set_to_generic_if_null
set_to_generic_if_null(device, open);
set_to_generic_if_null(device, write);
set_to_generic_if_null(device, close);
set_to_generic_if_null(device, write_room);
set_to_generic_if_null(device, chars_in_buffer);
set_to_generic_if_null(device, wait_until_sent);
set_to_generic_if_null(device, read_bulk_callback);
set_to_generic_if_null(device, write_bulk_callback);
set_to_generic_if_null(device, process_read_urb);
set_to_generic_if_null(device, prepare_write_buffer);