XSync() XSync()
Name
XSync - flush the request buffer and wait for all events and errors to be processed by the server.
Synopsis
XSync(display, discard)
Display *display;
int discard;
Arguments
display Specifies a connection to an X server; returned from XOpenDisplay().
discard Specifies whether XSync() discards all events on the input queue. This argument is either True or False.
Description
XSync() flushes the request buffer, then waits until all events and errors resulting from previous calls have been received and processed
by the X server. Events are placed on the input queue. The client's XError routine is called once for each error received.
If discard is True, XSync() discards all events on the input queue (including those events that were on the queue before XSync() was
called).
XSync() is sometimes used with window manipulation functions (by the window manager) to wait for all resulting exposure events. Very few
clients need to use this function.
See Also
XFlush().
Xlib - Output Buffer XSync()
Check Out this Related Man Page
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 automati-
cally 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 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 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 Interface
X Version 11 libX11 1.6.0 XFlush(3)