NAME

       XtAddEventHandler,       XtAddRawEventHandler,       XtRemoveEventHandler,       XtRemoveRawEventHandler,
       XtInsertEventHandler, XtInsertRawEventHandler - add and remove event handlers

SYNTAX

       #include <X11/Intrinsic.h>

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

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

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

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

       void XtInsertEventHandler(Widget w,  EventMask  event_mask,  Boolean  nonmaskable,  XtEventHandler  proc,
              XtPointer client_data, XtListPosition position);

       void  XtInsertRawEventHandler(Widget  w,  EventMask event_mask, Boolean nonmaskable, XtEventHandler proc,
              XtPointer client_data, XtListPosition position);

       typedef enum { XtListHead, XtListTail } XtListPosition;

ARGUMENTS

       client_data
                 Specifies additional data to be passed to the client's event handler.

       event_mask
                 Specifies the event mask for which to call or unregister this procedure.

       nonmaskable
                 Specifies a Boolean value that indicates whether this procedure should be called or removed  on
                 the   nonmaskable   events   (   GraphicsExpose,  NoExpose,  SelectionClear,  SelectionRequest,
                 SelectionNotify, ClientMessage, and MappingNotify).

       proc      Specifies the procedure that is to be added or removed.

       w         Specifies the widget for which this event handler is being registered.

       position  Specifies when the event handler is to  be  called  relative  to  other  previously  registered
                 handlers.

DESCRIPTION

       The  XtAddEventHandler  function  registers  a procedure with the dispatch mechanism that is to be called
       when an event that matches the mask occurs  on  the  specified  widget.   If  the  procedure  is  already
       registered  with  the same client_data, the specified mask is ORed into the existing mask.  If the widget
       is realized, XtAddEventHandler calls XSelectInput, if necessary.

       The XtAddRawEventHandler function is similar to XtAddEventHandler except that  it  does  not  affect  the
       widget's  mask  and never causes an XSelectInput for its events.  Note that the widget might already have
       those mask bits set because of other nonraw event handlers registered on it.

       The XtRemoveRawEventHandler function stops the specified procedure from receiving the  specified  events.
       Because  the  procedure is a raw event handler, this does not affect the widget's mask and never causes a
       call on XSelectInput.

       XtInsertEventHandler is identical  to  XtAddEventHandler  with  the  additional  position  argument.   If
       position  is  XtListHead,  the  event  handler  is  registered to that it will be called before any event
       handlers that were previously registered for the same widget.   If  position  is  XtListTail,  the  event
       handler  is  registered to be called after any previously registered event handlers.  If the procedure is
       already registered with the same client_data value, the specified mask augments the existing mask and the
       procedure is repositioned in the list.

       XtInsertRawEventHandler is similar to XtInsertEventHandler except that it does not  modify  the  widget's
       event  mask  and  never  causes  an  XSelectInput  for the specified events.  If the procedure is already
       registered with the same client_data value, the  specified  mask  augments  the  existing  mask  and  the
       procedure is repositioned in the list.

SEE ALSO

       XtAppNextEvent(3), XtBuildEventMask(3)
       X Toolkit Intrinsics - C Language Interface
       Xlib - C Language X Interface

X Version 11                                       libXt 1.2.1                              XtAddEventHandler(3)