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How to Subscribe the Message from Server in MQTT?

The Message from Server in MQTT

Contiki Cooja Steps to Subscribe The Message from Server in MQTT


   When a client publishes a message on a topic then the broker will distribute that message to any connected clients that have subscribed to that topic.

Source code

Step 1: Open a file at location:contiki/ mqtt-sn-contiki/main_core.c

// To subscribe

mqtt_sn_init(); // initiation

char *topic =”/topic_1″;

mqtt_sn_sub(topic,0); //subscribe

Step 2: Initiate the subscriber
contiki/ mqtt-sn-contiki/mqtt_sn.c
void init_sub(void *ptr)
resp_con_t mqtt_sn_sub_send(char *topic, uint8_t qos)
Subscribes the messages from broker.

Step 3: Function receives the topics.
void mqtt_sn_callback(char *topic, char *message)
Recived topic and message from server or broker

Step 4: Run the simulation

Publisher send the message to server
subscribed successfully