Re: [Boost-users] Boost.Asio, 0MQ, and Windows

Subject: Re: [Boost-users] Boost.Asio, 0MQ, and Windows
From: Damien Kick (dkick_at_[hidden])
Date: 2013-08-12 14:50:24

Damien Kick <dkick <at> shoretel.com> writes:

> <sigh/> It's so annoying because I have this feeling that there is
> probably just one stupid little conversion function that I need to
> be calling but it continues to elude me :(

And ... that missing conversion function was simply a mother father
Chinese dentist cast.  <sigh/> I had managed to get lost in the swirl
of GetStdHandle, DuplicateHandle, WSADuplicateSocket, and the odd
_open_osfhandle ...  But then, after all of that fuss, I find that:

   zmq::context_t zenv(1);
   zmq::socket_t zocket(zenv, ZMQ_PUSH);
   SOCKET zfd;
   std::size_t zfd_size = sizeof(zfd);
   zocket.getsockopt(ZMQ_FD, &zfd, &zfd_size);
   HANDLE handle = (HANDLE)zfd;
   boost::asio::io_service ios;
   boost::asio::windows::stream_handle io(ios, handle);
   io.async_read_some(
       boost::asio::null_buffers(),
       [](const boost::system::error_code& err, std::size_t) { });

Does not compile:

    2>.../stream_handle_service.hpp(195): error C2248: \
        'boost::asio::detail::win_iocp_handle_service::async_read_some' : \
        cannot access private member declared in class \
        'boost::asio::detail::win_iocp_handle_service'

Sure enough, I find ...

    class win_iocp_handle_service
    {
    private:
      // Prevent the use of the null_buffers type with this service.
      // [... snip ...]
      template <typename Handler>
      void async_read_some(implementation_type& impl,
          const null_buffers& buffers, Handler& handler);
    // [... snip ...]
    };
        
And so, unless I'm once again missing something obvious (like casting
a SOCKET into a HANDLE), it doesn't seem that the approach of using
the ZMQ_FD and boost::asio::null_buffers is going to work for me on
both POSIX and Windows.