boost::openmethod::virtual_ptr::virtual_ptr

explicit
virtual_ptr(std::nullptr_t);

struct Animal { virtual ~Animal() { } }; // polymorphic
struct Dog : Animal {}; // polymorphic
BOOST_OPENMETHOD_CLASSES(Animal, Dog);
initialize();

virtual_ptr<Dog> p{nullptr};
BOOST_TEST(p.get() == nullptr);
BOOST_TEST(p.vptr() == nullptr);