libs/type_traits/doc/is_virtual_base_of.qbk
[/ Copyright 2009 John Maddock. Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt). ] [section:is_virtual_base_of is_virtual_base_of] template <class Base, class Derived> struct is_virtual_base_of : public __tof {}; __inherit If Base is a virtual base class of type Derived then inherits from __true_type, otherwise inherits from __false_type. Types `Base` and `Derived` must not be incomplete types. __std_ref 10. __header ` #include <boost/type_traits/is_virtual_base_of.hpp>` or ` #include <boost/type_traits.hpp>` __compat this trait also requires a working __is_base_of trait. __examples [:Given: ` class Base{}; class Derived : public virtual Base{};` ] [:`is_virtual_base_of<Base, Derived>` inherits from `__true_type`.] [:`is_virtual_base_of<Base, Derived>::type` is the type `__true_type`.] [:`is_virtual_base_of<Base, Derived>::value` is an integral constant expression that evaluates to /true/.] [:`is_virtual_base_of<Base, Derived>::value` is an integral constant expression that evaluates to /true/.] [:`is_virtual_base_of<T, U>::value_type` is the type `bool`.] [endsect]