xtaddeventhandler(1) [hpux man page]

XtAddEventHandler() XtAddEventHandler()

Name
XtAddEventHandler - register a procedure to be called when specified events occur on a widget.

Synopsis
void XtAddEventHandler(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 event handler is being registered. Must be of class Core or any subclass thereof.

event_mask
Specifies the event type that will trigger the handler.

nonmaskable
Specifies whether this procedure should be called on nonmaskable event types.

proc Specifies the handler procedure.

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

Description
XtAddEventHandler() registers the procedure proc and the data client_data with the Intrinsics event dispatching mechanism. When an event
of one of the types set in event_mask occurs on the window of the widget w, proc will be invoked and client_data passed as one of its argu-
ments. If the window of the widget is not already receiving events of the specified types, XtAddEventHandler() calls XSelectInput() to
ensure that they will be delivered. Additionally, if the handler is registered with the nonmaskable argument True, then it will also be
invoked when any of the nonmaskable event types occur. These events are GraphicsExpose, NoExpose, SelectionClear, SelectionRequest, Selec-
tionNotify, ClientMessage, and MappingNotify. Ordinarily, nonmaskable events are of interest only to the Intrinsics.

If the specified procedure/data pair has already been registered for this widget, then the event_mask argument augments the event mask
already registered for the handler, and the procedure will only be called once for any particular event. The same procedure may be regis-
tered multiple times with different values of client_data, and each instance will be treated as a separate handler.

See XtEventHandler(2) for an explanation of how to write an event handler procedure.

Usage
Neither applications nor widgets often need to use event handlers. Using action procedures and translation tables provides a more flexible
way to respond to input events.

The Intrinsics do not specify the order in which event handlers will be called when an event arrives. As of Release 4, however, the func-
tion XtInsertEventHandler() will register an event handler that will be called before or after all previously registered handlers.

An event handler can be removed with XtRemoveEventHandler().

Structures
Each of the event mask symbols 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.

See Also
XtAddRawEventHandler(1), XtInsertEventHandler(1), XtRemoveEventHandler(1),
XtEventHandler(2).

Xt - Event Handling XtAddEventHandler()

Check Out this Related Man Page

XtInsertEventHandler()													    XtInsertEventHandler()

Name
  XtInsertEventHandler - register an event handler procedure that receives events before or after all previously registered event handlers.

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

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

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

  nonmaskable
	    Specifies whether this procedure should be called on nonmaskable events

  proc	    Specifies the procedure that is to be called.

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

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

Availability
  Release 4 and later.

Description
  XtInsertEventHandler()  registers  the  procedure  proc  and the data client_data with the Intrinsics event dispatching mechanism.  When an
  event of one of the types set in event_mask occurs on the window of the widget w, proc will be invoked and client_data passed as one of its
  arguments.

  The argument position specifies where in the list of event handlers proc should be inserted.	If it is XtListHead, proc will be inserted at
  the beginning of the list and will be called before all previously registered handlers.  If it is XtListTail, proc will be inserted at  the
  end of the list and will be called after all previously registered handlers.

  If the procedure is already registered with the same client_data, the specified event_mask augments the existing mask, and the procedure is
  repositioned in the list according to position.

  XtInsertEventHandler() is identical to XtAddEventHandler() with the additional position argument.  See XtAddEventHandler() for more  infor-
  mation.

  See XtEventHandler(2) for an explanation of how to write an event handler procedure.

Usage
  Neither applications nor widgets often need to use event handlers.  Using action procedures and translation tables provides a more flexible
  way to respond to input events.

Structures
  The XtListPosition type is as follows.

     typedef enum {
	 XtListHead,
	 XtListTail
     } XtListPosition;

  See XtAddEventHandler() for a list of bits that can be set in the event_mask argument.

See Also
  XtAddEventHandler(1), XtAddRawEventHandler(1), XtInsertRawEventHandler(1), XtRemoveEventHandler(1), XtRemoveRawEventHandler(1).

Xt - Event Handling													    XtInsertEventHandler()

Linux and UNIX Man Pages

xtaddeventhandler(1) [hpux man page]

Check Out this Related Man Page