Function sc_get_challenge

pub unsafe extern "C" fn sc_get_challenge(
    card: *mut sc_card,
    rndout: *mut u8,
    len: size_t,
) -> c_int

Gets challenge from the card (normally random data). @param card struct sc_card object on which to issue the command @param rndout buffer for the returned random challenge @param len length of the challenge @return SC_SUCCESS on success and an error code otherwise