std::experimental::future<T>::future
From cppreference.com
< cpp | experimental | future
| future() noexcept; |
(1) | |
| future( std::experimental::future<T>&& f ) noexcept; |
(2) | |
| future( const std::experimental::future<T>& ) = delete; |
(3) | |
| future( std::experimental::future<std::experimental::future<T>> && other ) noexcept; |
(4) | |
1) Default constructor. Constructs an empty
future object that does not refer to a shared state.2) Constructs a
future object, transferring the shared state held by f, if any. After construction, f.valid() is false.3) Copy constructor is deleted.
future cannot be copied.4) Unwrapping constructor. Constructs a
future object from the shared state referred to by other, if any. If other.valid() == false prior to this call, the constructed future object is empty. Otherwise, the resulting 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
futureobject. - 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
futureobject.
After this constructor returns, valid() is equal to the value of other.valid() prior to this call, and other.valid() == false.
Parameters
| f | - | another future object to initialize with |
| other | - | a std::experimental::future object to unwrap
|
Example
| This section is incomplete Reason: no example |
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
|
See also
| constructs the future object (public member function of std::future<T>) |