std::weak_ptr::operator=
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                    | weak_ptr& operator=( const weak_ptr& r ); | (1) | (since C++11) | 
| template< class Y >  weak_ptr& operator=( const weak_ptr<Y>& r ); | (2) | (since C++11) | 
| template< class Y >  weak_ptr& operator=( const shared_ptr<Y>& r ); | (3) | (since C++11) | 
| weak_ptr& operator=( weak_ptr&& r ); | (4) | (since C++14) | 
| template< class Y >  weak_ptr& operator=( weak_ptr<Y>&& r ); | (5) | (since C++14) | 
Replaces the managed object with the one managed by r. The object is shared with r. If r manages no object, *this manages no object too. 
1-3) Equivalent to std::weak_ptr<T>(r).swap(*this).
4,5) Equivalent to std::weak_ptr<T>(std::move(r)).swap(*this).
Parameters
| r | - | smart pointer to share an object with | 
Return value
*this
Exceptions
noexcept specification:  
noexcept
  Notes
The implementation may meet the requirements without creating a temporary weak_ptr object.
See also
| creates a new weak_ptr(public member function) | |
| swaps the managed objects (public member function) |