Weather update server in C

//
// Weather update server
// Binds PUB socket to tcp://*:5556
// Publishes random weather updates
//
#include "zhelpers.h"

int main (void)
{
// Prepare our context and publisher
void *context = zmq_ctx_new ();
void *publisher = zmq_socket (context, ZMQ_PUB);
int rc = zmq_bind (publisher, "tcp://*:5556");
assert (rc == 0);
rc = zmq_bind (publisher, "ipc://weather.ipc");
assert (rc == 0);

// Initialize random number generator
srandom ((unsigned) time (NULL));
while (true) {
// Get values that will fool the boss
int zipcode, temperature, relhumidity;
zipcode = randof (100000);
temperature = randof (215) - 80;
relhumidity = randof (50) + 10;

// Send message to all subscribers
char update [20];
sprintf (update, "%05d %d %d", zipcode, temperature, relhumidity);
s_send (publisher, update);
}
zmq_close (publisher);
zmq_ctx_destroy (context);
return 0;
}