4 Copyright (c) 2003-2007 Fernando Luis Cacciola Carballal
5 Copyright (c) 2015 Andrzej Krzemienski
7 Distributed under the Boost Software License, Version 1.0.
8 (See accompanying file LICENSE_1_0.txt or copy at
9 http://www.boost.org/LICENSE_1_0.txt)
12 [section Header <boost/optional/optional_fwd.hpp>]
18 template <class T> class optional ;
20 template <class T> void swap ( optional<T>& , optional<T>& );
22 template <class T> struct optional_swap_should_use_default_constructor ;
27 This header only contains declarations.