std::experimental::atomic_weak_ptr<T>::atomic_weak_ptr
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                    < cpp | experimental | atomic weak ptr
                    
                                                            
                    |   constexpr atomic_weak_ptr() noexcept;  | 
(1) | |
|   constexpr atomic_weak_ptr( weak_ptr<T> desired ) noexcept;  | 
(2) | |
|   atomic_weak_ptr( const atomic_weak_ptr& ) = delete;  | 
(3) | |
Constructs a new atomic_weak_ptr object.
1) The default constructor initializes the object to an empty state.
2) Initializes the underlying 
weak_ptr<T> with desired. The initialization is not atomic.3) Atomic variables are not CopyConstructible.
Parameters
| desired | - | value to initialize with |