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std::experimental::future::future(3) C++ Standard Libary std::experimental::future::future(3)

NAME

std::experimental::future::future - std::experimental::future::future

Synopsis


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) (4)
noexcept;


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 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 future object.


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 constructs an empty
unclear with an invalid future future

See also


constructor constructs the future object
(public member function of std::future<T>)

2022.07.31 http://cppreference.com