Dear Zachary, thank you VERY MUCH. You can't imagine how much time I spent looking for an answer as simple as the one of yours! Finally my code works:) All the best, Daniel. < ------------ Původní zpráva ------------ < Od: Zachary Turner <divisortheory@gmail.com> < Předmět: Re: [Boost-users] Synchronous problem with asio < Datum: 11.8.2009 14:36:40 < ---------------------------------------- < 2009/8/11 Dan Benčík <eubie@seznam.cz>: < > Dear everybody, < > I have a problem using asio. My client/server application requires only < synchronous communication. So, using the examples for synchro from the boost < homepage, I have set up two procedures to send and receive data. Their code is < as follows: < > < > void vReceive(tcp::socket & socket, std::string & szDest){ < > char szTmp_Buf [BUF_LEN + 1]; < > szDest = ""; < > std::cout << "Entering vReceive . . ." << std::endl; < > < > for (;;){ < > char szBuf [BUF_LEN]; < > boost::system::error_code error; < > uInt uiBytes_Recv = socket.read_some(boost::asio::buffer(szBuf), error); < > std::cout << " Read " << uiBytes_Recv << " bytes" << std::endl; < > if (error == boost::asio::error::eof) < > break; // Connection closed cleanly by peer. < > else if (error) < > throw boost::system::system_error(error); // Some other error. < > < > memcpy((void*) szTmp_Buf, (void*) szBuf, uiBytes_Recv ); < > szTmp_Buf[ uiBytes_Recv ] = '\0'; < > szDest += szTmp_Buf; < > }; < > std::cout << "Received" << szDest << std::endl; < > std::cout << "Leaving vReceive . . ." << std::endl << std::endl; < > }; < > < > void vSend(tcp::socket & socket, std::string & szSrc){ < > std::cout << "Entering vSend . . . " << std::endl; < > std::cout << "Sending " << szSrc << std::endl; < > boost::system::error_code ignored_error; < > boost::asio::write(socket, boost::asio::buffer(szSrc), < boost::asio::transfer_all(), ignored_error); < > std::cout << "Leaving vSend . . . " << std::endl << std::endl; < > }; < > < > < > These procedures are just wrappers for the lines of code extracted from the < boost examples. < > < > < > In my test applications, the client calls < > < > vReceive(socket, szDate); < > vSend(socket, std::string("Chop Suey!") ); < > vReceive(socket, szDate); < > vSend(socket, std::string("Halo")); < > < > and the server calls < > < > vSend(socket, message); < > vReceive(socket, szReceived); < > vSend(socket, message); < > vReceive(socket, szReceived); < > < > just to test the functionality. The problem is that both applications freeze < after the first information exchange, as I have depicted on the following < picture ( http://eubie.sweb.cz/asio_problem.JPG ). It seems that vReceive() < procedure on the client side doesn´t finish while vSend() finishes on the server < side. So, does anybody have any idea, what might be wrong? < > < > Just in case someone wanted to replicate the problem, I uploaded the complete < sources to http://eubie.sweb.cz/asio_problem.rar file. < > < > Thank you all in advance, Daniel. < > _______________________________________________ < > Boost-users mailing list < > Boost-users@lists.boost.org < > http://lists.boost.org/mailman/listinfo.cgi/boost-users < > < < You're using boost::asio::write() to overcome the limitation of < socket.send() that it might not send all the data in one pass, so why < not do the same for reading? Instead of making the loop yourself, < just use boost::asio::read(). Furthermore, you don't need to use the < completion condition version with transfer_all(), you can use the < alternate overload, which automatically does that for you. < < boost::asio::write(socket_, boost::asio::buffer(szOutput, szOutput.length())); < < boost::asio::read(socket_, boost::asio::buffer(szInput, szInput.length())); < < Short and sweet, that's all you need :) < _______________________________________________ < Boost-users mailing list < Boost-users@lists.boost.org < http://lists.boost.org/mailman/listinfo.cgi/boost-users < < <