id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
3627	boost::asio::async_read() cannot be used with null_buffers()	Dmitry Goncharov <dgoncharov@…>	chris_kohlhoff	"An attempt to use async_read() with null_buffers() causes the handler to be invoked even when the underlying file descriptor is not yet available for reading.

The following test demonstrates the problem

void test_async_read()
{
    struct local
    {
        static void on_ready(boost::system::error_code const& error, int* invoked)
        {
            BOOST_CHECK(!error);
            *invoked = 1;
        }
    };

    int p[2];
    int const s = pipe(p);
    BOOST_CHECK(0 == s);

    boost::asio::io_service ios;
    boost::asio::posix::stream_descriptor sd(ios, p[0]);
    ios.reset();
    int invoked = 0;
    boost::asio::async_read(sd, boost::asio::null_buffers(), boost::bind(&local::on_ready, _1, &invoked));
    ios.poll_one();
    BOOST_CHECK(!invoked); // doesn't pass
}

This test doesn't pass on linux using either epoll or select multiplexing mechanism. This test also doesn't pass on freebsd using either kqueue or select multiplexing mechanism."	Feature Requests	new	To Be Determined	asio	Boost 1.40.0	Not Applicable		asio async_read null_buffers