Hello World server in C++

//
// Hello World server in C++
// Binds REP socket to tcp://*:5555
// Expects "Hello" from client, replies with "World"
//

#include <zmq.hpp>
#include <string>
#include <iostream>
#ifndef _WIN32
#include <unistd.h>
#else
#include <windows.h>

#define sleep(n) Sleep(n)
#endif

int main () {
// Prepare our context and socket
zmq::context_t context (1);
zmq::socket_t socket (context, ZMQ_REP);
socket.bind ("tcp://*:5555");

while (true) {
zmq::message_t request;

// Wait for next request from client
socket.recv (&request);
std::cout << "Received Hello" << std::endl;

// Do some 'work'
sleep(1);

// Send reply back to client
zmq::message_t reply (5);
memcpy (reply.data (), "World", 5);
socket.send (reply);
}
return 0;
}