#include <iostream>
#include <future>
#include <chrono>

int main()
{
    std::cout << "future status ready : " << static_cast<int>(std::future_status::ready) << '\n';
    std::cout << "future status deferred : " << static_cast<int>(std::future_status::deferred) << '\n';
    std::cout << "future status timeout : " << static_cast<int>(std::future_status::timeout) << '\n';
}
/* Output
future status ready : 0
future status deferred : 2
future status timeout : 1
*/