+If \fIn\fR is \-1, then the entire string will be added.
+.SH RETURN VALUE
+All functions return the integer \fBERR\fR upon failure and \fBOK\fR on success.
+.PP
+X/Open does not define any error conditions.
+This implementation returns an error
+.bP
+if the window pointer is null or
+.bP
+if the string pointer is null or
+.bP
+if the corresponding calls to \fBwadd_wch\fP return an error.