C++ barrier

barrier.cpp

#include <chrono>
#include <condition_variable>
#include <iostream>
#include <thread>

class Barrier {
   public:
    Barrier(uint32_t count) : threadCount(count), counter(0), waiting(0) {}

    void wait() {
        std::unique_lock<std::mutex> lk(guard);
        ++counter;
        ++waiting;
        condition.wait(lk, [&] { return counter == threadCount; });
        condition.notify_all();
        --waiting;
        if (waiting == 0) {
            counter = 0;
        }
        lk.unlock();
    }

   private:
    std::mutex guard;
    std::condition_variable condition;
    uint32_t counter;
    uint32_t threadCount;
    uint32_t waiting;
};

Barrier barrier(4);

void fun1() {
    std::this_thread::sleep_for(std::chrono::seconds(3));
    barrier.wait();
    std::cout << "fun1 awake\n" << std::endl;
}

void fun2() {
    barrier.wait();
    std::cout << "fun2 awake\n" << std::endl;
}

int main() {
    std::thread t1(fun1);
    std::thread t2(fun2);
    std::thread t4(fun1);
    std::thread t3(fun2);
    t1.join();
    t2.join();
    t3.join();
    t4.join();
}