Zmq zmq_proxy / zmq_proxy_steerable无效

Question

我正在使用zmq_proxy进行xsub / xpub转发。但是，我经历了很多苦苦挣扎，仍然设法让它发挥作用。以下是我的代码：

#include <stdio.h>

#include "czmq.h"

//  The subscriber thread requests messages starting with
//  A and B, then reads and counts incoming messages.

static void
subscriber_thread(void *args, zctx_t *ctx, void *pipe)
{
    //  Subscribe to "A" and "B"
    void *subscriber = zsocket_new(ctx, ZMQ_SUB);
    zsocket_connect(subscriber, "tcp://localhost:6001");
    zsocket_set_subscribe(subscriber, "A");
    zsocket_set_subscribe(subscriber, "B");

    int count = 0;
    printf("sub sstarts..\n");
    while (count < 5) {
        char *string = zstr_recv(subscriber);
        printf("sub %s\n", string);
        if (!string)
            break;              //  Interrupted
        free(string);
        count++;
    }
    zsocket_destroy(ctx, subscriber);
}

//  The publisher sends random messages starting with A-J:

static void
publisher_thread(void *args, zctx_t *ctx, void *pipe)
{

    void *publisher = zsocket_new(ctx, ZMQ_PUB);
    zsocket_bind(publisher, "tcp://*:6000");

    printf("pub sstarts..\n");
    while (!zctx_interrupted) {
        char string[10];
        printf("pub %s\n", string);
        sprintf(string, "%c-%05d", randof(10) + 'A', randof(100000));
        if (zstr_send(publisher, string) == -1)
            break;              //  Interrupted
        zclock_sleep(100);     //  Wait for 1/10th second
    }
}

//  The listener receives all messages flowing through the proxy, on its
//  pipe. In CZMQ, the pipe is a pair of ZMQ_PAIR sockets that connect
//  attached child threads. In other languages your mileage may vary:

static void
listener_thread(void *args, zctx_t *ctx, void *pipe)
{
    //  Print everything that arrives on pipe
    while (true) {
        zframe_t *frame = zframe_recv(pipe);
        if (!frame)
            break;              //  Interrupted
        zframe_print(frame, NULL);
        zframe_destroy(&frame);
    }
}

//  The main task starts the subscriber and publisher, and then sets
//  itself up as a listening proxy. The listener runs as a child thread:

int main(void)
{
    //  Start child threads
    zctx_t *ctx = zctx_new();
    zthread_fork(ctx, publisher_thread, NULL);
    zthread_fork(ctx, subscriber_thread, NULL);

    zclock_sleep(1000);
    printf("main start\n");

    void *subscriber = zsocket_new(ctx, ZMQ_XSUB);
    zsocket_connect(subscriber, "tcp://localhost:6000");
    void *publisher = zsocket_new(ctx, ZMQ_XPUB);
    zsocket_bind(publisher, "tcp://*:6001");
    void *listener = zthread_fork(ctx, listener_thread, NULL);
    zmq_proxy_steerable(subscriber, publisher, listener, listener);

    puts(" interrupted");
    //  Tell attached threads to exit
    zctx_destroy(&ctx);
    return 0;
}

它基于zguild（link）中的示例。我期待在订阅者线程中打印一些内容，但是没有...