+ X/Open does not define any error conditions. In this im-
+ plementation
+
+ <STRONG>is_linetouched</STRONG>
+ returns an error if the window pointer is
+ null, or if the line number is outside the
+ window. Note that ERR is distinct from TRUE
+ and FALSE, which are the normal return values
+ of this function.
+
+ <STRONG>wtouchln</STRONG>
+ returns an error if the window pointer is
+ null, or if the line number is outside the
+ window.
+