20 General utilities library [utilities]

20.8 Smart pointers [smartptr]

20.8.2 Shared-ownership pointers [util.smartptr]

20.8.2.3 Class template weak_ptr [util.smartptr.weak]

20.8.2.3.6 weak_ptr specialized algorithms [util.smartptr.weak.spec]

template<class T> void swap(weak_ptr<T>& a, weak_ptr<T>& b) noexcept;

Effects: Equivalent to a.swap(b).