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.

Qt Code: 
  1. Server::Server(QObject *parent) : QObject(parent)
  2.     {
  3.       server_obj = new QTcpServer( this ); 
  4.     }
  5.  
  6.     void Server::startServer()
  7.     {
  8.       connect( server_obj, SIGNAL( newConnection() ), this, SLOT( incomingConnection() ) );
  9.       if( !server_obj->listen( QHostAddress::Any, 9999) )
  10.       {
  11.         qDebug() << " Server failed to get started";
  12.       }
  13.       else
  14.       {
  15.        qDebug() << " Server started"; // this is successful
  16.       }
  17.     }
  18.  
  19.  
  20.     void Server::incomingConnection()
  21.     {
  22.       socketforClient = new SockClient( server_obj->nextPendingConnection() );// has a doubt on nextPendingconection?? May be Problem HERE..
  23.  
  24.       //only for testing remove it
  25.       socketforClient->writeToClient();
  26.     }
To copy to clipboard, switch view to plain text mode 
Class for Client

Qt Code: 
  1. * Description: Its a constructor.I have changed default constructor to add QTcpSocket* object in parameter.I used this constructor in  void Server::incomingConnection()
  2.      */
  3.     SockClient::SockClient(QObject *parent,QTcpSocket* socket ) : QObject(parent)
  4.     {
  5.       socketClient = new QTcpSocket( socket ); // PROBLEM HERE ?
  6.  
  7.      qDebug() << " we are in constructor of 1st sockclient ";
  8.  
  9.     }
  10.  
  11.  
  12.  
  13.     // this is for testing purpose only
  14.  
  15.     void SockClient::writeToClient()
  16.     {
  17.        socketClient->write(" hello world\r\n");
  18.        socketClient->flush();
  19.        socketClient->waitForBytesWritten(3000);
  20.  
  21.     }
To copy to clipboard, switch view to plain text mode 

//header file of SockClient

Qt Code: 
  1. class SockClient : public QObject
  2.     {
  3.       Q_OBJECT
  4.     public:
  5.  
  6.      explicit  SockClient( QObject *parent, QTcpSocket* socket= 0 ); // I have created
  7.         void writeToClient(); // This is for testing purpose
  8.      ~SockClient();
  9.     signals:
  10.  
  11.     private slots:
  12.       void readClient();
  13.  
  14.     private:
  15.       void sendResponsetoMops();
  16.  
  17.       QTcpSocket *socketClient;
  18.  
  19.       quint16 nextBlockSize;
  20.  
  21.     public slots:
  22.     };
To copy to clipboard, switch view to plain text mode