ZMQ pubsub example

//pub.cpp
#include <zmq.hpp>
#include <string>
#include <iostream>
#include <unistd.h>

int main() {
    // Prepare the context and publisher socket
    zmq::context_t context(1);
    zmq::socket_t publisher(context, zmq::socket_type::pub);

    // Bind the socket to an endpoint
    publisher.bind("tcp://*:5556");

    while (true) {
        // Create a message
        std::string msg = "Hello, world!";
        zmq::message_t message(msg.size());
        memcpy(message.data(), msg.data(), msg.size());

        // Send the message
        std::cout << "Sending message: " << msg << std::endl;
        publisher.send(message, zmq::send_flags::none);

        // Sleep for a second before sending the next message
        sleep(1);
    }

    return 0;
}
// sub.cpp
#include <zmq.hpp>
#include <string>
#include <iostream>

int main() {
    // Prepare the context and subscriber socket
    zmq::context_t context(1);
    zmq::socket_t subscriber(context, zmq::socket_type::sub);

    // Connect to the publisher
    subscriber.connect("tcp://localhost:5556");

    // Subscribe to all messages
    subscriber.setsockopt(ZMQ_SUBSCRIBE, "", 0);

    while (true) {
        zmq::message_t message;

        // Receive the message
        subscriber.recv(message, zmq::recv_flags::none);
        std::string msg_str(static_cast<char*>(message.data()), message.size());
        std::cout << "Received message: " << msg_str << std::endl;
    }

    return 0;
}