XFlush(3) XLIB FUNCTIONS XFlush(3)
NAME
XFlush, XSync, XEventsQueued, XPending - handle output buffer or
event queue
SYNTAX
int XFlush(Display *
display);
int XSync(Display *
display, Bool
discard);
int XEventsQueued(Display *
display, int
mode);
int XPending(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 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.
SEE ALSO
AllPlanes(3),
XIfEvent(3),
XNextEvent(3),
XPutBackEvent(3) Xlib - C Language X InterfaceX Version 11 libX11 1.8.10 XFlush(3)
