problems when deleting class inherit

kickoune103

hello,
i have problem, i have segmentation fault when i deleting inherit class. executing destructor.i have delete all signal. same problems.
i delete tx_rs_modbus, call delete tx_rs_device and seg fault!

it's crazy...
please help me.

img debug

base class:

//your code here
```class tx_rs_device:public QObject
{
   Q_OBJECT


public:
    tx_rs_device(Trame* Parent);
    ~tx_rs_device();

    const int GetIntervalTx();
    void SetIntervalTx( int pint );

    const QString getTrameTx();
    void setTrameTx(QString pTx);

    void start();

    QVariantList getConf(void);
    void  setConf(QVariantList);


    tx_rs_modbus *getModbustx();

    bool traiteRecuRx();

    QTime getTimeLastTx();

    void sendTx();



 enum enumModeTx{MANUEL,ONE_SHOT,CYCLIQUE,AUTO};

//signals:
 //void started();

protected:
        Trame       *MaTrame;
        enumModeTx  m_ModeTx;
        QString     m_TrameTx;
        QTimer      m_TimerTx;

        quint32     cptTx;
        quint32     cptTxOK;
        quint32     cptTxKO;
        QTime       m_TicksLastTx;

        bool        TxEnCours;
       // bool        first;
       // bool        RxRecu;

public slots:
       virtual void requeteTx();
        void timeOut();
};
class tx_rs_modbus:public tx_rs_device
{
    Q_OBJECT


 public:
    enum enumTypeTx{WRITE=0,READ};

     tx_rs_modbus(Trame* Parent,enumTypeTx pType);
     tx_rs_modbus(Trame* Parent,enumTypeTx pType,bool pWrite);

     ~tx_rs_modbus();



      enumTypeTx getTypeTx(void);
      void setTypeTx(enumTypeTx pType);

      QModbusDataUnit::RegisterType getTypeRegister();
       void setTypeRegister(QModbusDataUnit::RegisterType pRegister);

       int  getAdresseModbus();
       void setAdresseModbus(int pAdresse);

       QVariantList getConf();
       void setConf(QVariantList pConf);

private:
      enumTypeTx  m_type_tx;
      bool        writeWhenChange;
      QByteArray  *m_byte_array_remote;
      QModbusDataUnit::RegisterType m_type_register;
      int m_adresse;
      //int m_periode_tx;

        bool m_reply;

   public slots:
     void isStarted();
     void TrameChange(); //quand les champs.
     void requeteTx();
     void reply();
};

mrjj

Hi
Could it be a double delete ?
If you assign parent ( Trame *) to it , the parent will delete its child automatically, so if you manually call delete on the child,
it might result in double delete.

http://doc.qt.io/qt-5/objecttrees.html

kickoune103

in class Trame, have a properties tx_rs_modbus*,
when i deleting this to create a new trame object, i deleting properties to create a other.
delete tx_rs_modbus call a delte tx_rs_device and seg fault...

jsulm

@kickoune103 Do I understand you correctly: you're calling base class destructor explicitly? This is not needed. Can you show both destructors?

kickoune103

//trame rs is tx_rs_device.

    union t_trame_rs{
            tx_rs_device *tx;
            rx_rs *rx;
    };

//on my case trame_rs_tx is allocate with new tx_rs_modbus().

```void Trame::kill_m_trame()
{

    switch ( MonProt->GetILiaison())
    {
       case Protocole::LIAISON_RS:
        switch (m_TypeTrame)
        {
           case TRAME_TX:
            qDebug() << "kill rs tx";
             delete this->m_trame.trame_rs.tx;
            this->m_trame.trame_rs.tx = NULL;
            break;

           case TRAME_RX:
            qDebug() << "kill rs rx";
            delete this->m_trame.trame_rs.rx;
             this->m_trame.trame_rs.rx = NULL;
            break;

        }
        break;
       case Protocole::LIAISON_CAN:
                switch (m_TypeTrame)
                {
                   case TRAME_TX:
                    qDebug() << "kill can tx";
                    delete this->m_trame.trame_can.tx;
                    this->m_trame.trame_can.tx = NULL;
                    break;

                   case TRAME_RX:
                    qDebug() << "kill can rx";
                    delete this->m_trame.trame_can.rx;
                    this->m_trame.trame_can.rx = NULL;
                    break;

                }
           break;
    }
}

//no code in destructor.
tx_rs_device::~tx_rs_device()
{
qDebug() << "delete tx rs";
}
tx_rs_modbus::~tx_rs_modbus()
{
    qDebug() << "delete tx modbus";
    m_TimerTx.stop();
}


thanks

kickoune103

//in main.c, little example, blocking in destructor of tx_rs_device.
//i have created "*tx_modbus" in t_trame_rs (tx_rs_modbus *tx_modbus)
//nothing change.

     l_prot.SetiLiaison(Protocole::LIAISON_RS);
     l_prot.SetIprot(Protocole::PROT_RS_MODBUS);

 Trame *ptTrame = new Trame(&l_prot,"");

 qDebug() << "test delete";
 //ptTrame->setTypeTrame(Trame::TRAME_TX);
 delete ptTrame->getTrame().trame_rs.tx_modbus;
 qDebug() << "test delete";

jsulm

@kickoune103 What is tx in m_trame.trame_can.tx and how is it initialised?

kickoune103

solved..
setParent(this) in the software....

sorry

Pablo J. Rogina

@kickoune103 please don't forget to mark your post as solved. Thanks.