# std::experimental::future

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< cpp‎ | experimental

Defined in header `<experimental/future>` |  |
template< class T > class future; | (1) | (concurrency TS)
template< class T > class future<T&>; | (2) | (concurrency TS)
template<> class future<void>; | (3) | (concurrency TS)

The class template `std::experimental::future` extends std::future with the following operations:

- an unwrapping constructor from `future<future<T>>`;
- a member function `is_ready` to query whether the associated shared state is ready; and
- a member function `then` to attach a continuation to the future.

However, there is no interoperation between `std::experimental::future` and std::future.

### Member functions

(constructor) | construct a `future` object (public member function)
is_ready | checks if the shared state is ready (public member function)
then | attaches a continuation to a future (public member function)
operator= | moves the future object (public member function)

## Members identical to std::future

### Member functions

Note that `share()` returns a std::experimental::shared_future<T>. The behavior is otherwise identical.

(destructor) | destructs the future object (public member function of `std::future<T>`)
share | transfers the shared state from `*this` to a `shared_future` and returns it (public member function of `std::future<T>`)

##### Getting the result

get | returns the result (public member function of `std::future<T>`)

##### State

valid | checks if the future has a shared state (public member function of `std::future<T>`)
wait | waits for the result to become available (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::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>`)

### Example

| This section is incomplete Reason: no example

### See also

shared_future (concurrency TS) | A version of std::shared_future enhanced with continuations and other features (class template)

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