boost::openmethod::virtual_ptr<SmartPtr, Registry>::virtual_ptr

Construct from a (const) smart pointer to a derived class

Synopsis

Declared in <boost/openmethod/core.hpp>

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

Description

Set the object pointer with a copy of other. Set the v‐table pointer according to the dynamic type of *other.

Examples

Constructing from a std::shared_ptr:

const std::shared_ptr<Dog> snoopy = std::make_shared<Dog>();
virtual_ptr<std::shared_ptr<Animal>> p = snoopy;

BOOST_TEST(p.get() == snoopy.get());
BOOST_TEST(p.vptr() == default_registry::static_vptr<Dog>);

A move‐only smart pointer cannot be copied from. Use the move constructor instead:

static_assert(
    std::is_constructible_v<
        unique_virtual_ptr<Animal>, const std::unique_ptr<Dog>&> ==
    false);

Requirements

  • SmartPtr and Other must be instantiated from the same template ‐ e.g. both std::shared_ptr or both std::unique_ptr.

  • Other must be a smart pointer to a polymorphic class derived from element_type.

  • SmartPtr must be constructible from const Other&.

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