c++ - 获取 std::future::wait_for 的运行时间

Question

有没有一种简单的方法来获取 std::future<T>::wait_for 期间耗时？如果没有超时发生？我想实现这样的目标:

std::future<void> futureRet = std::async(std::launch::async, &Someone::doSomething, this);
futureRet.wait_for(std::chrono::seconds(30));

cout << "doSomething returned after <" << futureRet.getElapsedTime() << "> seconds.";

是否有一种“getElapsedTime()”函数，还是我必须自己计算耗时？

Answer 1

有一个简单的方法使用 <chrono> :

auto start = std::chrono::steady_clock::now();
std::future<void> futureRet = std::async(std::launch::async, &Someone::doSomething, this);
futureRet.wait_for(std::chrono::seconds(30));
auto end = std::chrono::steady_clock::now();
std::chrono::duration<double> elapsed_seconds = end - start;    
cout << "doSomething returned after <" << elapsed_seconds.count() << "> seconds.";