Paho MQTT C Client Library
Asynchronous publication example
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "MQTTClient.h"
#define ADDRESS "tcp://localhost:1883"
#define CLIENTID "ExampleClientPub"
#define TOPIC "MQTT Examples"
#define PAYLOAD "Hello World!"
#define QOS 1
#define TIMEOUT 10000L
volatile MQTTClient_deliveryToken deliveredtoken;
void delivered(void *context, MQTTClient_deliveryToken dt)
{
printf("Message with token value %d delivery confirmed\n", dt);
deliveredtoken = dt;
}
int msgarrvd(void *context, char *topicName, int topicLen, MQTTClient_message *message)
{
int i;
char* payloadptr;
printf("Message arrived\n");
printf(" topic: %s\n", topicName);
printf(" message: ");
payloadptr = message->payload;
for(i=0; i<message->payloadlen; i++)
{
putchar(*payloadptr++);
}
putchar('\n');
MQTTClient_free(topicName);
return 1;
}
void connlost(void *context, char *cause)
{
printf("\nConnection lost\n");
printf(" cause: %s\n", cause);
}
int main(int argc, char* argv[])
{
MQTTClient client;
int rc;
MQTTClient_create(&client, ADDRESS, CLIENTID,
conn_opts.keepAliveInterval = 20;
conn_opts.cleansession = 1;
MQTTClient_setCallbacks(client, NULL, connlost, msgarrvd, delivered);
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;
deliveredtoken = 0;
MQTTClient_publishMessage(client, TOPIC, &pubmsg, &token);
printf("Waiting for publication of %s\n"
"on topic %s for client with ClientID: %s\n",
PAYLOAD, TOPIC, CLIENTID);
while(deliveredtoken != token);
MQTTClient_disconnect(client, 10000);
return rc;
}
MQTTClient_message::retained
int retained
Definition: MQTTClient.h:309
MQTTClient_message_initializer
#define MQTTClient_message_initializer
Definition: MQTTClient.h:327
MQTTClient_connectOptions::keepAliveInterval
int keepAliveInterval
Definition: MQTTClient.h:757
MQTTClient_message::payloadlen
int payloadlen
Definition: MQTTClient.h:274
MQTTClient_freeMessage
void MQTTClient_freeMessage(MQTTClient_message **msg)
MQTTCLIENT_PERSISTENCE_NONE
#define MQTTCLIENT_PERSISTENCE_NONE
Definition: MQTTClientPersistence.h:74
MQTTClient_message
Definition: MQTTClient.h:266
MQTTClient_connectOptions_initializer
#define MQTTClient_connectOptions_initializer
Definition: MQTTClient.h:875
MQTTClient_message::qos
int qos
Definition: MQTTClient.h:290
MQTTClient_deliveryToken
int MQTTClient_deliveryToken
Definition: MQTTClient.h:257
MQTTClient_setCallbacks
int MQTTClient_setCallbacks(MQTTClient handle, void *context, MQTTClient_connectionLost *cl, MQTTClient_messageArrived *ma, MQTTClient_deliveryComplete *dc)
MQTTClient_message::payload
void * payload
Definition: MQTTClient.h:276
MQTTClient
void * MQTTClient
Definition: MQTTClient.h:246
MQTTCLIENT_SUCCESS
#define MQTTCLIENT_SUCCESS
Definition: MQTTClient.h:137
MQTTClient_destroy
void MQTTClient_destroy(MQTTClient *handle)
MQTTClient_connectOptions
Definition: MQTTClient.h:735
MQTTClient_publishMessage
int MQTTClient_publishMessage(MQTTClient handle, const char *topicName, MQTTClient_message *msg, MQTTClient_deliveryToken *dt)
MQTTClient_connect
int MQTTClient_connect(MQTTClient handle, MQTTClient_connectOptions *options)
MQTTClient_disconnect
int MQTTClient_disconnect(MQTTClient handle, int timeout)
MQTTClient_connectOptions::cleansession
int cleansession
Definition: MQTTClient.h:779
MQTTClient_free
void MQTTClient_free(void *ptr)
MQTTClient.h
MQTTClient_create
int MQTTClient_create(MQTTClient *handle, const char *serverURI, const char *clientId, int persistence_type, void *persistence_context)