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From: pasturel@sctc.com (Pierre Pasturel)
Newsgroups: comp.windows.x.motif
Subject: Re: Determining children widget IDs (Summary)
Message-ID: <1991Jan2.185621.20296@sctc.com>
Date: 2 Jan 91 18:56:21 GMT
References: <20.277b089c@idicl1.idi.battelle.org> <21.277e1314@idicl1.idi.battelle.org>
Organization: Secure Computing Technology Corporation
Lines: 41

grywalski@idicl1.idi.battelle.org writes:

>#include <X11/IntrinsicP.h>
>#include <X11/Intrinsic.h>
>#include <X11/Composite.h>
>#include <X11/CompositeP.h>

>WidgetList GetChildren(w)
>    CompositeWidget w;
>{
>    return w->composite.children;
>}
>int GetNumChildren(w)
>    CompositeWidget w;
>{
>    return w->composite.num_children;
>}


As an observation, I thought that one should never include both
IntrinsicP.h and Intrinisic.h (and the same goes with Composite include
files). 

One of the OSF/Motif 1.0 manuals had a demo program which did include
both, and this lead to much frustration later on when  I found out
that some fucntion protocols (e.g. XtScreen, XtDisplay,..) in Intrinsic.h 
were being redefined by
macro defines in IntrinsicP.h by #include-ing the former followed by the
latter, and this resulted in core dumps when I tried using the functions.

I was told later by someone on this newsgroup never to include both, but
I can't remember exactly why.
Does it depend on your environment (i.e. will it work for some but not for
others) ????

Its problems like these that should be inserted in a Commonly-Asked-Questions-
and-Problems. I could list more things that beginner Motif programmers should
look out for, but that would take too long  :)

Pierre
pasturel@sctc.com