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From: pjp@sloth.mlb.semi.harris.com (Pat J. Pinchera)
Newsgroups: comp.windows.x.motif
Subject: Dialog Unmap/'Close' Question and Problem -REVISITED-
Keywords: UnmapCallbacks, Dialogs, Window Menu Button
Message-ID: <1991May3.175805.27038@mlb.semi.harris.com>
Date: 3 May 91 17:58:05 GMT
Sender: pjp@mlb.semi.harris.com
Followup-To: comp.windows.x.motif
Organization: Interface & Control Systems, Inc.
Lines: 55
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Dialog Unmap/'Close' Question:
Note: this a repost of a problem that I had a couple of months ago.
A working solution is proposed below.

When I create 3 Form dialogs, with the hierarchy described below, I attach
UnmapCallbacks to them which take care of some cleaning up for each window
when it is unmapped.  This callback is activated when 
I select the 'Close' option (Alt+F4) from the Window Menu Button 
(the 'Dash' button in the upper left corner of each window). 

The problem is when I 'Close' a dialog that has 1 or more children dialogs,
(i.e. "dialog1" or "dialog2"); the UnmapCallback *DOES NOT GET CALLED* for
the children dialogs, even though they disappear. For example, 'Close'
dialog2, then dialog2 & dialog3 disappear, and dialog2 UnmapCallback gets 
called but dialog3 UnmapCallback does *NOT*.
I tried the DestroyCallback, but that doesn't seem to get activated for the
children either.

               +---------+
               | dialog1 |
               | +---------+        Widget Hierarchy:
               | | dialog2 |                   dialog1 is parent of dialog2
               | | +---------+                 dialog2 is parent of dialog3
               | | | dialog3 |
               +-| |         |
                 | |         |
                 +-|         |
                   |         |
                   +---------+

What can I do so that the children callbacks get activated as well, even though
I didn't explicitly 'Close' them? (They need to do some cleaning up too!)

I did receive one reply telling me to try XmAddWMProtocolCallback, and
check the WM_DELETE_WINDOW protocol. Well I tried several combinations
of this, but to no avail. 

However, I did find a working solution to my problem:

Add a destroy callback to each dialog that contains all of the "clean-up
actions" that you want to take place. Also attach an unmap callback to 
each dialog, and in it, only have the statement 'XtDestroyWidget(w)', 
where w is the widget passed to the callback.  What results is the unmap 
callback gets called, destroys the widget that you 'closed', and as a 
result, destroys the children widgets. Since we've attached a destroy 
callback, it gets called for each child dialog, and voila', clean-up 
actions take place for each dialog!!!

If you see any problems with the implementation, OR have a better, more
efficient, or more portable method, please respond. I'm not particularly
proud of this solution, but hey, it *does* work.

Patrick Pinchera
Interface & Control Systems, Inc.
Melbourne, FL