cat1连接mqtt的C语言代码
时间: 2024-06-08 18:11:59 浏览: 12
以下是一个简单的C语言程序,用于连接到MQTT代理并发布和订阅主题:
```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <MQTTClient.h>
#define ADDRESS "tcp://localhost:1883"
#define CLIENTID "ExampleClientSub"
#define TOPIC "MQTT Examples"
#define QOS 1
#define TIMEOUT 10000L
volatile MQTTClient_deliveryToken deliveredtoken;
void deliveryCompleteCallback(void* context, MQTTClient_deliveryToken dt) {
printf("Message with token value %d delivery confirmed\n", dt);
deliveredtoken = dt;
}
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);
}
MQTTClient_subscribe(client, TOPIC, QOS);
pubmsg.payload = "Hello world!";
pubmsg.payloadlen = strlen(pubmsg.payload);
pubmsg.qos = QOS;
pubmsg.retained = 0;
deliveredtoken = 0;
MQTTClient_setCallbacks(client, NULL, deliveryCompleteCallback, NULL, NULL);
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), pubmsg.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;
}
```
这个程序使用了MQTTClient C库,可以在这里找到更多关于如何使用它的信息:https://www.eclipse.org/paho/clients/c/
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