+ X/Open does not define any error conditions.
+
+ In this implementation, those functions that have a window
+ pointer will return an error if the window pointer is
+ null.
+
+ <STRONG>wclrtoeol</STRONG>
+ returns an error if the cursor position is
+ about to wrap.
+
+ <STRONG>wsetscrreg</STRONG>
+ returns an error if the scrolling region lim-
+ its extend outside the window.
+
+ X/Open does not define any error conditions. This imple-
+ mentation returns an error if the window pointer is null.