设置临时 std::future 的值

Question

I have a function which returns a std::pair<std::future<bool>,std::future_status> . In some cases I want future.get() to always return true and I was wondering if there was a legit way of doing it. Currently I am doing something horrendous:

std::future<bool> tmp = std::async(std::launch::async,[]()->bool{return true;}); 
return std::make_pair(std::move(tmp), std::future_status::ready); 

Does anybody know a better way of setting the value of tmp to true?

Answer 1

I'm not sure what effect you're trying to achieve, but you can use a std::promise to directly set the value of a std::future :

#include<future>

std::promise<bool> tmpPromise; //default construct promise

std::future<bool> tmp = tmpPromise.get_future(); //get future associated with promise

tmpPromise.set_value(true); //set future value

return std::make_pair(tmp, std::future_status::ready);