+The \fBuse_legacy_coding\fP function allows the caller to
+change the output of \fBunctrl\fP.
+.PP
+Likewise, the \fBmeta\fP function allows the caller to change the
+output of \fBkeyname\fP, i.e.,
+it determines whether to use the `M\-' prefix
+for ``meta'' keys (codes in the range 128 to 255).
+Both \fBuse_legacy_coding\fP and \fBmeta\fP succeed only after
+curses is initialized.
+X/Open Curses does not document the treatment of codes 128 to 159.
+When treating them as ``meta'' keys
+(or if \fBkeyname\fP is called before initializing curses),
+this implementation returns strings ``M\-^@'', ``M\-^A'', etc.
+.PP
+The \fBkeyname\fP function may return the names of user-defined
+string capabilities which are defined in the terminfo entry via the \fB\-x\fP
+option of \fBtic\fP.
+This implementation automatically assigns at run-time keycodes to
+user-defined strings which begin with "k".
+The keycodes start at KEY_MAX, but are not guaranteed to be
+the same value for different runs because user-defined codes are
+merged from all terminal descriptions which have been loaded.
+The \fBuse_extended_names\fP function controls whether this data is
+loaded when the terminal description is read by the library.
+.PP
+The \fBnofilter\fP routine is specific to ncurses.
+It was not supported on Version 7, BSD or System V implementations.
+It is recommended that any code depending on ncurses extensions
+be conditioned using NCURSES_VERSION.