QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread

aminM

hi.
excuse me. I am weak in English.
I'm trying to write a program that reads UDP datagrams with separate thread.

class NetRecieverThread : public QThread
{
    Q_OBJECT
public:
    QUdpSocket *m_Socket;
    int m_iPortNum;
    QString m_stIpAddress;

    NetRecieverThread(QObject *parent ,QString  sAddress ,int PortNum )
    {
        m_iPortNum = PortNum;
        m_stIpAddress = sAddress;
        m_Socket = new QUdpSocket (this);
        bool bl = m_Socket ->bind(QHostAddress(sAddress),PortNum);
        bl = 0;

        //connect(m_Socket ,SIGNAL(readyRead()),this,SLOT(readData()));

    }

    void run() Q_DECL_OVERRIDE
    {
        while(true)
        {

            QByteArray datagram;
            bool ReadyRead = false;
            while(!ReadyRead)
                ReadyRead = m_Socket->waitForReadyRead(30000);

            datagram.resize(m_Socket->pendingDatagramSize());

            QHostAddress sender;
            quint16 senderPort;


           int iSize =  m_Socket->readDatagram(datagram.data(),datagram.size(),&sender,&senderPort);
           if(iSize <=0)
               return;


            char *data = datagram.data();
             quint8 RecData = data[0];
             qDebug() <<"\n \n\ NetRecieverThread : Rec Data "<<RecData<<"Thread Information : "<< QThread::currentThread()<<QThread::currentThreadId();
            emit resultReady(datagram);

        }
    }
signals:
    void resultReady(QByteArray datagram);

};

//--------------------------------------------------------------------
//--------------------------------------------------------------------

class NetRecieveManager : public QObject
{
    Q_OBJECT
     NetRecieverThread *tRec;
public:
    NetRecieveManager()
    {
    }



    void startWorkInAThread()
    {

       tRec = new NetRecieverThread(0,"127.0.0.1",56071);
       connect(tRec, &NetRecieverThread::resultReady, this, &NetRecieveManager::handleResults);

      tRec->start();

    }
private slots:
    void handleResults(QByteArray datagram)
    {
       char *ch  = datagram.data();
       quint8 RecData = ch[0];
       qDebug() <<"NetRecieveManager: Rec Data "<<RecData<<"Thread Information : "<< QThread::currentThread()<<QThread::currentThreadId()<<"\n \n ";

    }

};

//--------------------------------------------------------------------
//--------------------------------------------------------------------
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    //------------------------------------------------------
    NetRecieveManager myob;
    QThread  NetMangerThread;
    NetMangerThread.setObjectName("NetMangerThread");

    myob.startWorkInAThread();
    myob.moveToThread(&NetMangerThread);
    NetMangerThread.start();
    //------------------------------------------------------

    return a.exec();
}

then output program is :

 QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread

 
 NetRecieverThread : Rec Data  208 Thread Information :  NetRecieverThread(0xb625c8) 0xe10
NetRecieveManager: Rec Data  208 Thread Information :  QThread(0x12fedc, name = "NetMangerThread") 0xb38 
 
 
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread

 
 NetRecieverThread : Rec Data  209 Thread Information :  NetRecieverThread(0xb625c8) 0xe10
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread
NetRecieveManager: Rec Data  209 Thread Information :  QThread(0x12fedc, name = "NetMangerThread") 0xb38 
 
 
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread

 
 NetRecieverThread : Rec Data  210 Thread Information :  NetRecieverThread(0xb625c8) 0xe10
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread
NetRecieveManager: Rec Data  210 Thread Information :  QThread(0x12fedc, name = "NetMangerThread") 0xb38 
 
 
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread

 
 NetRecieverThread : Rec Data  211 Thread Information :  NetRecieverThread(0xb625c8) 0xe10
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread
NetRecieveManager: Rec Data  211 Thread Information :  QThread(0x12fedc, name = "NetMangerThread") 0xb38 
 
 
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread

 
 NetRecieverThread : Rec Data  212 Thread Information :  NetRecieverThread(0xb625c8) 0xe10
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread
NetRecieveManager: Rec Data  212 Thread Information :  QThread(0x12fedc, name = "NetMangerThread") 0xb38

everything is ok. both 2 threads work good. i dont know why get this message
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread

Is the problem will be.
thanks

SGaist

Hi and welcome to devnet,

The constructor of NetRecieverThread is run in the main thread so m_Socket is created in the main thread. On the other hand the run method is called in the thread managed by QThread that's why you get the message.

aminM

This post is deleted!

aminM

@SGaist
thanks SGait
ok.
i change code and move create m_socket to run function and solved problem.

    void run() Q_DECL_OVERRIDE
    {
        m_Socket = new QUdpSocket (0);
        bool bl = m_Socket ->bind(QHostAddress(m_stIpAddress),m_iPortNum);
     while(true)
     {
       .
       .
       .

SGaist

Don't forget to delete the socket before the end of run otherwise you'll have a memory leak