1 //
2 // placeholders.hpp
3 // ~~~~~~~~~~~~~~~~
4 //
5 // Copyright (c) 2003-2015 Christopher M. Kohlhoff (chris at kohlhoff dot com)
6 //
7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
9 //
10 
11 #ifndef BOOST_ASIO_PLACEHOLDERS_HPP
12 #define BOOST_ASIO_PLACEHOLDERS_HPP
13 
14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
15 # pragma once
16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
17 
18 #include <boost/asio/detail/config.hpp>
19 
20 #if defined(BOOST_ASIO_HAS_BOOST_BIND)
21 # include <boost/bind/arg.hpp>
22 #endif // defined(BOOST_ASIO_HAS_BOOST_BIND)
23 
24 #include <boost/asio/detail/push_options.hpp>
25 
26 namespace boost {
27 namespace asio {
28 namespace placeholders {
29 
30 #if defined(GENERATING_DOCUMENTATION)
31 
32 /// An argument placeholder, for use with boost::bind(), that corresponds to
33 /// the error argument of a handler for any of the asynchronous functions.
34 unspecified error;
35 
36 /// An argument placeholder, for use with boost::bind(), that corresponds to
37 /// the bytes_transferred argument of a handler for asynchronous functions such
38 /// as boost::asio::basic_stream_socket::async_write_some or
39 /// boost::asio::async_write.
40 unspecified bytes_transferred;
41 
42 /// An argument placeholder, for use with boost::bind(), that corresponds to
43 /// the iterator argument of a handler for asynchronous functions such as
44 /// boost::asio::basic_resolver::async_resolve.
45 unspecified iterator;
46 
47 /// An argument placeholder, for use with boost::bind(), that corresponds to
48 /// the signal_number argument of a handler for asynchronous functions such as
49 /// boost::asio::signal_set::async_wait.
50 unspecified signal_number;
51 
52 #elif defined(BOOST_ASIO_HAS_BOOST_BIND)
53 # if defined(__BORLANDC__) || defined(__GNUC__)
54 
55 inline boost::arg<1> error()
56 {
57   return boost::arg<1>();
58 }
59 
60 inline boost::arg<2> bytes_transferred()
61 {
62   return boost::arg<2>();
63 }
64 
65 inline boost::arg<2> iterator()
66 {
67   return boost::arg<2>();
68 }
69 
70 inline boost::arg<2> signal_number()
71 {
72   return boost::arg<2>();
73 }
74 
75 # else
76 
77 namespace detail
78 {
79   template <int Number>
80   struct placeholder
81   {
82     static boost::arg<Number>& get()
83     {
84       static boost::arg<Number> result;
85       return result;
86     }
87   };
88 }
89 
90 #  if defined(BOOST_ASIO_MSVC) && (BOOST_ASIO_MSVC < 1400)
91 
92 static boost::arg<1>& error
93   = boost::asio::placeholders::detail::placeholder<1>::get();
94 static boost::arg<2>& bytes_transferred
95   = boost::asio::placeholders::detail::placeholder<2>::get();
96 static boost::arg<2>& iterator
97   = boost::asio::placeholders::detail::placeholder<2>::get();
98 static boost::arg<2>& signal_number
99   = boost::asio::placeholders::detail::placeholder<2>::get();
100 
101 #  else
102 
103 namespace
104 {
105   boost::arg<1>& error
106     = boost::asio::placeholders::detail::placeholder<1>::get();
107   boost::arg<2>& bytes_transferred
108     = boost::asio::placeholders::detail::placeholder<2>::get();
109   boost::arg<2>& iterator
110     = boost::asio::placeholders::detail::placeholder<2>::get();
111   boost::arg<2>& signal_number
112     = boost::asio::placeholders::detail::placeholder<2>::get();
113 } // namespace
114 
115 #  endif
116 # endif
117 #endif
118 
119 } // namespace placeholders
120 } // namespace asio
121 } // namespace boost
122 
123 #include <boost/asio/detail/pop_options.hpp>
124 
125 #endif // BOOST_ASIO_PLACEHOLDERS_HPP
126