#include <condition_variable>
#include <mutex>
#include <thread>
#include <iostream>

std::mutex mtx;
std::condition_variable cv;
bool ready = false;

void worker() {
    std::unique_lock<std::mutex> lock(mtx);
    cv.wait(lock, []{ return ready; }); // Ждём сигнала
    
    std::cout << "Worker started!\n";
}

int main() {
    std::thread t(worker);
    
    std::this_thread::sleep_for(std::chrono::seconds(1));
    
    {
        std::lock_guard<std::mutex> lock(mtx);
        ready = true;
    }
    cv.notify_one(); // Будим поток
    
    t.join();
    return 0;
}