c++
Subject: Re: translator error
Message-ID: <558@taumet.com>
Date: 19 Jan 91 23:31:49 GMT
References: <1991Jan18.205053.22916@linus.mitre.org>
Organization: Taumetric Corporation, San Diego
Lines: 22

fkuhl@maestro.mitre.org (F. S. Kuhl) writes:

>Why does the translator (Sun packaging of AT&T 2.0) object to the
>following?  I define in a base class SBName a virtual operator

>virtual SBName& operator = (const char *);

>which I intend to inherit in a derived class, ObjectName...

operator= is a special case.  It must be a nonstatic member function
of a class, and is not inherited (E&S 13.4.3, p 334-5).

Briefly, assignment has a predefined meaning for a class object
(memberwise copy).  You are permitted to specify your own assignment
operator for a class (which may do anything at all, and which need not
do any assignment).  It is too dangerous to blindly inherit a base
class assignment operator.  If the programmer specified special
assignment procedures for a class, the compiler cannot make any
assumptions about what should be done for a derived class.
-- 

Steve Clamage, TauMetric Corp, steve@taumet.com