| // |
| // 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 ASIO_USE_AWAITABLE_HPP |
| #define ASIO_USE_AWAITABLE_HPP |
| |
| #if defined(_MSC_VER) && (_MSC_VER >= 1200) |
| # pragma once |
| #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) |
| |
| #include "asio/detail/config.hpp" |
| |
| #if defined(ASIO_HAS_CO_AWAIT) || defined(GENERATING_DOCUMENTATION) |
| |
| #include "asio/awaitable.hpp" |
| |
| #include "asio/detail/push_options.hpp" |
| |
| 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 |
| { |
| ASIO_CONSTEXPR use_awaitable_t() |
| { |
| } |
| }; |
| |
| /// A completion token object that represents the currently executing coroutine. |
| /** |
| * See the documentation for asio::use_awaitable_t for a usage example. |
| */ |
| #if defined(ASIO_HAS_CONSTEXPR) || defined(GENERATING_DOCUMENTATION) |
| constexpr use_awaitable_t<> use_awaitable; |
| #elif defined(ASIO_MSVC) |
| __declspec(selectany) use_awaitable_t<> use_awaitable; |
| #endif |
| |
| } // namespace asio |
| |
| #include "asio/detail/pop_options.hpp" |
| |
| #include "asio/impl/use_awaitable.hpp" |
| |
| #endif // defined(ASIO_HAS_CO_AWAIT) || defined(GENERATING_DOCUMENTATION) |
| |
| #endif // ASIO_USE_AWAITABLE_HPP |