std::experimental::future<T>::operator=

std::experimental::future<T>& operator=( std::experimental::future<T>&& other ) noexcept;	(1)
std::experimental::future<T>& operator=( const std::experimental::future<T>& other ) = delete;	(2)

賦值另一個 future 物件的內容。

1) 釋放任何共享狀態，並將 other 的內容移動賦值給 *this。賦值後，other.valid() == false，且 this->valid() 將產生與賦值前 other.valid() 相同的值。

2) std::experimental::future 不可複製賦值 (CopyAssignable)。

其他 - 一個 std::experimental::future，它將把狀態轉移給 *this

*this

std::future 擴充套件
experimental::future
experimental::shared_future
experimental::when_all
experimental::when_any
experimental::make_ready_future
experimental::make_exceptional_future
鎖存器和屏障
experimental::latch
experimental::barrier
experimental::flex_barrier
原子智慧指標
experimental::atomic_shared_ptr
experimental::atomic_weak_ptr