| // |
| // handler_type.hpp |
| // ~~~~~~~~~~~~~~~~ |
| // |
| // Copyright (c) 2003-2016 Christopher M. Kohlhoff (chris at kohlhoff dot com) |
| // |
| // Distributed under the Boost Software License, Version 1.0. (See accompanying |
| // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| // |
| |
| #ifndef ASIO_HANDLER_TYPE_HPP |
| #define ASIO_HANDLER_TYPE_HPP |
| |
| #if defined(_MSC_VER) && (_MSC_VER >= 1200) |
| # pragma once |
| #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) |
| |
| #include "asio/detail/config.hpp" |
| #include "asio/detail/type_traits.hpp" |
| |
| #include "asio/detail/push_options.hpp" |
| |
| namespace asio { |
| |
| /// (Deprecated: Use two-parameter version of async_result.) Default handler |
| /// type traits provided for all completion token types. |
| /** |
| * The handler_type traits class is used for determining the concrete handler |
| * type to be used for an asynchronous operation. It allows the handler type to |
| * be determined at the point where the specific completion handler signature |
| * is known. |
| * |
| * This template may be specialised for user-defined completion token types. |
| */ |
| template <typename CompletionToken, typename Signature, typename = void> |
| struct handler_type |
| { |
| /// The handler type for the specific signature. |
| typedef typename conditional< |
| is_same<CompletionToken, typename decay<CompletionToken>::type>::value, |
| decay<CompletionToken>, |
| handler_type<typename decay<CompletionToken>::type, Signature> |
| >::type::type type; |
| }; |
| |
| } // namespace asio |
| |
| #include "asio/detail/pop_options.hpp" |
| |
| #endif // ASIO_HANDLER_TYPE_HPP |