boost::openmethod::virtual_ptr::virtual_ptr

virtual_ptr() = default;

template<class Other>
requires std::is_constructible_v<
            Class*, typename virtual_ptr<Other, Registry>::element_type*>
virtual_ptr(virtual_ptr<Other, Registry> const& other);

explicit
virtual_ptr(std::nullptr_t);

template<class Other>
requires IsPolymorphic<Other, Registry> &&
            std::is_constructible_v<Class*, Other*>
virtual_ptr(Other& other);

template<class Other>
requires IsPolymorphic<Class, Registry> &&
            std::is_constructible_v<Class*, Other*>
virtual_ptr(Other* other);