define_key - define a keycode
int define_key(char *definition, int keycode);
This is an extension to the curses library. It permits an application
to define keycodes with their corresponding control strings, so that
the ncurses library will interpret them just as it would the predefined
codes in the terminfo database.
If the given string is null, any existing definition for the keycode is
removed. Similarly, if the given keycode is negative or zero, any
existing string for the given definition is removed.
The keycode must be greater than zero, else ERR is returned.
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.