Usage example

Step 1: Initialization

1. Add the header file.
   

   ……
   ……
   
   #include "aiot_ntp_api.h"

   
   

2. Configure underlying dependencies and log output.

       aiot_sysdep_set_portfile(&g_aiot_sysdep_portfile);
       aiot_state_set_logcb(demo_state_logcb);

3. Call aiot_ntp_init to create an NTP handle.

       ntp_handle = aiot_ntp_init();
       if (ntp_handle == NULL) {
           demo_mqtt_stop(&mqtt_handle);
           printf("aiot_ntp_init failed\n");
           return -1;
       }

Step 2: Configure features

Call aiot_ntp_setopt to configure the following features.

• Associate the MQTT connection handle.
• Set the time zone.
• Configure a message callback.
• Configure a status monitoring callback.

1. Associate the MQTT connection handle.
   
   Important Before you configure NTP service parameters, ensure that device authentication information and other related parameters are configured. For more information, see Configure MQTT connection parameters.

   •     aiot_ntp_setopt(ntp_handle, AIOT_NTPOPT_MQTT_HANDLE, mqtt_handle);

   • Configuration item	Example	Description
     AIOT_NTPOPT_MQTT_HANDLE	mqtt_handle	The NTP service sends requests over an MQTT connection. This configuration item associates the MQTT connection handle.

   
   
2. Set the time zone.

   •     int8_t      time_zone = 8;
         ……
         ……
         aiot_ntp_setopt(ntp_handle, AIOT_NTPOPT_TIME_ZONE, (int8_t *)&time_zone);

   • Configuration item	Example	Description
     AIOT_NTPOPT_TIME_ZONE	time_zone	The time zone of the device. The time zone defined in the sample code is time_zone=8, which sets the device time zone to UTC+8. Set the device time zone by setting the value of time_zone. Valid values: -12 to 12. For example, -3 specifies UTC-3.

3. Configure a message callback.

   •     aiot_ntp_setopt(ntp_handle, AIOT_NTPOPT_RECV_HANDLER, (void *)demo_ntp_recv_handler);

   • Configuration item	Example value	Description
     AIOT_NTPOPT_RECV_HANDLER	demo_ntp_recv_handler	This function is called when an NTP service message is received.

4. .
   1. 
      

      void demo_ntp_event_handler(void *handle, const aiot_ntp_event_t *event, void *userdata)
      {
          switch (event->type) {
              case AIOT_NTPEVT_INVALID_RESPONSE: {
                  printf("AIOT_NTPEVT_INVALID_RESPONSE\n");
              }
              break;
              case AIOT_NTPEVT_INVALID_TIME_FORMAT: {
                  printf("AIOT_NTPEVT_INVALID_TIME_FORMAT\n");
              }
              break;
              default: {
      
              }
          }
      }

      
      
   2. 
      

      •     aiot_ntp_setopt(ntp_handle, AIOT_NTPOPT_EVENT_HANDLER, (void *)demo_ntp_event_handler);

      • Configuration item	Example value	Description
        AIOT_NTPOPT_EVENT_HANDLER	demo_ntp_event_handler	When the device connection status changes, the corresponding processing logic defined in this callback function is executed.

      
      

Step 3: Send a request

Call aiot_ntp_send_request to send a request message that contains the device's current time to the server over the topic /ext/ntp/${YourProductKey}/${YourDeviceName}/request. This call uses the parameters that you configured in the previous step.

Link SDK automatically reports the current device time using system interfaces.

    res = aiot_ntp_send_request(ntp_handle);
    if (res < STATE_SUCCESS) {
        aiot_ntp_deinit(&ntp_handle);
        demo_mqtt_stop(&mqtt_handle);
        return -1;
    }

Step 4: Receive the acknowledgement

After the device receives the NTP service message, the demo_ntp_recv_handler callback function is triggered to process the message.

• IoT Platform sends a message that contains the time to the device over the topic /ext/ntp/${YourProductKey}/${YourDeviceName}/response.

• The data structure of the time message is aiot_ntp_recv_t. See the sample code for an example of how to retrieve the time.

• The sample code in this topic parses the returned message, which is available in the packet parameter, and then prints the time message.

void demo_ntp_recv_handler(void *handle, const aiot_ntp_recv_t *packet, void *userdata)
{
    switch (packet->type) {
        /* TODO: Parse and store the values of year, month, day, hour, minute, and second in the current time zone. */
        case AIOT_NTPRECV_LOCAL_TIME: {
            printf("local time: %llu, %02d/%02d/%02d-%02d:%02d:%02d:%d\n",
                   (long long unsigned int)packet->data.local_time.timestamp,
                   packet->data.local_time.year,
                   packet->data.local_time.mon, packet->data.local_time.day, packet->data.local_time.hour, packet->data.local_time.min,
                   packet->data.local_time.sec, packet->data.local_time.msec);
        }
        break;

        default: {

        }
    }
}

Step 5: Exit the program

Call aiot_ntp_deinit to destroy the NTP handle.

    res = aiot_ntp_deinit(&ntp_handle);
    if (res < STATE_SUCCESS) {
        demo_mqtt_stop(&mqtt_handle);
        printf("aiot_ntp_deinit failed: -0x%04X\n", -res);
        return -1;
    }