QTcpSocket - Events

[Skorpien126]

Hi,
i´ve a strange problem. I try to implement some kind of permanent event for an object deriving from QTcpSocket. My first idea was to use a simple timer be called all x-msecs. The problem is that I can´t connect to slots defined in my subclass - I checked out the internet and found this http://stackoverflow.com/questions/1...of-derived-one. All the points of the solution are applied but it´s still not working - any idea why it´s not working?

Furthermore I tried it with the timer of QObject-Baseclass - call startTimer() and implementing timerEvent(QEvent* event) - but the function is never called!??!

Is there a reason for this behaviour - do I miss something?!?!?

[tbscope]

Can you please post your code?
There can be tons of possible errors and without seeing the code it's not easy to pin them down.

[Skorpien126]

Sure.... here a simple example.

#ifndef MYTCPSOCKET_H
#define MYTCPSOCKET_H
 
#include <QDebug>
#include <QHostInfo>
#include <QHostAddress>
#include <QTcpSocket>
#include "Definitions.h"
 
class myTCPSocket: public QTcpSocket
{
  Q_OBJECT
 
  public:
    myTCPSocket(QObject* in_Parent = NULL);
     ~myTCPSocket(void);
 
    // init the object (startTimer)
    void init()
    {
      startTimer();
    }
 
    // reads a package
    bool readPackage(tNetworkTcpData* in_NetworkTcpData);
 
    // writes a package
    bool writePackage(tNetworkTcpData in_NetworkTcpData);
 
    // handle event
    void timerEvent(QTimerEvent *event)
    {
      qDebug()<< "timerEventFired";
    }
 
  private:
};
#endif //MYTCPSOCKET_H

#ifndef MYTCPSOCKET_H
#define MYTCPSOCKET_H

#include <QDebug>
#include <QHostInfo>
#include <QHostAddress>
#include <QTcpSocket>
#include "Definitions.h"

class myTCPSocket: public QTcpSocket
{
  Q_OBJECT

  public:
    myTCPSocket(QObject* in_Parent = NULL);
     ~myTCPSocket(void);

    // init the object (startTimer)
    void init()
    {
      startTimer();
    }

    // reads a package
    bool readPackage(tNetworkTcpData* in_NetworkTcpData);

    // writes a package
    bool writePackage(tNetworkTcpData in_NetworkTcpData);
    
    // handle event
    void timerEvent(QTimerEvent *event)
    {
      qDebug()<< "timerEventFired";
    }

  private:
};
#endif //MYTCPSOCKET_H

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My Socket is initialized like that....

myTCPSocket m_TcpSocket = static_cast<myTCPSocket*>(in_TcpSocket);
m_TcpSocket->init();

Thx for the help..

[tbscope]

Quoting the documentation:

If interval is 0, then the timer event occurs once every time there are no more window system events to process.

So, try setting a real interval and see what happens.

Also:

Note that QTimer's accuracy depends on the underlying operating system and hardware. Most platforms support an accuracy of 20 milliseconds; some provide more. If Qt is unable to deliver the requested number of timer events, it will silently discard some.

It's not a good idea to use timers to receive or send data (at least I don't think so)

[Skorpien126]

Nothing happens at all.... I set the value to 1000 and 5000 milliseconds.

I know that the accuracy depends on the system - but this not the crititcal point in my case - I just want that the events is emitted when the process has to time to handle it. An update every 500msecs would be satisfying for me too.

[numbat]

myTCPSocket m_TcpSocket = static_cast<myTCPSocket*>(in_TcpSocket);

myTCPSocket m_TcpSocket = static_cast<myTCPSocket*>(in_TcpSocket);

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I don't think this works like you think it does. In particular, I think the vtable still points to the QTcpSocket vtable rather than your subclass vtable. In short, you don't want to do this.

[Skorpien126]

Ok... it´s obvisously whats wrong. Thx....
P.S. Everyone with the same problem. I create a normal QTcpSocket now and connecting it. Afterwards I use the socketDescriptor to initialize my myTcpSocket-object. not sure if this the best way - but it works fine for me.