-These routines insert the character \fIch\fR before the character under the
-cursor. All characters to the right of the cursor are moved one space to the
-right, with the possibility of the rightmost character on the line being lost.
-The insertion operation does not change the cursor position.
-.SH RETURN VALUE
-All routines that return an integer return \fBERR\fR upon failure and OK (SVr4
-specifies only "an integer value other than \fBERR\fR") upon successful
-completion, unless otherwise noted in the preceding routine descriptions.
+These functions insert the
+.I curses
+character
+.I ch
+at the cursor in the specified window
+.I win
+(or
+.BR \%stdscr ).
+The character previously at the cursor and any to its right move one
+cell to the right;
+the rightmost character on the line is discarded.
+The cursor does not advance.
+.SH "RETURN VALUE"
+These functions return \fBOK\fP on success and \fBERR\fP on failure.
+.PP
+Functions taking a
+.I \%WINDOW
+pointer argument fail if the pointer is
+.BR NULL .
+.PP
+Functions prefixed with \*(``mv\*('' first perform cursor movement using
+\fB\%wmove\fP and fail if the position
+.RI ( y ,
+.IR x )
+is outside the window.