XSynchronize - Man Page

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

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

display

Specifies the connection to the X server.

procedure

Specifies the procedure to be called.

onoff

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

The XSynchronize function returns the previous after function. If onoff is True, XSynchronize turns on synchronous behavior. If onoff is False, XSynchronize turns off synchronous behavior.

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

XSetErrorHandler(3)
Xlib - C Language X Interface

XSetErrorHandler(3).

The man page XSetAfterFunction(3) is an alias of XSynchronize(3).