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From: ems@socrates.JPL.NASA.gov (Eric Slimko)
Newsgroups: comp.windows.x.motif
Subject: Accessing internal structure of List
Keywords: LIST, INTERNAL STRUCTURE, WIDGET
Message-ID: <1990Oct4.225724.28489@elroy.jpl.nasa.gov>
Date: 4 Oct 90 22:57:24 GMT
Sender: news@elroy.jpl.nasa.gov (Usenet)
Reply-To: ems@socrates.jpl.nasa.gov
Organization: Jet Propulsion Laboratory, NASA/Caltech
Lines: 35
Nntp-Posting-Host: socrates.jpl.nasa.gov

I am writing a routine that does (supposedly) some
work with the internal structure of a List Widget.
Unfortunately, I am having problems with accessing parts
of the structure-- some turn up 0 while others are fine.
Here's a small example of the routine that's giving me problems:

#include <X11/Intrinsic.h>
#include <X11/IntrinsicP.h>
#include <Xm/Xm.h>
#include <Xm/XmP.h>
#include <Xm/List.h>
#include <Xm/ListP.h>

void ListInfo(w)
XmListWidget(w)
{
   printf("Last Hightlighted Item:%d", w->list.LastHLItem);
}

(Yup, I do have a item highlighted before this is called)

This kind of thing works with some of the values, like StartItem
and visibleItemCount, but fails for others, like LastHLItem
and itemCount.  Mostly, I get 0, but sometimes I turn up with a random
number like 163384, which leads me to believe I am not accessing the
correct structure...I have written Widgets before, and this is
how I accessed them in their private routines, so I don't see what
gives.

Please Help!

Thanks in advance,
-- 
Eric Slimko               |  Jet Propulsion Laboratories
ems@socrates.jpl.nasa.gov |  NASA/CalTech