[Boost-bugs] [Boost C++ Libraries] #3627: boost::asio::async_read() cannot be used with null_buffers()

Subject: [Boost-bugs] [Boost C++ Libraries] #3627: boost::asio::async_read() cannot be used with null_buffers()
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2009-11-16 09:55:23

#3627: boost::asio::async_read() cannot be used with null_buffers()
----------------------------------------------------------------+-----------
 Reporter:  Dmitry Goncharov <dgoncharov@…>                     |       Owner:  chris_kohlhoff
     Type:  Bugs                                                |      Status:  new           
Milestone:  Boost 1.41.0                                        |   Component:  asio          
  Version:  Boost 1.40.0                                        |    Severity:  Problem       
 Keywords:  asio async_read null_buffers                        |  
----------------------------------------------------------------+-----------
 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.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/3627>
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