Yes, error checking is also performed in the accept handler (HandleAccept function). The code never reaches the async_accept handler. Normally, when trying to listen on a port the asyn_accept handler must be called with the error set if some error occurs. But this is not happening! I am running the same version of the program as a service in the first phase, then trying to debug a command line version of the same program from Visual Studio. What could be the reason? Thanks, Lloyd On 11/22/10, Igor R wrote:

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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. _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

Thanks, I shall post it in ASIO list. On 11/22/10, Igor R wrote:

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Yes, error checking is also performed in the accept handler (HandleAccept function). The code never reaches the async_accept handler.

Well, then maybe it's a bug. I believe it's worth cross-posting this question to asio-users. _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users