device not open error + QIODevice::write - c++

Question

I get the error:
QIODevice::write (QTcpSocket): device not open.
After trying , I think problem is passing parameter server->nextPendingConnection() into object. Can someone has idea how to do it correctly?
My understanding is that object for socketClient is not initialised properly.
I'm using Ubuntu with Qt.
I am implementing server using Qt. The server part has two classes based on QTcpServer and QTcpSocket.
say Server and SocketClient.
I am creating object of SocketClient in server and for testing purpose I opened telnet session and wants to see that server write "hello" on terminal. But somehow its not working. Can someone please advice me where I am making mistake.
Server::Server(QObject *parent) : QObject(parent)
{
server_obj = new QTcpServer( this );
}
void Server::startServer()
{
connect( server_obj, SIGNAL( newConnection() ), this, SLOT( incomingConnection() ) );
if( !server_obj->listen( QHostAddress::Any, 9999) )
{
qDebug() << " Server failed to get started";
}
else
{
qDebug() << " Server started"; // this is successful
}
}
void Server::incomingConnection()
{
socketforClient = new SockClient( server_obj->nextPendingConnection() );// has a doubt on nextPendingconection??
//only for testing remove it
socketforClient->writeToClient();
}
Class for Client
* Description: Its a constructor.I have changed default constructor to add QTcpSocket* object in parameter.I used this constructor in void Server::incomingConnection()
*/
SockClient::SockClient(QObject *parent,QTcpSocket* socket ) : QObject(parent)
{
socketClient = new QTcpSocket( socket );
qDebug() << " we are in constructor of 1st sockclient ";
}
// this is for testing purpose only
void SockClient::writeToClient()
{
socketClient->write(" hello world\r\n");
socketClient->flush();
socketClient->waitForBytesWritten(3000);
}
//header file of SockClient
class SockClient : public QObject
{
Q_OBJECT
public:
explicit SockClient( QObject *parent, QTcpSocket* socket= 0 ); // I have created
void writeToClient(); // This is for testing purpose
~SockClient();
signals:
private slots:
void readClient();
private:
void sendResponsetoMops();
QTcpSocket *socketClient;
quint16 nextBlockSize;
public slots:
};

Answer 1

You use:
socketClient = new QTcpSocket( socket );
Try to use following code instead:
socketClient = socket;
And use
socketforClient = new SockClient(this, server->nextPendingConnection() );
instead of
socketforClient = new SockClient( server->nextPendingConnection() );