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
< Předmět: Re: [Boost-users] Synchronous problem with asio
< Datum: 11.8.2009 14:36:40
< ----------------------------------------
< 2009/8/11 Dan Benčík :
< > 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 :)
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