void loop(DB *db, void *socket) {
  void *raw = NULL;
  char *res = NULL;
  zmq_msg_t request;
  zmq_msg_t reply;
   size_t len = 0;

  while(!quit) {
    zmq_msg_init(&request);
    zmq_recv(socket, &request, 0);

    <process request>

    zmq_msg_close(&request);
    len = strlen(res) + 1;

    // Send reply back to client
    xsend(socket, len, res, 0);
    free(res);
  }
}