QLocalSocket doesn't send anything

Question

well, i'm still trying to get a IPC running through a QLocalSocket. Obviously my socket connects, the connection gets accepted, but when i try to send something

void ServiceConnector::send_MessageToServer(QString message) {

    if(!connected){
        m_socket->connectToServer(m_serverName);
        m_socket->waitForConnected();

    }

    char str[] = {"hallo welt\0"};
    int c = m_socket->write(str,strlen(str));
    qDebug() << "written: " << c;
}

i get no response...the server's socket does just nothing.

server's read implementation:

void ClientHandler::socket_new_connection() {

    logToFile("incoming connection");

    clientConnection = m_server->nextPendingConnection();

    socket_StateChanged(clientConnection->state());

    auto conn = connect(clientConnection, SIGNAL(disconnected()),this, SLOT(socket_disconnected()));
    conn = connect(clientConnection, SIGNAL(stateChanged(QLocalSocket::LocalSocketState)),this,SLOT(socket_StateChanged(QLocalSocket::LocalSocketState)));
    conn = connect(clientConnection, SIGNAL(readyRead()), this, SLOT(socket_readReady()));

    clientConnection->waitForReadyRead();
    socket_readReady();
}
void ClientHandler::socket_readReady(){
    logToFile("socket is ready to be read");

    logToFile((clientConnection->isOpen())? "open: true":"open: false");
    logToFile((clientConnection->isReadable())? "readable: true":"readable: false");

    QDataStream in(clientConnection);
    in.setVersion(QDataStream::Qt_4_0);
    if (clientConnection->bytesAvailable() < (int)sizeof(quint16)) {
        return;
    }

    QString message;
    in >> message;

    logToFile("Message recieved" + message);

    send(message);
    emit messageReceived(message);
}

outputs:

client:

[Debug]: ConnectingState 
[Debug]: ConnectedState 
[Debug]: socket_connected 
[Debug]: written:  10 

server:

[Debug]: incoming connection
[Debug]: socket is ready to be read
[Debug]: open: true
[Debug]: readable: true

the socket's readReady() signal is never emitted, so i decided to use

clientConnection->waitForReadyRead();
socket_readReady();

...but obviously that doesn't work either. waitForReadyRead is fired immediately after the write function of the client, which i think means that it is now ready to read...

[edit] the auto conn = connection(...) was for debugging, to check if they connect properly....they do

Answer 1

Note: you should really check the return value of waitForConnected(). There's no point in proceeding further if the client doesn't manage to connect to the server.

But I think your actual issue is that you're writing a simple 8-bit string like "hallo welt\0" but you're reading with QDataStream which expects a binary format (for QString, that means unicode, and length first), this doesn't match.