void MainWindow::on_pushButton_clicked()
{
    meinServer = new QTcpServer(this);
    meinServer->listen(QHostAddress::Any, 12345);

    connect(meinServer, SIGNAL(newConnection()), this, SLOT(sendText()));


}

void MainWindow::sendText()
{
    QTcpSocket * ClientSocket = meinServer->nextPendingConnection();

    char * buffer = "Hallo Welt";

    ClientSocket->write(buffer);
    ClientSocket->disconnectFromHost();

}