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XIfEvent(3X11)		       XLIB FUNCTIONS		       XIfEvent(3X11)



NAME
  XIfEvent, XCheckIfEvent, XPeekIfEvent - check the event queue with a predi-
  cate procedure

SYNTAX
  XIfEvent(display, event_return, predicate, arg)
	Display *display;
	XEvent *event_return;
	Bool (*predicate)();
	XPointer arg;

  Bool XCheckIfEvent(display, event_return, predicate, arg)
	Display *display;
	XEvent *event_return;
	Bool (*predicate)();
	XPointer arg;

  XPeekIfEvent(display, event_return, predicate, arg)
	Display *display;
	XEvent *event_return;
	Bool (*predicate)();
	XPointer arg;

ARGUMENTS

  arg	    Specifies the user-supplied argument that will be passed to the
	    predicate procedure.

  display   Specifies the connection to the X server.

  event_return
	    Returns either a copy of or	 the matched event's associated
	    structure.

  predicate Specifies the procedure that is to be called to determine if the
	    next event in the queue matches what you want.

DESCRIPTION
  The XIfEvent function completes only when the specified predicate procedure
  returns True for an event, which indicates an event in the queue matches.
  XIfEvent flushes the output buffer if it blocks waiting for additional
  events.  XIfEvent removes the matching event from the queue and copies the
  structure into the client-supplied XEvent structure.

  When the predicate procedure finds a match, XCheckIfEvent copies the
  matched event into the client-supplied XEvent structure and returns True.
  (This event is removed from the queue.) If the predicate procedure finds no
  match, XCheckIfEvent returns False, and the output buffer will have been
  flushed.  All earlier events stored in the queue are not discarded.

  The XPeekIfEvent function returns only when the specified predicate pro-
  cedure returns True for an event.  After the predicate procedure finds a
  match, XPeekIfEvent copies the matched event into the client-supplied
  XEvent structure without removing the event from the queue.  XPeekIfEvent
  flushes the output buffer if it blocks waiting for additional events.




SEE ALSO
  XAnyEvent(3X11), XNextEvent(3X11), XPutBackEvent(3X11) XSendEvent(3X11)
  Xlib - C Language X Interface































































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