[zeromq-dev] CZMQ question re: use of zpoller

[Johnny Depp]

Hi Y'alls!

I have a problem that drives me nuts regarding CZMQ use of zpoller. First let me explain the environment: CZMQ version 4.2.1, ZMQ version 5.2.3, Centos 7, GCC version 4.8.5.

I am trying to use a client to push messages to a server. The client and the server at this point are pairs, but in the future, there will be a server and multiple clients.

I have the following C client:


int main() {
    zsys_debug("Sending...");

    zsock_t *client = zsock_new_push ("@tcp://127.0.0.1:9000");
    assert (client);

    char *string = NULL;

    int i = 0;
    for (i = 0; i < 100; i++) {
        string = zsys_sprintf ("%02d %s %s %s!", i, "Kilroy", "was", "here");
        zstr_send(client, string);
        zsys_debug("Sent: %s", string);
        free(string);
    }
    sleep(3);
    zsock_destroy (&client);

    zsys_debug("Done!'");

    return 0;
}

And I have the following C server running on a thread:

void *server(void *args) {

    zsock_t *my_server = zsock_new_pull(">tcp://127.0.0.1:9000");
    assert (my_server);

    // Set up poller
    zpoller_t *poller = zpoller_new (my_server, NULL);
    assert (poller);

    while(!zsys_interrupted) {
        zsock_t *which = (zsock_t *) zpoller_wait (poller, -1);

        if (which != NULL) {
            char *message = zstr_recv (which);
            zsys_debug("Message: %s", message);
            zstr_free (&message);
        } /*else {
            zsys_debug("nothing\n");
        }*/
    }

    zpoller_remove(poller, &my_server);
    zpoller_destroy (&poller);
    zsock_destroy (&my_server);
    pthread_exit(NULL);
}

My problem is this: When I use this code in two separate simple applications, the above code works. However, when I move the server into a larger application with multiple threads, it is starting to behave randomly: it works in some cases, but it mostly doesn't. The poller does detect anything on wait.

I am looking at this for over a week now and I cannot understand why. Can somebody please tell me what should I look for? Maybe I should use another approach?

Thank you,

Johnny
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.zeromq.org/pipermail/zeromq-dev/attachments/20200421/41317000/attachment.htm>