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XtInsertEventTypeHandler(3Xt)
X11R6
NAME
  XtInsertEventTypeHandler, XtRemoveEventTypeHandler,
  XtRegisterExtensionSelector, XtSetEventDispatcher, XtDispatchEventToWidget
  - extension event handling

SYNOPSIS
  void XtInsertEventTypeHandler(widget, event_type, select_data, proc,
  client_data, position)
	  Widget widget;
	  int event_type;
	  XtPointer select_data;
	  XtEventHandler proc;
	  XtPointer client_data;
	  XtListPosition position;

  void XtRemoveEventTypeHandler(widget, event_type, select_data, proc,
  client_data)
	  Widget widget;
	  int event_type;
	  XtPointer select_data;
	  XtEventHandler proc;
	  XtPointer client_data;

  void XtRegisterExtensionSelector(display, min_event_type, max_event_type,
  proc, client_data)
	  Display* display;
	  int min_event_type;
	  int max_event_type;
	  XtExtensionSelectProc proc;
	  XtPointer client_data;

  XtEventDispatchProc XtSetEventDispatcher(display, event_type, proc)
	  Widget widget;
	  int event_type;
	  XtEventDispatchProc proc;

  Boolean XtDispatchEventToWidget(widget, event)
	  Widget widget;
	  XEvent* event;

ARGUMENTS
  widget
      Specifies the widget for this event handler. Must be of class Core or
      any subclass thereof.

  event_type
      Specifies the event type.

  select_data
      Specifies data used to select or deselect events from the server.

  proc
      Specifies the proc.

  client_data
      Specifies additional data to be passed to the event handler.

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

  display
      Specifies the display.

  min_event_type, max_event_type
      Specifies the range of event types for this extension.

  event
      Specifies a pointer to the event to be dispatched.

DESCRIPTION
  The XtInsertEventTypeHandler function registers a procedure with the
  dispatch mechanism that is to be called when an event that matches the
  specified event_type is dispatched to the specified widget.

  If event_type is one of the core X protocol events then select_data must be
  a pointer to a value of type EventMask, indicating the event mask to be
  used to select for the desired event. This event mask will be included in
  the value returned by XtBuildEventMask. If the widget is realized
  XtInsertEventTypeHandler calls XSelectInput if necessary. Specifying NULL
  for select_data is equivalent to specifying a pointer to an event mask
  containing 0. This is similar to the XtInsertRawEventHandler function.

  If event_type specifies an extension event type then the semantics of the
  data pointed to by select_data are defined by the extension selector
  registered for the specified event type.

  In either case the Intrinsics are not required to copy the data pointed to
  by select_data, so the caller must ensure that it remains valid as long as
  the event handler remains registered with this value of select_data.

  The position argument allows the client to control the order of the
  invocation of event handlers registered for the same event type. If the
  client does not care about the order, it should normally specify
  XtListTail, which registers this event handler after any previously
  registered handlers for this event type.

  The XtRemoveEventTypeHandler function unregisters an even handler
  registered with XtInsertEventTypeHandler for the specified event type. The
  request is ignored if client_data does not match the value given with the
  handler was registered.

  If event_type specifies on of the core X protocol events, select_data must
  be a pointer to a value of type EventMask, indicating the mask to be used
  to deselect for the appropriate event. If the widget is realized,
  XtRemoveEventTypeHandler calls XSelectInput if necessary. Specifying NULL
  for select_data is equivalent to specifying a pointer to an event mask
  containing 0. This is similar to the XtRemoveRawEventHandler function.

  If event_type specifies an extension event type then the semantics of the
  data pointed to by select_data are defined by the extension selector
  registered for the specified event type.

  The XtRegisterExtensionSelector function registers a procedure to arrange
  for the delivery of extension events to widgets.

  If min_event_type and max_event_type match the parameters to a previous
  call to XtRegisterExtensionSelector for the same display, the proc and
  client_data replace the previously registered values. If the range
  specified by min_event_type and max_event_type overlaps the range of the
  parameters to a previous call for the same display in any other way, an
  error results.

  The XtSetEventDispatcher function registers the event dispatcher procedure
  specified by proc for events with the type event_type. The previously
  registered dispatcher (or the default dispatcher if there was no previously
  registered dispatcher) is returned. If proc is NULL, the default procedure
  is restored for the specified type.

  In the future, when XtDispatchEvent is called with an event of event_type,
  the specified proc (or the default dispatcher) will be invoked to determine
  a widget ot which to dispatch the event.

  The XtDispatchEventToWidget function scans the list of registered event
  handlers for the specified widget and calls each handler that has been
  registered for the specified event type, subject to the
  continue_to_dispatch value returned by each handler. The Intrinsics behave
  as if event handlers were registered at the head of the list for Expose,
  NoExpose, GraphicsExpose, and VisibilityNotify events to invoke the
  widget's expose procedure according to the exposure compression rules and
  to update the widget's visible field if visible_interest is True. These
  internal event handlers never set continue_to_dispatch to False.

  XtDispatchEventToWidget returns True if any event handler was called and
  False otherwise.

SEE ALSO
  XtGetKeyboardFocusWidget(3Xt)

  X Toolkit Intrinsics -- C Language Interface

  Xlib -- C Language X Interface

Index for Section 3Xt

Alphabetical listing for X

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