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From: johnson@p.cs.uiuc.edu
Newsgroups: comp.lang.c++
Subject: Re: fixing pitfall in virtual members
Message-ID: <77300020@p.cs.uiuc.edu>
Date: 17 Feb 89 18:19:00 GMT
References: <89@<DOVE>
Lines: 13
Nf-ID: #R:<DOVE:89:p.cs.uiuc.edu:77300020:000:545
Nf-From: p.cs.uiuc.edu!johnson    Feb 17 12:19:00 1989


Webster Dove described the problem that can occur when the implementer
of a derived class declares a virtual member function with the wrong
name.  Briefly, the compiler does not issue any warnings but uses
the function inherited from the base class, and the new function never
gets called.

One way to minimize this problem is to make base classes abstract
(i.e. their virtual functions are only place-holders) and to make
the virtual functions give error messages if they are ever called.
This technique has worked well for us.

Ralph Johnson