+ X/Open does not define any error conditions. This imple-
+ mentation returns an error if the window pointer is null
+ or if the string pointer is null or if the corresponding
+ calls to <STRONG>waddch</STRONG> return an error.
+
+ Functions with a "mv" prefix first perform a cursor move-
+ ment using <STRONG>wmove</STRONG>, and return an error if the position is
+ outside the window, or if the window pointer is null.
+