std::enable_shared_from_this<T>::weak_from_this
Since C++17
std::weak_ptr<T> weak_from_this() noexcept; (1)
std::weak_ptr<T const> weak_from_this() const noexcept; (2)
Returns a std::weak_ptr<T> that tracks ownership of *this by all existing std::shared_ptr that refer to *this.
Notes
This is a copy of the private mutable weak_ptr member that is part of enable_shared_from_this.
Return value
std::weak_ptr<T> that shares ownership of *this with pre-existing std::shared_ptr