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std::experimental::shared_future<T>::shared_future

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shared_future() noexcept;
(1)
shared_future( std::experimental::shared_future<T>&& f ) noexcept;
(2)
shared_future( const std::experimental::shared_future<T>& f );
(3)
shared_future( std::experimental::future<std::experimental::shared_future<T>> && other ) noexcept;
(4)
shared_future( std::experimental::future<T>&& f ) noexcept;
(5)
1) Default constructor. Constructs an empty shared_future object that does not refer to a shared state.
2) Constructs a shared_future object, transferring the shared state held by f, if any. After construction, f.valid() is false.
3) Constructs a shared future that refers to the same shared state as f, if any.
4) Unwrapping constructor. Constructs a shared_future object from the shared state referred to by other, if any. If other.valid() == false prior to this call, the constructed shared_future object is empty. Otherwise, the resulting shared_future object becomes ready when one of the following happens:
  • other and other.get() are both ready. The value or exception from other.get() is stored in the shared state associated with the resulting shared_future object.
  • other is ready, but other.get() is invalid. An exception of type std::future_error with an error condition of std::future_errc::broken_promise is stored in the shared state associated with the resulting shared_future object.
After this constructor returns, valid() is equal to the value of other.valid() prior to this call, and other.valid() == false.
5) Constructs a shared_future object, transferring the shared state held by f, if any. After construction, f.valid() is false.

Contents

[edit] Parameters

f - another future object to initialize with
other - a std::experimental::future object to unwrap

[edit] Example

[edit] Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 2697 Concurrency TS behavior of unwrapping constructor is unclear with an invalid future constructs an empty future

[edit] See also

constructs the future object
(public member function of std::shared_future<T>) [edit]