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From: swick@ATHENA.MIT.EDU (Ralph R. Swick)
Newsgroups: comp.windows.x
Subject: Re: Inheriting class extensions
Message-ID: <9002022140.AA03077@lyre.MIT.EDU>
Date: 2 Feb 90 21:40:22 GMT
References: <158@gazette.bcm.tmc.edu>
Sender: root@athena.mit.edu (Wizard A. Root)
Organization: DEC/MIT Project Athena
Lines: 14

> Do I declare a copy of the ShellClassExtensionRec 
> in my own widget file and then make each field of that 
> XtInheritWhatever?

Exactly.  The class extension record is logically (or perhaps
not so logically :-) appended to the class part structure; each
class needs its own copy of the extension record(s), just as
it needs its own copy of the superclass part structures.

> (Are there XtInheritWhatever's defined for 
> all of the fields of the extension?)

Yes.  As of R4, there is only one such field, and its
inherit constant is XtInheritRootGeometryManager.