Weather Update Server (with sleep)

wuserver.cpp

//
//  Weather update server in C++
//  Binds PUB socket to tcp://*:5556
//  Publishes random weather updates
//
//  Olivier Chamoux <olivier.chamoux@fr.thalesgroup.com>
//
#include <zmq.hpp>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <iostream>

#define within(num) (int) ((float) num * random () / (RAND_MAX + 1.0))

int main () {

    //  Prepare our context and publisher
    zmq::context_t context( 4 );
    zmq::socket_t publisher( context, ZMQ_PUB );
    publisher.bind( "tcp://*:5556" );
    //publisher.bind( "ipc://weather.ipc" );

    //  Initialize random number generator
    srandom ((unsigned) time (NULL));
    while (1) {

        int zipcode, temperature, relhumidity;

        //  Get values that will fool the boss
        zipcode     = within (100000);
        temperature = within (215) - 80;
        relhumidity = within (50) + 10;

        //  Send message to all subscribers
        zmq::message_t message( 20 );
        snprintf ((char *) message.data(), 20, "%05d %d %d", zipcode, temperature, relhumidity);
        bool result = publisher.send( message );
        if( !result )
            std::cout << "SendErr" << std::endl;

        sleep(1);
    }
    return 0;
}