+.PP
+X/Open defines no error conditions.
+In this implementation,
+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.
+.PP
+Functions with a "mv" prefix first perform a cursor movement using
+\fBwmove\fP, and return an error if the position is outside the window,
+or if the window pointer is null.