EVOLUTION-MANAGER
Edit File: use_awaitable.hpp
// // use_awaitable.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 BOOST_ASIO_USE_AWAITABLE_HPP #define BOOST_ASIO_USE_AWAITABLE_HPP #if defined(_MSC_VER) && (_MSC_VER >= 1200) # pragma once #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) #include <boost/asio/detail/config.hpp> #if defined(BOOST_ASIO_HAS_CO_AWAIT) || defined(GENERATING_DOCUMENTATION) #include <boost/asio/awaitable.hpp> #include <boost/asio/detail/push_options.hpp> namespace boost { namespace asio { /// A completion token that represents the currently executing coroutine. /** * The @c use_awaitable_t class, with its value @c use_awaitable, is used to * represent the currently executing coroutine. This completion token may be * passed as a handler to an asynchronous operation. For example: * * @code awaitable<void> my_coroutine() * { * std::size_t n = co_await my_socket.async_read_some(buffer, use_awaitable); * ... * } @endcode * * When used with co_await, the initiating function (@c async_read_some in the * above example) suspends the current coroutine. The coroutine is resumed when * the asynchronous operation completes, and the result of the operation is * returned. */ template <typename Executor = executor> struct use_awaitable_t { /// Default constructor. BOOST_ASIO_CONSTEXPR use_awaitable_t() { } /// Adapts an executor to add the @c use_awaitable_t completion token as the /// default. template <typename InnerExecutor> struct executor_with_default : InnerExecutor { /// Specify @c use_awaitable_t as the default completion token type. typedef use_awaitable_t default_completion_token_type; /// Construct the adapted executor from the inner executor type. executor_with_default(const InnerExecutor& ex) BOOST_ASIO_NOEXCEPT : InnerExecutor(ex) { } }; /// Type alias to adapt an I/O object to use @c use_awaitable_t as its /// default completion token type. #if defined(BOOST_ASIO_HAS_ALIAS_TEMPLATES) \ || defined(GENERATING_DOCUMENTATION) template <typename T> using as_default_on_t = typename T::template rebind_executor< executor_with_default<typename T::executor_type> >::other; #endif // defined(BOOST_ASIO_HAS_ALIAS_TEMPLATES) // || defined(GENERATING_DOCUMENTATION) /// Function helper to adapt an I/O object to use @c use_awaitable_t as its /// default completion token type. template <typename T> static typename T::template rebind_executor< executor_with_default<typename T::executor_type> >::other as_default_on(BOOST_ASIO_MOVE_ARG(T) object) { return typename as_default_on_t<typename decay<T>::type>::type( BOOST_ASIO_MOVE_CAST(T)(object)); } }; /// A completion token object that represents the currently executing coroutine. /** * See the documentation for boost::asio::use_awaitable_t for a usage example. */ #if defined(BOOST_ASIO_HAS_CONSTEXPR) || defined(GENERATING_DOCUMENTATION) constexpr use_awaitable_t<> use_awaitable; #elif defined(BOOST_ASIO_MSVC) __declspec(selectany) use_awaitable_t<> use_awaitable; #endif } // namespace asio } // namespace boost #include <boost/asio/detail/pop_options.hpp> #include <boost/asio/impl/use_awaitable.hpp> #endif // defined(BOOST_ASIO_HAS_CO_AWAIT) || defined(GENERATING_DOCUMENTATION) #endif // BOOST_ASIO_USE_AWAITABLE_HPP