linux – How to make Paho MQTT C++ Client Library wait for initial connection?

March 19, 2026admin

I’m using Paho MQTT C++ Client Library on Ubuntu 22.04 and 24.04 to publish messages to remote MQTT broker. Here is the snippet:

#include "mqtt/client.h"

int main() {
  mqtt::client client("192.168.0.19", "", nullptr);
  mqtt::connect_options connOpts;

  connOpts.set_keep_alive_interval(3600);
  connOpts.set_connect_timeout(5);
  connOpts.set_clean_session(true);
  connOpts.set_automatic_reconnect(true);

  try {
    client.connect(connOpts);
  }
  catch (std::exception& e) {
    std::cout << e.what() << std::endl;
  }
}

My test case tries to connect to inactive broker at 192.168.0.19. Despite connect timeout set to 5s and automatic reconnect activated, the program fails immediately with MQTT error [-1]: TCP/TLS connect failure output. It behaves similarily with mqtt::async_client. Is there a way to make it retry for set timeout, i.e. 5s, before failing?

linux – How to make Paho MQTT C++ Client Library wait for initial connection?

March 19, 2026admin

I’m using Paho MQTT C++ Client Library on Ubuntu 22.04 and 24.04 to publish messages to remote MQTT broker. Here is the snippet:

#include "mqtt/client.h"

int main() {
  mqtt::client client("192.168.0.19", "", nullptr);
  mqtt::connect_options connOpts;

  connOpts.set_keep_alive_interval(3600);
  connOpts.set_connect_timeout(5);
  connOpts.set_clean_session(true);
  connOpts.set_automatic_reconnect(true);

  try {
    client.connect(connOpts);
  }
  catch (std::exception& e) {
    std::cout << e.what() << std::endl;
  }
}