https://invisible-island.net/ncurses/man/
key_defined(3x) Library calls key_defined(3x)
key_defined - test whether a curses keycode is defined
#include <curses.h> int key_defined(const char *definition);
This is an extension to the curses library. It permits an application to determine if a string is currently bound to any keycode.
If the string is bound to a keycode, its value (greater than zero) is returned. If no keycode is bound, zero is returned. If the string conflicts with longer strings which are bound to keys, -1 is returned.
This 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 them be conditioned using NCURSES_VERSION.
define_key(3x)
Thomas Dickey ncurses 6.4 2023-09-23 key_defined(3x)