ultrix man page for xsynchronize

XSynchronize(3X11)						     MIT X11R4							XSynchronize(3X11)

Name
       XSynchronize, XSetAfterFunction - enable or disable synchronization

Syntax
       int (*XSynchronize(display, onoff))()
	  Display *display;
	  Bool onoff;

       int (*XSetAfterFunction(display, procedure))()
	  Display *display;
	  int (*procedure)();

Arguments
       display	 Specifies the connection to the X server.

       procedure Specifies the function to be called after an Xlib function that generates a protocol request completes its work.

       onoff	 Specifies a Boolean value that indicates whether to enable or disable synchronization.

Description
       The function returns the previous after function.  If onoff is turns on synchronous behavior.  If onoff is turns off synchronous behavior.

       The specified procedure is called with only a display pointer.  returns the previous after function.

See Also
       XSetErrorHandler(3X11)
       X Window System: The Complete Reference, Second Edition, Robert W. Scheifler and James Gettys

																XSynchronize(3X11)