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From:	softbrek AT hathi DOT informatik DOT rwth-aachen DOT de (Hans-Bernhard Broeker)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Problem Creating C++ Program
Date:	26 Jun 1995 10:00:38 GMT
Organization:	RWTH -Aachen / Rechnerbetrieb Informatik
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References:	<3sckr5$3ui AT hq DOT hq DOT af DOT mil>
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To:	djgpp AT sun DOT soe DOT clarkson DOT edu
Dj-Gateway:	from newsgroup comp.os.msdos.djgpp

David DOT Hurt AT comm DOT hq DOT af DOT mil (Lt David Hurt) writes:

>Hello, All

>Sorry if this is a really stupid question, but I have been having a 
>problem getting a program to link.  All my individual files compile
>correctly, but when I link I get an error message complaining that
>"__pure_virtual" is an unresolved symbol. 

>P.S.  If it makes any difference, I am using the SLList template for
>a linked list.  I create several lists of <Component *>

Well, I'm no C++ guru, but I think you're doing something wrong in
your code: the error message you describe occurs because you called
a method declared virtual, and not overloaded with a proper, *non-virtual*
method later. Such a 'pure virtual' method is to be understood as a
kind of place-holder in the father-classes, to be replaced by actual
implementations in *all* final child-classes. Your source seems to 
lack these implementations.

If memory serves me well, there should also be some documentation on
this issue in the "g++ internals" info-file, that should be (is it?)
in gcc263dc.zip.

Hope this I got this right.

Hans-Bernhard Broeker

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