hpux man page for xtremoveeventhandler

XtRemoveEventHandler()													    XtRemoveEventHandler()

Name
  XtRemoveEventHandler - remove an event handler, or change the conditions under which it is called.

Synopsis
  void XtRemoveEventHandler(w, event_mask, nonmaskable, proc, client_data)
	 Widget w;
	 EventMask event_mask;
	 Boolean nonmaskable;
	 XtEventHandler proc;
	 XtPointer client_data;

Inputs
  w	    Specifies the widget for which this handler is registered.	Must be of class Core or any subclass thereof.

  event_mask
	    Specifies the events for which to unregister this handler.

  nonmaskable
	    Specifies whether this handler should be unregistered for nonmaskable events.

  proc	    Specifies the handler procedure.

  client_data
	    Specifies the client data with which the procedure was registered.

Description
  XtRemoveEventHandler()  stops  the  proc/client_data	event handler pair registered with XtAddEventHandler() or XtInsertEventHandler() from
  being called from widget w in response to the events specified in event_mask.  In addition, if nonmaskable is True, then the	handler  will
  no  longer  be  called  in response to the nonmaskable events: GraphicsExpose, NoExpose, SelectionClear, SelectionRequest, SelectionNotify,
  ClientMessage, and MappingNotify.

  A handler is removed only if both the procedure proc and client_data match a previously registered handler/data pair.  If a handler  to  be
  removed  fails  to  match  a	procedure, or if it has been registered with a different value of client_data, XtRemoveEventHandler() returns
  without reporting an error.

  XtRemoveEventHandler() accepts the special value XtAllEvents in the event_handler argument as a signal that the  event  handler  should  no
  longer  be called in response to any maskable events.  This value should not be combined with other event mask bits, and should not be used
  to select events in other functions.

  If the widget is realized, and no other handler requires events of any of the specified types, XtRemoveEventHandler() calls XSelectInput(),
  as necessary to prevent the widget from receiving further events of those types.

Usage
  Note	that  XtRemoveEventHandler() does not necessarily remove an event handler; rather, it modifies the conditions for which it is called.
  To prevent an event handler from being called at all, call XtRemoveEventHandler() with an event_mask of XtAllEvents and  with  nonmaskable
  True.

  To  remove  or  change  the  event  mask for a "raw" event handler registered with XtAddRawEventHandler() or XtInsertRawEventHandler(), use
  XtRemoveRawEventHandler().

Structures
  Each of the event types listed in the table below set a single bit in an event mask.	The event_mask argument is formed by combining	these
  symbols  with the bitwise OR operator ( ).  Note that the nonmaskable event types do not appear in this table and cannot be requested in an
  event mask.

NoEventMask		Button1MotionMask      StructureNotifyMask
KeyPressMask		Button2MotionMask      ResizeRedirectMask
KeyReleaseMask		Button3MotionMask      SubstructureNotifyMask
ButtonPressMask 	Button4MotionMask      SubstructureRedirectMask
ButtonReleaseMask	Button5MotionMask      FocusChangeMask

EnterWindowMask 	ButtonMotionMask       PropertyChangeMask
LeaveWindowMask 	KeymapStateMask        ColormapChangeMask
PointerMotionMask	ExposureMask	       OwnerGrabButtonMask
PointerMotionHintMask	VisibilityChangeMask

See Appendix C, Event Reference, for more information on event types and masks.

  In addition to these standard X event masks, the Intrinsics define a special value for use by this function:

     /* XtAllEvents is valid only for XtRemoveEventHandler and
      * XtRemoveRawEventHandler; don't use it to select events!
      */
     #define XtAllEvents ((EventMask) -1L)

See Also
  XtAddEventHandler(1), XtInsertEventHandler(1), XtRemoveRawEventHandler(1),
  XtEventHandler(2).

Xt - Event Handling													    XtRemoveEventHandler()