forked from boostorg/mpl
53 lines
1.2 KiB
C++
53 lines
1.2 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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// + file: boost/mpl/void.hpp
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// + last modified: 05/may/03
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// Copyright (c) 2001-03
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// Peter Dimov, Aleksey Gurtovoy
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// 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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#include "boost/mpl/void_fwd.hpp"
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#include "boost/mpl/bool.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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namespace boost {
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namespace mpl {
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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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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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} // namespace mpl
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} // namespace boost
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#endif // BOOST_MPL_VOID_HPP_INCLUDED
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