ZMQ guide is missing DEALER-DEALER example

[StephenApptronik]

In the ZMQ Guide here:
http://zguide.zeromq.org/php:chapter3#The-DEALER-to-DEALER-Combination
Quote: "We’ll see a worked example later. Let’s just say for now that DEALER to DEALER is one of the trickier patterns to get right, and happily it’s rare that we need it."

I cannot find a DEALER-DEALER example later. Given that it is "one of the trickier patterns to get right", I'd like to know how to deal with those tricks.

If the example does exist, it would be kind to update the docs to make the quote above be a hyperlink to that later example.

[StephenApptronik]

I did manage to get Google's AI to emit this code. The code looks right, but I don't have any way to vet it for any tricky corner cases it may be missing.

---

#include <zmq.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define PEER1_ADDRESS "tcp://*:5555"
#define PEER2_ADDRESS "tcp://localhost:5555"

void peer_function(int peer_id) {
    void *context = zmq_ctx_new();
    void *socket = zmq_socket(context, ZMQ_DEALER);

    // Set an identity for each peer
    char identity[10];
    sprintf(identity, "peer%d", peer_id);
    zmq_setsockopt(socket, ZMQ_IDENTITY, identity, strlen(identity));

    if (peer_id == 1) {
        zmq_bind(socket, PEER1_ADDRESS);
        printf("Peer 1 bound to %s\n", PEER1_ADDRESS);
    } else {
        zmq_connect(socket, PEER2_ADDRESS);
        printf("Peer 2 connected to %s\n", PEER2_ADDRESS);
    }

    // Main loop
    for(int i = 0; i < 5; i++) {
        if (peer_id == 1) { // Peer 1 sends messages
            char message[20];
            sprintf(message, "Hello from peer 1, %d", i);
            printf("Peer 1 sending: %s\n", message);
            zmq_msg_t zm_msg;
            zmq_msg_init_size(&zm_msg, strlen(message));
            memcpy(zmq_msg_data(&zm_msg), message, strlen(message));
            zmq_msg_send(&zm_msg, socket, 0);
            zmq_msg_close(&zm_msg);
            sleep(1);
        } else { // Peer 2 receives messages
            zmq_msg_t zm_msg;
            zmq_msg_init(&zm_msg);
            zmq_msg_recv(&zm_msg, socket, 0);
            char *received_message = (char *)zmq_msg_data(&zm_msg);
            printf("Peer 2 received: %s\n", received_message);
            zmq_msg_close(&zm_msg);
        }
    }

    zmq_close(socket);
    zmq_ctx_destroy(context);
}

int main() {
    pid_t pid = fork();
    if (pid == 0) {
        peer_function(1); // Peer 1
    } else if (pid > 0) {
        peer_function(2); // Peer 2
        wait(NULL);
    } else {
        perror("fork failed");
        return 1;
    }
    return 0;
}

[StephenApptronik]

I've just noticed that the above code does not check for errors from the send/recv functions. That should be added to an example.