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1 | // |
2 | // handler_type.hpp | |
3 | // ~~~~~~~~~~~~~~~~ | |
4 | // | |
11fdf7f2 | 5 | // Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com) |
b32b8144 FG |
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_HANDLER_TYPE_HPP | |
12 | #define BOOST_ASIO_HANDLER_TYPE_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 | #include <boost/asio/detail/type_traits.hpp> | |
20 | ||
21 | #include <boost/asio/detail/push_options.hpp> | |
22 | ||
23 | namespace boost { | |
24 | namespace asio { | |
25 | ||
26 | /// (Deprecated: Use two-parameter version of async_result.) Default handler | |
27 | /// type traits provided for all completion token types. | |
28 | /** | |
29 | * The handler_type traits class is used for determining the concrete handler | |
30 | * type to be used for an asynchronous operation. It allows the handler type to | |
31 | * be determined at the point where the specific completion handler signature | |
32 | * is known. | |
33 | * | |
34 | * This template may be specialised for user-defined completion token types. | |
35 | */ | |
36 | template <typename CompletionToken, typename Signature, typename = void> | |
37 | struct handler_type | |
38 | { | |
39 | /// The handler type for the specific signature. | |
40 | typedef typename conditional< | |
41 | is_same<CompletionToken, typename decay<CompletionToken>::type>::value, | |
42 | decay<CompletionToken>, | |
43 | handler_type<typename decay<CompletionToken>::type, Signature> | |
44 | >::type::type type; | |
45 | }; | |
46 | ||
47 | } // namespace asio | |
48 | } // namespace boost | |
49 | ||
50 | #include <boost/asio/detail/pop_options.hpp> | |
51 | ||
52 | #endif // BOOST_ASIO_HANDLER_TYPE_HPP |