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 XWIN 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 XPend-
ing, 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
XWIN server.  Any errors generated must be handled by the
error handler.  For each error event received by Xlib, XSync
calls the client application's error handling routine (see
section 8.12.2, Xlib-C Language X Interface).  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

XWIN 3.0               Last change: 9/1/88                 .ie t

     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 XWIN server but have not been removed
     from the event queue.  XPending is identical to
     XEventsQueued with the mode QueuedAfterFlush specified.

SEE ALSO

     XIfEvent(3X11),
     XNextEvent(3X11),
     XPutBackEvent(3X11)
     Xlib - C Language X Interface

XWIN 3.0               Last change: 9/1/88                 .ie t

XWIN 3.0               Last change: 9/1/88                 .ie t