Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!infonode!doyle
From: doyle@infonode.ingr.com (Doyle Davidson)
Newsgroups: comp.windows.x.motif
Subject: UIL and widgets in callbacks
Message-ID: <1991Apr24.192305.22011@infonode.ingr.com>
Date: 24 Apr 91 19:23:05 GMT
Organization: Intergraph Corp. Huntsville, AL
Lines: 40

Can someone give me a working example of how to pass a widget
as the user data to a callback function from UIL.

My attempts lead to the following error:
        Widget resource invalid as callback tag value

This is part of what I do:
    procedure PrintMyName(any);
    ...
    callbacks
    {
        XmNactivateCallback = procedure PrintMyName(XmPushButton mypb);
    };
where mypb is an XmPushButton object.

On a related note, I have seen code where callbacks are defined as:
    XtCallbackProc mycB(...)
    {
	...
    }
and this does not seem correct since XtCallbackProc is a pointer to a
function that returns void.  My ANSI compiler doesn't like it either.
Shouldn't callbacks simply be defined as:
    void myCB(...)
    {
	...
    }

Doyle
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Doyle C. Davidson              |
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