hpux man page for xpending

XPending()																XPending()

Name
  XPending - return the number of pending events.

Synopsis
  int XPending(display)
	Display *display;

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

Returns
  The number of events.

Description
  XPending()  returns the number of events that have been received by Xlib from the server, but not yet removed from the queue.  If there are
  no events on the queue, XPending() flushes the request buffer, and returns the number of events transferred to the input queue as a  result
  of the flush.

  The QLength macro or XQLength() returns the number of events on the queue, but without flushing the request buffer first.

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

See Also
  XQLength(),	XAllowEvents(),   XCheckIfEvent(),   XCheckMaskEvent(),  XCheckTypedEvent(),  XCheckTypedWindowEvent(),  XCheckWindowEvent(),
  XEventsQueued(), XGetInputFocus(), XGetMotionEvents(), XIfEvent(),  XMaskEvent(),  XNextEvent(),  XPeekEvent(),  XPeekIfEvent(),  XPutBack-
  Event(), XSelectInput(), XSendEvent(), XSetInputFocus(), XSynchronize(), XWindowEvent().

Xlib - Input Handling															XPending()