1 /*=============================================================================
2     Copyright (c) 2001-2011 Joel de Guzman
3 
4     Distributed under the Boost Software License, Version 1.0. (See accompanying
5     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6 ==============================================================================*/
7 #if !defined(BOOST_FUSION_SUPPORT_UNUSED_20070305_1038)
8 #define BOOST_FUSION_SUPPORT_UNUSED_20070305_1038
9 
10 #include <boost/fusion/support/config.hpp>
11 #include <iosfwd>
12 
13 #include <boost/config.hpp>
14 #if defined(BOOST_MSVC)
15 # pragma warning(push)
16 # pragma warning(disable: 4522) // multiple assignment operators specified warning
17 #endif
18 
19 #define BOOST_FUSION_UNUSED_HAS_IO
20 
21 namespace boost { namespace fusion
22 {
23     struct unused_type
24     {
25         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
unused_typeboost::fusion::unused_type26         unused_type() BOOST_NOEXCEPT
27         {
28         }
29 
30         template <typename T>
31         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
unused_typeboost::fusion::unused_type32         unused_type(T const&) BOOST_NOEXCEPT
33         {
34         }
35 
36         template <typename T>
37         BOOST_FUSION_CONSTEXPR_THIS BOOST_FUSION_GPU_ENABLED
38         unused_type const&
operator =boost::fusion::unused_type39         operator=(T const&) const BOOST_NOEXCEPT
40         {
41             return *this;
42         }
43 
44         template <typename T>
45         BOOST_CXX14_CONSTEXPR BOOST_FUSION_GPU_ENABLED
46         unused_type&
operator =boost::fusion::unused_type47         operator=(T const&) BOOST_NOEXCEPT
48         {
49             return *this;
50         }
51 
52         BOOST_FUSION_CONSTEXPR_THIS BOOST_FUSION_GPU_ENABLED
53         unused_type const&
operator =boost::fusion::unused_type54         operator=(unused_type const&) const BOOST_NOEXCEPT
55         {
56             return *this;
57         }
58 
59         BOOST_CXX14_CONSTEXPR BOOST_FUSION_GPU_ENABLED
60         unused_type&
operator =boost::fusion::unused_type61         operator=(unused_type const&) BOOST_NOEXCEPT
62         {
63             return *this;
64         }
65     };
66 
67     BOOST_CONSTEXPR_OR_CONST unused_type unused = unused_type();
68 
69     namespace detail
70     {
71         struct unused_only
72         {
73             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
unused_onlyboost::fusion::detail::unused_only74             unused_only(unused_type const&) BOOST_NOEXCEPT {}
75         };
76     }
77 
78     BOOST_CONSTEXPR
operator <<(std::ostream & out,detail::unused_only const &)79     inline std::ostream& operator<<(std::ostream& out, detail::unused_only const&) BOOST_NOEXCEPT
80     {
81         return out;
82     }
83 
84     BOOST_CONSTEXPR
operator >>(std::istream & in,unused_type &)85     inline std::istream& operator>>(std::istream& in, unused_type&) BOOST_NOEXCEPT
86     {
87         return in;
88     }
89 }}
90 
91 #if defined(BOOST_MSVC)
92 # pragma warning(pop)
93 #endif
94 
95 #endif
96