我運行訂閱「Hello World」的簡單mqtt發佈者c代碼。無法訂閱mqtt中的多個主題
MQTT SUBSCRIBER1:
mosquitto_sub -h xx.xx.xx.xx -t "mq_test"
。連續我運行相同的MQTT發佈者的代碼在另一個位置,並用不同的主題,以相同的主機訂閱。
MQTT subscriber2用戶:
mosquitto_sub -h xx.xx.xx.xx -t "mq_t"
當我開始第二個發行計劃,第一MQTT訂閱停止。 爲什麼會出現這個問題,我認爲可以訂閱多個主題。
MQTT出版商的C代碼:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <MQTTClient.h>
#define ADDRESS "tcp://xx.xx.xx.xx:abcd"
#define CLIENTID "ExampleClientPub"
#define TOPIC "mq_test" //"mq_t"
#define PAYLOAD "Hello World!"
#define QOS 1
#define TIMEOUT 10000L
int main(int argc, char* argv[])
{
MQTTClient client;
MQTTClient_connectOptions conn_opts = MQTTClient_connectOptions_initializer;
int rc = 0;
MQTTClient_create(&client, ADDRESS, CLIENTID,
MQTTCLIENT_PERSISTENCE_NONE, NULL);
conn_opts.keepAliveInterval = 5;
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_message pubmsg = MQTTClient_message_initializer;
MQTTClient_deliveryToken token;
while(1){
rc = 0;
pubmsg.payload = PAYLOAD;
pubmsg.payloadlen = strlen(PAYLOAD);
pubmsg.qos = QOS;
pubmsg.retained = 0;
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[%d] delivered\n", token,rc);
}
MQTTClient_disconnect(client, 10000);
MQTTClient_destroy(&client);
return rc;
}
您可以添加訂閱代碼片段嗎? – Vardit