deduction guides for std::weak_ptr

< cpp‎ | memory‎ | weak ptr
Dynamic memory management
Uninitialized storage
Garbage collection support
C Library
Low level memory management
Defined in header <memory>
template<class T>
weak_ptr(std::shared_ptr<T>) -> weak_ptr<T>;
(since C++17)

One deduction guide is provided for std::weak_ptr to account for the edge case missed by the implicit deduction guides.


#include <memory>
int main()
    auto p = std::make_shared<int>(42);
    std::weak_ptr w{p};    // explicit deduction guide is used in this case