hpux man page for xcheckwindowevent

XCheckWindowEvent()													       XCheckWindowEvent()

Name
  XCheckWindowEvent - remove the next event matching both passed window and passed mask; don't wait.

Synopsis
  Bool XCheckWindowEvent(display, w, event_mask, event_return)
	Display *display;
	Window w;
	long event_mask;
	XEvent *event_return;

Arguments
  display   Specifies a connection to an X server; returned from XOpenDisplay().

  w	    Specifies the window ID.  The event must match both the passed window and the passed event mask.

  event_mask
	    Specifies the event mask.  See XSelectInput() for a list of mask elements.

  event_return
	    Returns the XEvent structure.

Returns
  True if a matching event is found, else False.

Description
  XCheckWindowEvent()  removes the next event in the queue that matches both the passed window and the passed mask.  If such an event exists,
  it is copied into an XEvent supplied by the caller.  Other events earlier in the queue are not discarded.

  If a matching event is found, XCheckWindowEvent() returns True.  If no such event has been  queued,  it  flushes  the  request  buffer  and
  returns False, without waiting.

  XCheckWindowEvent()  cannot  return ClientMessage, MappingNotify, SelectionClear, SelectionNotify, or SelectionRequest events because these
  event types are by definition unmaskable.

  For more information, see Volume One, Chapter 8, Events.

See Also
  XQLength(), XAllowEvents(), XCheckIfEvent(), XCheckMaskEvent(), XCheckTypedEvent(), XCheckTypedWindowEvent(), XEventsQueued(), XGetInputFo-
  cus(),  XGetMotionEvents(),  XIfEvent(),  XMaskEvent(), XNextEvent(), XPeekEvent(), XPeekIfEvent(), XPending(), XPutBackEvent(), XSelectIn-
  put(), XSendEvent(), XSetInputFocus(), XSynchronize(), XWindowEvent().

Xlib - Input Handling													       XCheckWindowEvent()