Hi, below is some code where boost::asio::io_service::work is added, and then immediately removed. After that, I call async_wait on a steady_timer, but it does not work: io.run() RETURNS IMMEDIATELY, and IGNORES the async_wait. Is this intended? (I was rather surprised, because I thought that the async_wait would schedule new work, but it does not work). If I cange the code-line #define WEIRD_BEHAVIOUR to #undef WEIRD_BEHAVIOUR then I have my expected behaviour. Thanks, ajneu #include <iostream> #include <chrono> #include <experimental/optional> #include <boost/asio.hpp> #include <boost/asio/steady_timer.hpp> #define WEIRD_BEHAVIOUR int main() { boost::asio::io_service io; std::experimental::optional<boost::asio::io_service::work> work; #ifdef WEIRD_BEHAVIOUR work.emplace(io); work = std::experimental::nullopt; #endif boost::asio::steady_timer timer(io, std::chrono::milliseconds{1000}); timer.async_wait([](const boost::system::error_code &ec) { std::cout << ((!ec) ? "done" : "err") << std::endl; }); io.run(); }