C++ semaphore, condition variable mutex based.

Semaphore.h

struct Semaphore
{
    std::atomic_int count = 0;
    std::condition_variable cond_var;

    std::mutex mutex;

    void wait() {
        std::unique_lock<std::mutex> lock(mutex);
        while (!count)
        {
            cond_var.wait(lock);
        }
        count--;
    }

    void notify() {
        ++count;
        cond_var.notify_one();
    }
};