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Diffstat (limited to 'boost/asio/use_awaitable.hpp')
-rw-r--r-- | boost/asio/use_awaitable.hpp | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/boost/asio/use_awaitable.hpp b/boost/asio/use_awaitable.hpp new file mode 100644 index 0000000000..8764b3d2d2 --- /dev/null +++ b/boost/asio/use_awaitable.hpp @@ -0,0 +1,73 @@ +// +// 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 +{ + BOOST_ASIO_CONSTEXPR use_awaitable_t() + { + } +}; + +/// 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 |