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class QueueEntry {
public:

    info_connection remove();

    void insert(int fd);

    size_t size() { return q.size(); }

private:
    std::mutex m;
    std::condition_variable w, r;
    std::deque<info_conn> q;
};

info_connection QueueEntry::remove(){
    std::unique_lock<std::mutex> lck(m);
    r.wait(lck, [this]() { return q.size() > 0; });
    auto i = std::move(q.front());
    q.pop_front();
    w.notify_one();
    return i;
}

void QueueEntry::insert(int fd){
    std::unique_lock<std::mutex> locker(m);
    w.wait(locker, [this]() { return q.size() < MAX_QUEUE_SIZE; });
    info_connection i { fd, std::chrono::system_clock::now() };
    q.push_back(i);
    r.notify_one();
}

class QueueEntry {
public:

    info_connection remove();

    void insert(int fd);

    size_t size() const { return q.size(); }

private:
    std::mutex m;
    std::condition_variable w, r;
    std::deque<info_conn> q;
};

info_connection QueueEntry::remove(){
    std::unique_lock<std::mutex> lck(m);
    r.wait(lck, [this]() { return q.size() > 0; });
    auto i = std::move(q.front());
    q.pop_front();
    w.notify_one();
    return i;
}

void QueueEntry::insert(int fd){
    std::unique_lock<std::mutex> locker(m);
    w.wait(locker, [this]() { return q.size() < MAX_QUEUE_SIZE; });
    info_connection i { fd, std::chrono::system_clock::now() };
    q.push_back(i);
    r.notify_one();
}

There's a lot of identical code shared between your queues, which is an indication to encapsulate them. Since they are stateful a class is appropriate here.

There's a lot of identical code shared between your queues, which is an indication to encapsulate them. Since they're stateful, a class is appropriate.

class QueuesManager {
    ...
    std::array<QueueEntry, 4> qs;
};

void QueuesManager::insert(int num, int fd) {
    if (num < 0 || num >= qs.size()) {
        throw std::runtime_error("fd out of buonds " + std::to_string(fd));
    }
    QueueEntry &q = qs[fd];
    q.insert(fd);
    printQueues(true);
}

void QueuesManager::remove(void) {
    while (true) {
        printQueues(false);
        for(auto &q : qs){
            if(q.size() > 0){
                info_conn ic = q.remove();
                break;
            }
        }
    }
}

class QueuesManager {
    ...
    std::array<QueueEntry, 4> qs;
};

void QueuesManager::insert(int num, int fd) {
    QueueEntry &q = qs.at(num);
    q.insert(fd);
    printQueues(true);
}

void QueuesManager::remove(void) {
    while (true) {
        printQueues(false);
        for(auto &q : qs){
            if(q.size() > 0){
                info_conn ic = q.remove();
                break;
            }
        }
    }
}