-<H2>RETURN VALUES</H2><PRE>
- All routines return the integer <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> on
- success.
+<H2>RETURN VALUE</H2><PRE>
+ All functions return the integer <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG>
+ on success.
+
+ X/Open does not define any error conditions. This imple-
+ mentation returns an error
+
+ <STRONG>o</STRONG> if the window pointer is null or
+
+ <STRONG>o</STRONG> if the string pointer is null or
+
+ <STRONG>o</STRONG> if the corresponding calls to <STRONG>wadd_wch</STRONG> return an er-
+ ror.
+
+ 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.