XFlush 3X11 __xorgversion__ XLIB FUNCTIONS XFlush XSync XEventsQueued XPending handle output buffer or event queue int XFlush ( Display *display ); int XSync ( Display *display , Bool discard ); int XEventsQueued ( Display *display , int mode ); int XPending ( Display *display ); discard Specifies a Boolean value that indicates whether  XSync  discards all events on the event queue. display Specifies the connection to the X server. mode Specifies the mode. You can pass  QueuedAlready ,  QueuedAfterFlush , or  QueuedAfterReading . The  XFlush  function flushes the output buffer. Most client applications need not use this function because the output buffer is automatically flushed as needed by calls to  XPending ,  XNextEvent , and  XWindowEvent . Events generated by the server may be enqueued into the library's event queue. The  XSync  function flushes the output buffer and then waits until all requests have been received and processed by the X server. Any errors generated must be handled by the error handler. For each protocol error received by Xlib,  XSync  calls the client application's error handling routine (see section 11.8.2). Any events generated by the server are enqueued into the library's event queue. Finally, if you passed  False ,  XSync  does not discard the events in the queue. If you passed  True ,  XSync  discards all events in the queue, including those events that were on the queue before  XSync  was called. Client applications seldom need to call  XSync . If mode is  QueuedAlready ,  XEventsQueued  returns the number of events already in the event queue (and never performs a system call). If mode is  QueuedAfterFlush ,  XEventsQueued  returns the number of events already in the queue if the number is nonzero. If there are no events in the queue,  XEventsQueued  flushes the output buffer, attempts to read more events out of the application's connection, and returns the number read. If mode is  QueuedAfterReading ,  XEventsQueued  returns the number of events already in the queue if the number is nonzero. If there are no events in the queue,  XEventsQueued  attempts to read more events out of the application's connection without flushing the output buffer and returns the number read.  XEventsQueued  always returns immediately without I/O if there are events already in the queue.  XEventsQueued  with mode  QueuedAfterFlush  is identical in behavior to  XPending .  XEventsQueued  with mode  QueuedAlready  is identical to the  XQLength  function. The  XPending  function returns the number of events that have been received from the X server but have not been removed from the event queue.  XPending  is identical to  XEventsQueued  with the mode  QueuedAfterFlush  specified. AllPlanes(3X11), XIfEvent(3X11), XNextEvent(3X11), XPutBackEvent(3X11) Xlib - C Language X Interface