deductionguidesforstd::weak_ptr -
deductionguidesforstd::weak_ptr
Defined in header <memory>
template<class T> (since C++17)
weak_ptr(std::shared_ptr<T>) -> weak_ptr<T>;
One deduction guide is provided for std::weak_ptr to account for the edge
case
missed by the implicit deduction guides.
// Run this code
#include <memory>
int main()
{
auto p = std::make_shared<int>(42);
std::weak_ptr w{p}; // explicit deduction guide is used in this case
}