How to assign an already connected native socket type (TCP) in Boost.ASIO

Question

Is there a way that allows using an already connected socket in ASIO?

Trying to send one request; ip::tcp::socket::assign gives randomly 2 different segfaults at 2 different places. One is before calling the callback (on op_queue_acess::next ) and other is after the callback (on boost::asio::detail::task_io_service_operation::complete (func_ is equal to 0 and tries to be executed)). So I guess it does not work with connected sockets.

Edit:

The case is, I have a connected native descriptor (actually a socket underlying under another library) and I want to assign it to a new, empty ip::tcp::socket so that I can be notified when the socket is read ready (using the socket::async_read_some with null buffers) and use the library in a non-blocking way.

Sample code follows as:

class C
{
 ip::tcp::socket socket_;
 const char connection_info_[] = "...";
 TPLibrary tp_;

 void start()
 {
  .
  .
  tp_.connect(connection_info);
  socket_.assign(ip::tcp::v4(), tp_.nativeSocket());
 }
}

Then using async_read on this socket gives the said seg fault, sometimes its after calling callback, sometimes before.

EDIT: Now I have removed everything and only the tcp::socket and assigning to the socket left but still boost gives segfaults. Is it because io_service is on a dynamically loaded library and socket is in another dynamically loaded library with a reference to io_service on the main library?

Answer 1

You can assign already connected socket to boost::asio socket and enjoy boost features then onwards.

from below link you can find how to use assign API.

http://www.boost.org/doc/libs/1_54_0/doc/html/boost_asio/reference/basic_stream_socket/assign/overload1.html

Let me know if you have any query.

Edit:

Now if your problem is about non-blocking read as async_read_some is non blocking then use the read_some as follows

boost::asio::async_read(*p_socket, boost::asio::buffer(&buffer[index], remaining_len2read), read_handler);

The above API is blocking and will not return until all the data is received.

Answer 2

The problem was about dynamic linkage that I was using. As an answer to the question tcp::socket::assign works fine on connected sockets.