mqtt斷線重連:
需要在連接的時候設置三個參數.
重連間隔單位爲秒。
在例程裏
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);
}
conn_opts的設置一定要緊跟在MQTTAsync_connect()之前MQTTAsync_create()之後,否則會在發送或者訂閱時產生段錯誤.