Listing 13 in C

void my_free (void *data, void *hint) {
free (data);
}
// Send message from buffer, which we allocate and ZeroMQ will free for us
zmq_msg_t message;
zmq_msg_init_data (&message, buffer, 1000, my_free, NULL);
zmq_msg_send (&message, socket, 0);