keyok.3x man page
keyok — enable or disable a keycode
int keyok(int keycode, bool enable);
This is an extension to the curses library. It permits an application to disable specific keycodes, rather than use the keypad function to disable all keycodes. Keys that have been disabled can be re-enabled.
The keycode must be greater than zero, else ERR is returned. If it does not correspond to a defined key, then ERR is returned. If the enable parameter is true, then the key must have been disabled, and vice versa. Otherwise, the function returns OK.
These routines are specific to ncurses. They were not supported on Version 7, BSD or System V implementations. It is recommended that any code depending on them be conditioned using NCURSES_VERSION.