+.RS
+.TP 5
+\fBungetch\fP
+returns an error
+if there is no more room in the FIFO.
+.TP 5
+\fBwgetch\fP
+returns an error
+if the window pointer is null, or
+if its timeout expires without having any data.
+.RE
+.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.