77 lines
1.6 KiB
C++
77 lines
1.6 KiB
C++
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#ifndef BOOST_MPL_VOID_HPP_INCLUDED
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#define BOOST_MPL_VOID_HPP_INCLUDED
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// Copyright Aleksey Gurtovoy 2001-2004
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//
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// See http://www.boost.org/libs/mpl for documentation.
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// $Id$
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// $Date$
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// $Revision$
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#include <boost/mpl/void_fwd.hpp>
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#include <boost/mpl/bool.hpp>
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#include <boost/mpl/aux_/na_spec.hpp>
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#include <boost/mpl/aux_/config/msvc.hpp>
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#include <boost/mpl/aux_/config/workaround.hpp>
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BOOST_MPL_AUX_ADL_BARRIER_NAMESPACE_OPEN
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// [JDG Feb-4-2003] made void_ a complete type to allow it to be
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// instantiated so that it can be passed in as an object that can be
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// used to select an overloaded function. Possible use includes signaling
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// a zero arity functor evaluation call.
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struct void_ { typedef void_ type; };
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BOOST_MPL_AUX_ADL_BARRIER_NAMESPACE_CLOSE
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namespace boost { namespace mpl {
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template< typename T >
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struct is_void_
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: false_
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{
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#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
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using false_::value;
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#endif
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};
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template<>
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struct is_void_<void_>
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: true_
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{
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#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
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using true_::value;
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#endif
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};
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template< typename T >
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struct is_not_void_
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: true_
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{
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#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
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using true_::value;
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#endif
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};
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template<>
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struct is_not_void_<void_>
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: false_
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{
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#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
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using false_::value;
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#endif
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};
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BOOST_MPL_AUX_NA_SPEC(1, is_void_)
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BOOST_MPL_AUX_NA_SPEC(1, is_not_void_)
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}}
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#endif // BOOST_MPL_VOID_HPP_INCLUDED
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