Returns the Window number of a Window.
Optional. Window reference. Defaults to the current Window.
An integer, the Window number of the Window.
If Window 2 is the current Window:
getwnum - 1
performs a derivative of Window 1.
wref = refwindow(w3);
n = getwnum(wref);
n == 3
GETWNUM is useful in SPL routines and command files where the current Window number may not be obvious.
See GETWINNAME to return a string that contains the symbolic or numeric name of the Window.