Hi Gaetano, On Apr 2, 2012, at 11:07 AM, Gaetano Mendola wrote:
Hi all, reading the manual I see that ip::tcp::socket thread safety on shared object is not safe.
In my application I'm using:
ip::tcp::socket::async_connect boost::asio::async_read( ip::tcp::socket , ...)
the application queue an async_read or an async_connect inside the receiving handler (in case of error it retry the connection).
From an external thread (to stop the reception) I perform a:
ip::tcp::socket::shutdown ip::tcp::socket::close
do I have realy to synchronize the async_connect/async_read with shutdown/close ?
Using a mutex to protect those calls seems an overkill, may be shutdown and close can be called in concurrency with async_connect/async_read and the documentation is just conservative?
I would stick to what the documentation says. The io_service is thread-safe, so to synchronize the socket operations from different threads, you can use io_service::post() from your "external thread". Implement a function that performs the shutdown() and close() calls, and post that function as a completion handler with io_service.post(), using the io_service instance that is handling your async_connect() and async_read() calls. That way, all of the thread-unsafe ip::tcp::socket calls will occur in the single thread that is running io_service.run(), guaranteeing thread safety. -Brad