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- //
- // packaged_task.hpp
- // ~~~~~~~~~~~~~~~~~
- //
- // Copyright (c) 2003-2019 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_PACKAGED_TASK_HPP
- #define ASIO_PACKAGED_TASK_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/future.hpp"
-
- #if defined(ASIO_HAS_STD_FUTURE_CLASS) \
- || defined(GENERATING_DOCUMENTATION)
-
- #include "asio/async_result.hpp"
- #include "asio/detail/type_traits.hpp"
- #include "asio/detail/variadic_templates.hpp"
-
- #include "asio/detail/push_options.hpp"
-
- namespace asio {
-
- #if defined(ASIO_HAS_VARIADIC_TEMPLATES) \
- || defined(GENERATING_DOCUMENTATION)
-
- /// Partial specialisation of @c async_result for @c std::packaged_task.
- template <typename Result, typename... Args, typename Signature>
- class async_result<std::packaged_task<Result(Args...)>, Signature>
- {
- public:
- /// The packaged task is the concrete completion handler type.
- typedef std::packaged_task<Result(Args...)> completion_handler_type;
-
- /// The return type of the initiating function is the future obtained from
- /// the packaged task.
- typedef std::future<Result> return_type;
-
- /// The constructor extracts the future from the packaged task.
- explicit async_result(completion_handler_type& h)
- : future_(h.get_future())
- {
- }
-
- /// Returns the packaged task's future.
- return_type get()
- {
- return std::move(future_);
- }
-
- private:
- return_type future_;
- };
-
- #else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
- // || defined(GENERATING_DOCUMENTATION)
-
- template <typename Result, typename Signature>
- struct async_result<std::packaged_task<Result()>, Signature>
- {
- typedef std::packaged_task<Result()> completion_handler_type;
- typedef std::future<Result> return_type;
-
- explicit async_result(completion_handler_type& h)
- : future_(h.get_future())
- {
- }
-
- return_type get()
- {
- return std::move(future_);
- }
-
- private:
- return_type future_;
- };
-
- #define ASIO_PRIVATE_ASYNC_RESULT_DEF(n) \
- template <typename Result, \
- ASIO_VARIADIC_TPARAMS(n), typename Signature> \
- class async_result< \
- std::packaged_task<Result(ASIO_VARIADIC_TARGS(n))>, Signature> \
- { \
- public: \
- typedef std::packaged_task< \
- Result(ASIO_VARIADIC_TARGS(n))> \
- completion_handler_type; \
- \
- typedef std::future<Result> return_type; \
- \
- explicit async_result(completion_handler_type& h) \
- : future_(h.get_future()) \
- { \
- } \
- \
- return_type get() \
- { \
- return std::move(future_); \
- } \
- \
- private: \
- return_type future_; \
- }; \
- /**/
- ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_ASYNC_RESULT_DEF)
- #undef ASIO_PRIVATE_ASYNC_RESULT_DEF
-
- #endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
- // || defined(GENERATING_DOCUMENTATION)
-
- } // namespace asio
-
- #include "asio/detail/pop_options.hpp"
-
- #endif // defined(ASIO_HAS_STD_FUTURE_CLASS)
- // || defined(GENERATING_DOCUMENTATION)
-
- #endif // ASIO_PACKAGED_TASK_HPP
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