XFlush(3X11)

NAME
       XFlush, XSync, XEventsQueued, XPending - handle output
       buffer or event queue

SYNTAX
       XFlush(display)
             Display *display;

       XSync(display, discard)
             Display *display;
             Bool discard;

       int XEventsQueued(display, mode)
            Display *display;
            int mode;

       int XPending(display)
             Display *display;

ARGUMENTS
       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.

DESCRIPTION
       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 gener-
       ated 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 out-
       put 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 iden-
       tical 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.

SEE ALSO
       AllPlanes(3X11) XIfEvent(3X11) XNextEvent(3X11) XPut- 
       BackEvent(3X11) 
       Xlib - C Language X Interface