gistfile1.txt

static void print_mgos_ro_vars(struct json_out *out, va_list *ap) {
  struct mgos_ro_vars *p = va_arg(*ap, struct mgos_ro_vars *);
  json_printf(out,
              "{mac_address: %Q, arch: %Q, fw_version: %Q, fw_timestamp: %Q, "
              "fw_id: %Q}",
              p->mac_address, p->arch, p->fw_version, p->fw_timestamp,
              p->fw_id);
}

static void main_timer_cb(void *arg) {
  (void) arg;
  time_t now = time(0);
  const char *fw_timestamp = mgos_sys_ro_vars_get_fw_timestamp();
  mgos_mqtt_pubf("test1", 1, false, "{fw_timestamp: %Q, now: %lu}", fw_timestamp,
                 now);
  int arr[] = {1, 2, 3, 4};
  mgos_mqtt_pubf("test2", 1, false, "{now: %lu, mgos_ro_vars: %M, array: %M}",
                 now, print_mgos_ro_vars, &mgos_sys_ro_vars, json_printf_array,
                 arr, sizeof(arr), sizeof(arr[0]), "%d");
}

/*
 mosquitto_sub -t test1 -t test2
{"fw_timestamp": "2018-08-06T07:36:37Z", "now": 1533541034}
{"now": 1533541034, "mgos_ro_vars": {"mac_address": "30AEA4323558", "arch": "esp32", "fw_version": "1.0", "fw_timestamp": "2018-08-06T07:36:37Z", "fw_id": "20180806-073637/???"}, "array": [1, 2, 3, 4]}
*/