1 //
2 // placeholders.hpp
3 // ~~~~~~~~~~~~~~~~
4 //
5 // Copyright (c) 2003-2021 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::async_connect.
45 unspecified iterator;
46 
47 /// An argument placeholder, for use with boost::bind(), that corresponds to
48 /// the results argument of a handler for asynchronous functions such as
49 /// boost::asio::basic_resolver::async_resolve.
50 unspecified results;
51 
52 /// An argument placeholder, for use with boost::bind(), that corresponds to
53 /// the results argument of a handler for asynchronous functions such as
54 /// boost::asio::async_connect.
55 unspecified endpoint;
56 
57 /// An argument placeholder, for use with boost::bind(), that corresponds to
58 /// the signal_number argument of a handler for asynchronous functions such as
59 /// boost::asio::signal_set::async_wait.
60 unspecified signal_number;
61 
62 #elif defined(BOOST_ASIO_HAS_BOOST_BIND)
63 # if defined(__BORLANDC__) || defined(__GNUC__)
64 
65 inline boost::arg<1> error()
66 {
67   return boost::arg<1>();
68 }
69 
70 inline boost::arg<2> bytes_transferred()
71 {
72   return boost::arg<2>();
73 }
74 
75 inline boost::arg<2> iterator()
76 {
77   return boost::arg<2>();
78 }
79 
80 inline boost::arg<2> results()
81 {
82   return boost::arg<2>();
83 }
84 
85 inline boost::arg<2> endpoint()
86 {
87   return boost::arg<2>();
88 }
89 
90 inline boost::arg<2> signal_number()
91 {
92   return boost::arg<2>();
93 }
94 
95 # else
96 
97 namespace detail
98 {
99   template <int Number>
100   struct placeholder
101   {
102     static boost::arg<Number>& get()
103     {
104       static boost::arg<Number> result;
105       return result;
106     }
107   };
108 }
109 
110 #  if defined(BOOST_ASIO_MSVC) && (BOOST_ASIO_MSVC < 1400)
111 
112 static boost::arg<1>& error
113   = boost::asio::placeholders::detail::placeholder<1>::get();
114 static boost::arg<2>& bytes_transferred
115   = boost::asio::placeholders::detail::placeholder<2>::get();
116 static boost::arg<2>& iterator
117   = boost::asio::placeholders::detail::placeholder<2>::get();
118 static boost::arg<2>& results
119   = boost::asio::placeholders::detail::placeholder<2>::get();
120 static boost::arg<2>& endpoint
121   = boost::asio::placeholders::detail::placeholder<2>::get();
122 static boost::arg<2>& signal_number
123   = boost::asio::placeholders::detail::placeholder<2>::get();
124 
125 #  else
126 
127 namespace
128 {
129   boost::arg<1>& error
130     = boost::asio::placeholders::detail::placeholder<1>::get();
131   boost::arg<2>& bytes_transferred
132     = boost::asio::placeholders::detail::placeholder<2>::get();
133   boost::arg<2>& iterator
134     = boost::asio::placeholders::detail::placeholder<2>::get();
135   boost::arg<2>& results
136     = boost::asio::placeholders::detail::placeholder<2>::get();
137   boost::arg<2>& endpoint
138     = boost::asio::placeholders::detail::placeholder<2>::get();
139   boost::arg<2>& signal_number
140     = boost::asio::placeholders::detail::placeholder<2>::get();
141 } // namespace
142 
143 #  endif
144 # endif
145 #endif
146 
147 } // namespace placeholders
148 } // namespace asio
149 } // namespace boost
150 
151 #include <boost/asio/detail/pop_options.hpp>
152 
153 #endif // BOOST_ASIO_PLACEHOLDERS_HPP
154