pub unsafe extern "C" fn crypt_keyslot_add_by_keyfile_device_offset( cd: *mut crypt_device, keyslot: c_int, keyfile: *const c_char, keyfile_size: size_t, keyfile_offset: u64, new_keyfile: *const c_char, new_keyfile_size: size_t, new_keyfile_offset: u64) -> c_int