I'm writing an MQTT client which simply connects to the broker, and publishes or subscribes to a topic. Here in the program, I try to Connect to Broker and then call the loop_forever() function and is execute successfully and gets a connect acknowledgment at the client side, but instead of loop_forever(), when I called the loop_Start() for the new thread to execute all callback, it failed with the error MOSQ_ERR_NOT_SUPPORTED. Here is a code for the MQTT client for publisher and subscriber.
myMosq.h
#include <mosquittopp.h>
#include <mosquitto.h>
class myMosq : public mosqpp::mosquittopp
{
private:
const char* host;
const char* id;
const char* topic;
int port;
int keepalive;
void on_connect(int rc);
void on_disconnect(int rc);
void on_publish(int mid);
void on_message(const struct mosquitto_message* message);
public:
myMosq(const char* id, const char* _topic, const char* host, int port);
~myMosq();
bool send_message(const char* _message);
};
myMosq.cpp
#include <iostream>
myMosq::myMosq(const char* _id, const char* _topic, const char* _host, int _port) : mosquittopp(_id)
{
mosqpp::lib_init() ; // Mandatory initialization for mosquitto library
this->keepalive = 60; // Basic configuration setup for myMosq class
this->id = _id;
this->port = _port;
this->host = _host;
this->topic = _topic;
int result;
result = connect_async(host, port, keepalive); // non blocking connection to broker request
if (result != MOSQ_ERR_SUCCESS)
{
std::cerr << "Error in connect_async" << std::endl;
}
result = loop_start(); // Start thread managing connection / publish/subscribe
//result = loop_forever(); // Start thread managing connection / publish / subscribe
if (result != MOSQ_ERR_SUCCESS)
{
std::cerr << "Error in loop_start: " << (mosq_err_t)result << std::endl;
}
};
myMosq::~myMosq()
{
loop_stop(); // Kill the thread
mosqpp::lib_cleanup(); // Mosquitto library cleanup
}
bool myMosq::send_message(const char* _message)
{
int ret = publish(NULL, this->topic, strlen(_message), _message, 1, false);
return (ret == MOSQ_ERR_SUCCESS);
}
void myMosq::on_disconnect(int rc)
{
std::cout << ">> myMosq - disconnection(" << rc << ")" << std::endl;
}
void myMosq::on_connect(int rc)
{
if (rc == 0){
std::cout << ">> myMosq - connected with server" << std::endl;
}
else{
std::cout << ">> myMosq - Impossible to connect with server(" << rc << ")" << std::endl;
}
}
void myMosq::on_publish(int mid)
{
std::cout << ">> myMosq - Message (" << mid << ") succeed to be published " << std::endl;
}
void myMosq::on_message(const struct mosquitto_message* message)
{
std::cout << "Topic: " << message->topic << " Payload: " << message->payload << " Payload_Length: " << message->payloadlen << std::endl;
}
main.cpp
#include <windows.h>
#include <string>
#include "myMosq.h"
void MQTT_Subscriber(myMosq& i_client)
{
int result = i_client.subscribe(nullptr, "logrequest", 1);
if (result != MOSQ_ERR_SUCCESS)
{
std::cout << "mosquitto : subscriber error: " << mosqpp::strerror(result) << std::endl;
}
else
{
std::cout << "mosquitto : subscriber : " << result << std::endl;
}
}
void MQTT_Publisher(myMosq& i_client)
{
int i = 1;
std::string message = "I am mosquitto VS pub";
while (1)
{
std::string message1 = message + std::to_string(i);
if (!i_client.send_message(message1.c_str()))
{
break;
}
Sleep(2000);
i++;
}
}
int main()
{
std::cout << "In main" << std::endl;
std::shared_ptr<myMosq> m_client = std::make_shared<myMosq>("dev3_", "logrequest", "127.0.0.1", 1883);
//MQTT_Publisher(m_client);
//MQTT_Subscriber(m_client);
while (1);
return 0;
}
I used visual studio 2022 and added all mosquito dependencies to the project.
while running program with the loop_start() function I get this error:
**Error in loop_start: 10**
