zstream.c

#include <zmq.h>
#include <czmq.h>
#include "include/dbg.h"

#define DEBUG 1

int
main (void)
{
    void *ctx = zmq_ctx_new ();

    void *stream_in = zmq_socket (ctx, ZMQ_STREAM);
    assert (stream_in);
    int rc = zmq_bind (stream_in, "tcp://*:9999");
    assert (rc == 0);

    while (1) {

        /* NOTE - using zmq_recv from libzmq directly, so that I can read
         * a buffer of a specified length from the socket, since ZMQ_STREAM
         * is a streaming socket type and does not provide message delimiters
         */
        char buf[1024];
        size_t buf_size = 1024;
        buf_size = zmq_recv (stream_in, buf, buf_size, 0);

        /* The first message we receive from the socket should be the zmq id
         * of the connected client.  Print it out to verify */
        int i;
        for (i=0; i<buf_size; i++) {
            printf ("%02X", (unsigned char) buf [i]);
        }
        printf ("\n");

        /* The MORE flag should be sent, as each message received from a
         * ZMQ_STREAM socket should be a two part multi part message - the
         * first part being the id, the second part being the message itself */
        int64_t more;
        size_t more_size = sizeof (more);
        zmq_getsockopt (stream_in, ZMQ_RCVMORE, &more, &more_size);

        /* more SHOULD always be true, to my understanding */
        if (more) {
            buf_size = zmq_recv (stream_in, buf, 1024, 0);
            for (i=0; i<buf_size; i++) {
                printf ("%c", buf [i]);
            }
            printf ("\n");
        }

        /* if we're here something weird happened or our understanding
         * of ZMQ_STREAM is wrong. */
        else {
            log_failed ("Something really bad happened - more flag wasn't set.");
        }
    }

    return EXIT_SUCCESS;
}