【MQTT编程】消息Publish实践：Synchronous publication同步发布示例-蒲公英云

【MQTT编程】消息Publish实践：Synchronous publication同步发布示例

编程框架

Using the client
Applications that use the client library typically use a similar structure:
1）Create a client object
2）Set the options to connect to an MQTT server
3）Set up callback functions if multi-threaded (asynchronous mode) operation is being used (see Asynchronous vs synchronous client applications).
4）Subscribe to any topics the client needs to receive
5）Repeat until finished:
Publish any messages the client needs to
Handle any incoming messages
6）Disconnect the client
7）Free any memory being used by the client

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "MQTTClient.h"
#define ADDRESS     "tcp://192.168.1.101:1883"
#define CLIENTID    "ExampleClientPub"
#define TOPIC       "MQTT_Examples"
#define PAYLOAD     "Hello MQTT!"
#define QOS         1
#define TIMEOUT     10000L
int main(int argc, char* argv[])
{
    MQTTClient client;
    MQTTClient_connectOptions conn_opts = MQTTClient_connectOptions_initializer;
    MQTTClient_message pubmsg = MQTTClient_message_initializer;
    MQTTClient_deliveryToken token;
    int rc;
    MQTTClient_create(&client, ADDRESS, CLIENTID,
        MQTTCLIENT_PERSISTENCE_NONE, NULL);
    conn_opts.keepAliveInterval = 20;
    conn_opts.cleansession = 1;
    if ((rc = MQTTClient_connect(client, &conn_opts)) != MQTTCLIENT_SUCCESS)
    {
        printf("Failed to connect, return code %d\n", rc);
        exit(EXIT_FAILURE);
    }
    pubmsg.payload = PAYLOAD;
    pubmsg.payloadlen = strlen(PAYLOAD);
    pubmsg.qos = QOS;
    pubmsg.retained = 0;
    while (1)
    {
        MQTTClient_publishMessage(client, TOPIC, &pubmsg, &token);
        printf("Waiting for up to %d seconds for publication of %s\n"
                "on topic %s for client with ClientID: %s\n",
                (int)(TIMEOUT/1000), PAYLOAD, TOPIC, CLIENTID);
        rc = MQTTClient_waitForCompletion(client, token, TIMEOUT);
        printf("Message with delivery token %d delivered\n", token);
        sleep(1);
    }
    MQTTClient_disconnect(client, 10000);
    MQTTClient_destroy(&client);
    return rc;
}