src/thirdparty/boost_1_47_0/boost/mpl/void.hpp

   1
   2 #ifndef BOOST_MPL_VOID_HPP_INCLUDED
   3 #define BOOST_MPL_VOID_HPP_INCLUDED
   4
   5 // Copyright Aleksey Gurtovoy 2001-2004
   6 //
   7 // Distributed under the Boost Software License, Version 1.0.
   8 // (See accompanying file LICENSE_1_0.txt or copy at
   9 // http://www.boost.org/LICENSE_1_0.txt)
  10 //
  11 // See http://www.boost.org/libs/mpl for documentation.
  12
  13 // $Id: void.hpp 49267 2008-10-11 06:19:02Z agurtovoy $
  14 // $Date: 2008-10-11 02:19:02 -0400 (Sat, 11 Oct 2008) $
  15 // $Revision: 49267 $
  16
  17 #include <boost/mpl/void_fwd.hpp>
  18 #include <boost/mpl/bool.hpp>
  19 #include <boost/mpl/aux_/na_spec.hpp>
  20 #include <boost/mpl/aux_/config/msvc.hpp>
  21 #include <boost/mpl/aux_/config/workaround.hpp>
  22
  23 BOOST_MPL_AUX_ADL_BARRIER_NAMESPACE_OPEN
  24
  25 //  [JDG Feb-4-2003] made void_ a complete type to allow it to be
  26 //  instantiated so that it can be passed in as an object that can be
  27 //  used to select an overloaded function. Possible use includes signaling
  28 //  a zero arity functor evaluation call.
  29 struct void_ { typedef void_ type; };
  30
  31 BOOST_MPL_AUX_ADL_BARRIER_NAMESPACE_CLOSE
  32
  33 namespace boost { namespace mpl {
  34
  35 template< typename T >
  36 struct is_void_
  37     : false_
  38 {
  39 #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
  40     using false_::value;
  41 #endif
  42 };
  43
  44 template<>
  45 struct is_void_<void_>
  46     : true_
  47 {
  48 #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
  49     using true_::value;
  50 #endif
  51 };
  52
  53 template< typename T >
  54 struct is_not_void_
  55     : true_
  56 {
  57 #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
  58     using true_::value;
  59 #endif
  60 };
  61
  62 template<>
  63 struct is_not_void_<void_>
  64     : false_
  65 {
  66 #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
  67     using false_::value;
  68 #endif
  69 };
  70
  71 BOOST_MPL_AUX_NA_SPEC(1, is_void_)
  72 BOOST_MPL_AUX_NA_SPEC(1, is_not_void_)
  73
  74 }}
  75
  76 #endif // BOOST_MPL_VOID_HPP_INCLUDED