std::future_status

Defined in header `<future>`
enum class future_status { ready, timeout, deferred };		(since C++11)

Specifies state of a future as returned by wait_for and wait_until functions of std::future and std::shared_future.

Constant	Explanation
`deferred`	the shared state contains a deferred function, so the result will be computed only when explicitly requested
`ready`	the shared state is ready
`timeout`	the shared state did not become ready before specified timeout duration has passed

wait_for	waits for the result, returns if it is not available for the specified timeout duration (public member function of `std::future<T>`)
wait_for	waits for the result, returns if it is not available for the specified timeout duration (public member function of `std::shared_future<T>`)
wait_until	waits for the result, returns if it is not available until specified time point has been reached (public member function of `std::future<T>`)
wait_until	waits for the result, returns if it is not available until specified time point has been reached (public member function of `std::shared_future<T>`)