files/mqttdoc/MQTTAsync/man/man3/publish.3

.TH "publish" 3 "Thu Sep 13 2018" "Paho Asynchronous MQTT C Client Library" \" -*- nroff -*-
.ad l
.nh
.SH NAME
publish \- Publication example 

.PP
.nf
#include <stdio\&.h>
#include <stdlib\&.h>
#include <string\&.h>
#include "MQTTAsync\&.h"

#define ADDRESS     "tcp://localhost:1883"
#define CLIENTID    "ExampleClientPub"
#define TOPIC       "MQTT Examples"
#define PAYLOAD     "Hello World!"
#define QOS         1
#define TIMEOUT     10000L

volatile MQTTAsync_token deliveredtoken;

int finished = 0;

void connlost(void *context, char *cause)
{
        MQTTAsync client = (MQTTAsync)context;
        MQTTAsync_connectOptions conn_opts = MQTTAsync_connectOptions_initializer;
        int rc;

        printf("\nConnection lost\n");
        printf("     cause: %s\n", cause);

        printf("Reconnecting\n");
        conn_opts\&.keepAliveInterval = 20;
        conn_opts\&.cleansession = 1;
        if ((rc = MQTTAsync_connect(client, &conn_opts)) != MQTTASYNC_SUCCESS)
        {
                printf("Failed to start connect, return code %d\n", rc);
                finished = 1;
        }
}


void onDisconnect(void* context, MQTTAsync_successData* response)
{
        printf("Successful disconnection\n");
        finished = 1;
}


void onSend(void* context, MQTTAsync_successData* response)
{
        MQTTAsync client = (MQTTAsync)context;
        MQTTAsync_disconnectOptions opts = MQTTAsync_disconnectOptions_initializer;
        int rc;

        printf("Message with token value %d delivery confirmed\n", response->token);

        opts\&.onSuccess = onDisconnect;
        opts\&.context = client;

        if ((rc = MQTTAsync_disconnect(client, &opts)) != MQTTASYNC_SUCCESS)
        {
                printf("Failed to start sendMessage, return code %d\n", rc);
                exit(EXIT_FAILURE);
        }
}


void onConnectFailure(void* context, MQTTAsync_failureData* response)
{
        printf("Connect failed, rc %d\n", response ? response->code : 0);
        finished = 1;
}


void onConnect(void* context, MQTTAsync_successData* response)
{
        MQTTAsync client = (MQTTAsync)context;
        MQTTAsync_responseOptions opts = MQTTAsync_responseOptions_initializer;
        MQTTAsync_message pubmsg = MQTTAsync_message_initializer;
        int rc;

        printf("Successful connection\n");

        opts\&.onSuccess = onSend;
        opts\&.context = client;

        pubmsg\&.payload = PAYLOAD;
        pubmsg\&.payloadlen = strlen(PAYLOAD);
        pubmsg\&.qos = QOS;
        pubmsg\&.retained = 0;
        deliveredtoken = 0;

        if ((rc = MQTTAsync_sendMessage(client, TOPIC, &pubmsg, &opts)) != MQTTASYNC_SUCCESS)
        {
                printf("Failed to start sendMessage, return code %d\n", rc);
                exit(EXIT_FAILURE);
        }
}


int main(int argc, char* argv[])
{
        MQTTAsync client;
        MQTTAsync_connectOptions conn_opts = MQTTAsync_connectOptions_initializer;
        MQTTAsync_message pubmsg = MQTTAsync_message_initializer;
        MQTTAsync_token token;
        int rc;

        MQTTAsync_create(&client, ADDRESS, CLIENTID, MQTTCLIENT_PERSISTENCE_NONE, NULL);

        MQTTAsync_setCallbacks(client, NULL, connlost, NULL, NULL);

        conn_opts\&.keepAliveInterval = 20;
        conn_opts\&.cleansession = 1;
        conn_opts\&.onSuccess = onConnect;
        conn_opts\&.onFailure = onConnectFailure;
        conn_opts\&.context = client;
        if ((rc = MQTTAsync_connect(client, &conn_opts)) != MQTTASYNC_SUCCESS)
        {
                printf("Failed to start connect, return code %d\n", rc);
                exit(EXIT_FAILURE);
        }

        printf("Waiting for publication of %s\n"
         "on topic %s for client with ClientID: %s\n",
         PAYLOAD, TOPIC, CLIENTID);
        while (!finished)
                #if defined(WIN32) || defined(WIN64)
                        Sleep(100);
                #else
                        usleep(10000L);
                #endif

        MQTTAsync_destroy(&client);
        return rc;
}

.fi
.PP