can't read from qt4 tcpSocket

This is a discussion on can't read from qt4 tcpSocket within the Networking/Device Communication forums, part of the General Programming Boards category; Hi, I am using Qt4 to develop a simple chat client for school. I have already asked this question on ...

  1. #1
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    can't read from qt4 tcpSocket

    Hi,

    I am using Qt4 to develop a simple chat client for school. I have already asked this question on qtforums.org but never got a response, I am hoping that someone here has some knowledge of Qt and can shed some light on this problem for me. I have basically taught myself OO programming for this project, so I realise that my design is probably not the best, but this bug is baffling me. Here is the relevant code

    Code:
    void Kether::readData()
    {
        //qDebug("In readData start");
        QDataStream in(tcpSocket);
        in.setVersion(QDataStream::Qt_4_2);
        /*
        if (blocksize == 0)
        {
            if (tcpSocket->bytesAvailable() < (int)sizeof(quint16))
            {
                qDebug("in first return");
                return;
            }
            in >> blocksize;
        }
    
        if (tcpSocket->bytesAvailable() < blocksize)
        {
            qDebug("in second return");
            return;
        }
        */
        QString receivedMessage;
        in >> receivedMessage;
        qDebug() << "receivedMessage:" << receivedMessage;
    
        ui.chatWindow->append(receivedMessage);
        qDebug("In readData end");
    }
    This slot/function is executed everytime the readyRead() signal is emitted which means that data is available to read from the network socket. The function is called, but receivedMessage is always blank so it isn't reading from the socket. But there is no reason it shouldn't, it's definetely connected and will send data to netcat and this function is called to read the data and display except it only reads a blank string. I would appreciate any replies or suggestions, I will post all code on request, it's just that's it's a few hundred lines so I am a little hesitant.

    Thanks in advance,

    Calef13

  2. #2
    CSharpener vart's Avatar
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    Location
    Rishon LeZion, Israel
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    >> is for the formatted input
    socket should provide you with binary data. Shouldn't you use some binary input functions?
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  3. #3
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    Well, the examples simply read into a qstring and they work fine, but you are right the datastream is for binary writing, I want to try this but what type of variable should I use, will an arry work okay? I used those when I used the c sockets library.

  4. #4
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    ok I just tried it with QTextStream and it worked! Thank you so much, you have no idea how long I have been fighting with this, seriously thanks a lot.

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