mqtt_settings settings = { .host = "192.168.0.1", // or domain, ex: "google.com", .port = 1883, .client_id = "mqtt_client_id", .username = "user", .password = "pass", .clean_session = 0, .keepalive = 120, //second .lwt_topic = "/lwt", // = "" for disable lwt, will don't care other options .lwt_msg = "offline", .lwt_qos = 0, .lwt_retain = 0, .connected_cb = connected_cb, // trigger when client connected to broker with valid infomations .disconnected_cb = disconnected_cb, //trigger when client disconnect from broker .reconnect_cb = reconnect_cb, //trigger when client reconnect - not implement yet .subscribe_cb = subscribe_cb, //trigger when client subscribe a topic successful  .publish_cb = publish_cb, //trigger when client publish data to channel successful  .data_cb = data_cb //trigger when client receive data from channel has subscribed }; mqtt_client *client = mqtt_start(&settings);

void data_cb(void *self, void *params) { mqtt_client *client = (mqtt_client *)self; mqtt_event_data_t *event_data = (mqtt_event_data_t *)params; } typedef struct mqtt_event_data_t { char* topic; //point to topic  char* data; //point to data uint16_t topic_length; uint16_t data_length; //current packet length uint16_t data_offset; //current packet offset uint16_t data_total_length; //total packet length } mqtt_event_data_t;