forked from boostorg/mpl
54 lines
1.5 KiB
C++
54 lines
1.5 KiB
C++
//-----------------------------------------------------------------------------
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// boost mpl/void.hpp header file
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// See http://www.boost.org for updates, documentation, and revision history.
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//-----------------------------------------------------------------------------
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//
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// Copyright (c) 2001-02
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// Peter Dimov, Aleksey Gurtovoy
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//
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// Permission to use, copy, modify, distribute and sell this software
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// and its documentation for any purpose is hereby granted without fee,
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// provided that the above copyright notice appears in all copies and
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// that both the copyright notice and this permission notice appear in
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// supporting documentation. No representations are made about the
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// suitability of this software for any purpose. It is provided "as is"
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// without express or implied warranty.
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#ifndef BOOST_MPL_VOID_HPP_INCLUDED
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#define BOOST_MPL_VOID_HPP_INCLUDED
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#include "boost/mpl/bool.hpp"
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#include "boost/config.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_ {};
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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 defined(BOOST_MSVC) && 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 defined(BOOST_MSVC) && 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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