boost/fusion/support/unused.hpp
/*=============================================================================
Copyright (c) 2001-2011 Joel de Guzman
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)
==============================================================================*/
#if !defined(BOOST_FUSION_SUPPORT_UNUSED_20070305_1038)
#define BOOST_FUSION_SUPPORT_UNUSED_20070305_1038
#include <iosfwd>
#include <boost/config.hpp>
#if defined(BOOST_MSVC)
# pragma warning(push)
# pragma warning(disable: 4522) // multiple assignment operators specified warning
#endif
#define BOOST_FUSION_UNUSED_HAS_IO
namespace boost { namespace fusion
{
struct unused_type
{
unused_type()
{
}
template <typename T>
unused_type(T const&)
{
}
template <typename T>
unused_type const&
operator=(T const&) const
{
return *this;
}
template <typename T>
unused_type&
operator=(T const&)
{
return *this;
}
unused_type const&
operator=(unused_type const&) const
{
return *this;
}
unused_type&
operator=(unused_type const&)
{
return *this;
}
};
unused_type const unused = unused_type();
namespace detail
{
struct unused_only
{
unused_only(unused_type const&) {}
};
}
inline std::ostream& operator<<(std::ostream& out, detail::unused_only const&)
{
return out;
}
inline std::istream& operator>>(std::istream& in, unused_type&)
{
return in;
}
}}
#if defined(BOOST_MSVC)
# pragma warning(pop)
#endif
#endif