使用条件变量condition_variable实现超时功能

#include

#include

#include

#include

#include

#include

using namespace std::chrono_literals;

std::condition_variable cv;

std::mutex cv_m;

std::atomic<int> i{0};

void signals()

{

    std::this_thread::sleep_for(120ms);

    std::cerr << "Notifying...\n";

    cv.notify_all();

    i = 100;

}

void func() {

    std::thread t1(signals);

    t1.detach();

    std::unique_lock::mutex> lk(cv_m);

    auto now = std::chrono::system_clock::now();

    auto end = now + std::chrono::milliseconds(100); //结束时间

//    auto end = now + std::chrono::milliseconds(200); //结束时间

    if(cv.wait_until(lk, end, [](){return i == 100;})) {

        std::cerr << "Thread " << 1 << " finished waiting. i == " << i << '\n';

        return;

    }

    else{

        std::cerr << "Thread " << 1 << " timed out. i == " << i << '\n';

        return;

    }

}

int main()

{

    auto start = std::chrono::high_resolution_clock::now();

    func();

    auto stop = std::chrono::high_resolution_clock::now();

    std::cout << "interval " << (stop - start).count() << std::endl;

    return 0;

}