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EZ_AddWidgetCallBack(3)         EZWGL Functions        EZ_AddWidgetCallBack(3)

NAME
       EZ_AddWidgetCallBack, EZ_RemoveWidgetCallBack,
       EZ_RemoveAllWidgetCallBacks  - register/remove callbacks associated to
       a widget

SYNOPSIS
       #include <EZ.h>

       void EZ_AddWidgetCallBack( EZ_Widget *widget,
            int which, EZ_CallBack callback, void *clientdata, int location)
       void EZ_AddWidgetCallBack00( EZ_Widget *widget,
            int which, EZ_CallBack callback, void *clientdata, int location)
       void EZ_RemoveWidgetCallBack( EZ_Widget *widget,
            int which, EZ_CallBack callback, void *clientdata)
       void EZ_RemoveWidgetCallBack00( EZ_Widget *widget,
            int which, EZ_CallBack callback, void *clientdata)
       void EZ_RemoveAllWidgetCallBacks( EZ_Widget *widget, int which)
       void EZ_RemoveAllWidgetCallBacks00( EZ_Widget *widget, int which)

ARGUMENTS
       widget  Specifies an EZ widget.

       callback  Specifies a callback.

       clientdata  Specifies an clientdata to be passed to the callback.

       which  Specifies a callback list.

       location  Specifies when the callback is to be called relative to other
       previousely registered callbacks.

DESCRIPTION
       An callback is a procedure of the following prototype:

           void (* callback)(void *object, void *data)

       EZ_AddWidgetCallBack registers a callback to a widget.  There are three
       callback lists associated to a widget: an EZ_CALLBACK list, an
       EZ_MOTION_CALLBACK list and an EZ_DESTROY_CALLBACK list. Motion
       callbacks are invoked whenever the the selection item changes. Normal
       callbacks are called when a Button1 press occurs on the widget window
       or a selection is made. Destroy callbacks are invoked at the time a
       widget is destroyed. If location is 0, the callback will be put in
       front of all previously registered callbacks. If location is 1, the
       callback will be inserted at the end of all previousely registered
       callbacks.

       For composite widget, EZ_AddWidgetCallBack registers the callback to
       the most appropriate inter widget. To register a callback to a
       composite widget itself, use EZ_AddWidgetCallBack00.

       EZ_RemoveWidgetCallBack deletes a callback from the specified callback
       list. The specified callback will be deleted only if both the procedure
       and the client data match.

       For composite widget, EZ_RemoveWidgetCallBack removes the callback from
       the most appropriate inter widget. To remove a callback from a
       composite widget's callback list, use EZ_RemoveWidgetCallBack00.

       EZ_RemoveAllCallBacks deletes all callbacks from the specified callback
       list.

SEE ALSO
       EZ_AddEventHandler(3)

EZWGL                                                  EZ_AddWidgetCallBack(3)