-may be macros.
-.SH RETURN VALUE
-All of these functions return the integer \fBOK\fP upon successful completion.
-If unsuccessful, they return \fBERR\fP.
-.PP
-X/Open defines no error conditions.
-.PP
-In this implementation,
-these functions return an error
-.bP
-if the window pointer is null,
-.bP
-if its timeout expires without having any data, or
-.bP
-if the associated call to
-\fBwget_wch\fP
-failed.
-.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.