The function redraw-frame redisplays the entire contents of a
given frame. See section Frames.
Even more powerful is redraw-display:
t, all devices will have their frames checked.
Processing user input takes absolute priority over redisplay. If you call these functions when input is available, they do nothing immediately, but a full redisplay does happen eventually--after all the input has been processed.
Normally, suspending and resuming XEmacs also refreshes the screen. Some terminal emulators record separate contents for display-oriented programs such as XEmacs and for ordinary sequential display. If you are using such a terminal, you might want to inhibit the redisplay on resumption. See section Suspending XEmacs.
nil means yes, nil
means no.
The above functions do not actually cause the display to be updated;
rather, they clear out the internal display records that XEmacs
maintains, so that the next time the display is updated it will be
redrawn from scratch. Normally this occurs the next time that
next-event or sit-for is called; however, a display update
will not occur if there is input pending. See section Command Loop.