// // deferred_4.cpp // ~~~~~~~~~~~~~~ // // Copyright (c) 2003-2023 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) // #include #include using asio::deferred; template auto async_wait_twice(asio::steady_timer& timer, CompletionToken&& token) { return timer.async_wait( deferred( [&](std::error_code ec) { std::cout << "first timer wait finished: " << ec.message() << "\n"; timer.expires_after(std::chrono::seconds(1)); return timer.async_wait(deferred); } ) )( deferred( [&](std::error_code ec) { std::cout << "second timer wait finished: " << ec.message() << "\n"; return deferred.values(42); } ) )( std::forward(token) ); } int main() { asio::io_context ctx; asio::steady_timer timer(ctx); timer.expires_after(std::chrono::seconds(1)); async_wait_twice( timer, [](int result) { std::cout << "result is " << result << "\n"; } ); ctx.run(); return 0; }