get_led_data
err = get_led_data(envmon_fd, &id, cmd, &led_state,
err = get_led_data(envmon_fd, &id, cmd, &led_state, NULL);
static int get_led_data(int envmon_fd, envmon_handle_t *id, int cmd,
PICL_VOLATILE, MAX_STATE_LEN, class, get_led_data,
static int get_led_data(ptree_rarg_t *arg, void *result);