Re: [Boost-users] boost::Asio async_accept not throwing exception

Acceptor.async_accept(NewConnection->socket(),boost::bind(&TCPServer::HandleAccept,this, NewConnection,boost::asio::placeholders::error));     }     catch(std::exception& e)     {        cout<<"exception"<

Another program is already listening on the port "13" (A service version of the same program). When this new program tries to listen (async_accept) on port "13", no exception is thrown!.

How can I check weather the port is already open?

async_XXX functions do not throw, they guarantee that the completion handler will always be invoked. So what you should check is the error_code in your completion handler.