Freelance server, Model Two in C

//
// Freelance server - Model 2
// Does some work, replies OK, with message sequencing
//
#include "czmq.h"

int main (int argc, char *argv [])
{
if (argc < 2) {
printf ("I: syntax: %s <endpoint>\n", argv [0]);
exit (EXIT_SUCCESS);
}
zctx_t *ctx = zctx_new ();
void *server = zsocket_new (ctx, ZMQ_REP);
zsocket_bind (server, argv [1]);

printf ("I: service is ready at %s\n", argv [1]);
while (true) {
zmsg_t *request = zmsg_recv (server);
if (!request)
break; // Interrupted
// Fail nastily if run against wrong client
assert (zmsg_size (request) == 2);

zframe_t *address = zmsg_pop (request);
zmsg_destroy (&request);

zmsg_t *reply = zmsg_new ();
zmsg_add (reply, address);
zmsg_addstr (reply, "OK");
zmsg_send (&reply, server);
}
if (zctx_interrupted)
printf ("W: interrupted\n");

zctx_destroy (&ctx);
return 0;
}