boost/type_erasure/is_empty.hpp

0001 // Boost.TypeErasure library
0002 //
0003 // Copyright 2012 Steven Watanabe
0004 //
0005 // Distributed under the Boost Software License Version 1.0. (See
0006 // accompanying file LICENSE_1_0.txt or copy at
0007 // http://www.boost.org/LICENSE_1_0.txt)
0008 //
0009 // $Id$
0010
0011 #ifndef BOOST_TYPE_ERASURE_IS_EMPTY_HPP_INCLUDED
0012 #define BOOST_TYPE_ERASURE_IS_EMPTY_HPP_INCLUDED
0013
0014 #include <boost/type_erasure/detail/access.hpp>
0015
0016 namespace boost {
0017 namespace type_erasure {
0018
0019 /** Returns true for an empty @ref any. */
0020 template<class T>
0021 bool is_empty(const T& arg) {
0022     return ::boost::type_erasure::detail::access::data(arg).data == 0;
0023 }
0024
0025 }
0026 }
0027
0028 #endif