std::future_status(3)

NAME
std::future_status - std::future_status

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

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