+ X/Open defines no error conditions. In this implementa-
+ tion, an error may be returned if it cannot allocate
+ enough memory for the buffer used to format the results.
+ It will return an error if the window pointer is null.
+
+ 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.
+