Thread(s) and socket, timer slots

[stephdev1965]

Hi all

I wrote routines in a form using a QTCpSocket and a QTimer
to receive a non stop data stream from a server and write data from buffer in a different file each minute. It worked fine in the dialog form.

So i tried to write a thread class involving a QSocket and a QTimer too.
I would like to run multiple threads without freezing the user interface.
My thread runs well but events are never fired...
The code compiles well, but returns the following messages on execution :

QObject: Cannot create children for a parent that is in a different thread.
Object::connect: No such slot ThreadReception::readStream()
Object::connect: No such slot ThreadReception::displayError(QAbstractSocket::Soc ketError)
QObject: Cannot create children for a parent that is in a different thread.
Object::connect: No such slot ThreadReception::topMinute()

ecc.

class ThreadReception : public QThread
{
   Q_OBJECT
 
public:
 
    ThreadReception(QObject *parent = 0);
    ~ThreadReception();
 
	bool connectSource();
	void unconnectSource();
 
	QMutex threadMutex;
 
   	QTcpSocket *tcpSocket;
	QTimer *timerHorloge;
 
	(...)
 
private:
	void readStream();
	void topMinute();
   	void saveMinuteBuffer();
 
protected:
    void run();
    void attente();
 
};
 
 
void ThreadReception::run()
{
	tcpSocket = new QTcpSocket(this);
	connect(tcpSocket, SIGNAL(readyRead()), this, SLOT(readStream()), Qt::DirectConnection);
	connect(tcpSocket, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(displayError(QAbstractSocket::SocketError)), Qt::DirectConnection);
 
	//initialise un timer
	timerClock = new QTimer(this);
	connect(timerClock, SIGNAL(timeout()), this, SLOT(topSeconde()), Qt::DirectConnection);
	timerHorloge->start(1000);	//1 seconde
 
	exec();
 
}

class ThreadReception : public QThread
{
   Q_OBJECT

public:

    ThreadReception(QObject *parent = 0);
    ~ThreadReception();

	bool connectSource();
	void unconnectSource();
		
	QMutex threadMutex;
	   
   	QTcpSocket *tcpSocket;
	QTimer *timerHorloge;

	(...)

private:
	void readStream();
	void topMinute();
   	void saveMinuteBuffer();

protected:
    void run();
    void attente();

};


void ThreadReception::run()
{
	tcpSocket = new QTcpSocket(this);
	connect(tcpSocket, SIGNAL(readyRead()), this, SLOT(readStream()), Qt::DirectConnection);
	connect(tcpSocket, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(displayError(QAbstractSocket::SocketError)), Qt::DirectConnection);
	
	//initialise un timer
	timerClock = new QTimer(this);
	connect(timerClock, SIGNAL(timeout()), this, SLOT(topSeconde()), Qt::DirectConnection);
	timerHorloge->start(1000);	//1 seconde
	
	exec();

}

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i modified my code as below. first messages relative to the "parent thread" have disappeared but now i get the following messages

QObject::connect: Cannot connect QTcpSocket::readyRead() to (null)::readStream()
QObject::connect: Cannot connect QTcpSocket::error(QAbstractSocket::SocketError) to (null)::displayError(QAbstractSocket::SocketError)
QObject::connect: Cannot connect QTimer::timeout() to (null)::topMinute()

void ThreadReception::run()
{
	tcpSocket = new QTcpSocket(0);
	connect(tcpSocket, SIGNAL(readyRead()), 0, SLOT(readStream()), Qt::DirectConnection);
	connect(tcpSocket, SIGNAL(error(QAbstractSocket::SocketError)), 0, SLOT(displayError(QAbstractSocket::SocketError)), Qt::DirectConnection);
 
	//initialise un timer
	timerClock = new QTimer(0);
	connect(timerClock, SIGNAL(timeout()), 0, SLOT(topSeconde()), Qt::DirectConnection);
	timerHorloge->start(1000);	//1 seconde
 
	exec();
 
}

void ThreadReception::run()
{
	tcpSocket = new QTcpSocket(0);
	connect(tcpSocket, SIGNAL(readyRead()), 0, SLOT(readStream()), Qt::DirectConnection);
	connect(tcpSocket, SIGNAL(error(QAbstractSocket::SocketError)), 0, SLOT(displayError(QAbstractSocket::SocketError)), Qt::DirectConnection);
	
	//initialise un timer
	timerClock = new QTimer(0);
	connect(timerClock, SIGNAL(timeout()), 0, SLOT(topSeconde()), Qt::DirectConnection);
	timerHorloge->start(1000);	//1 seconde
	
	exec();

}

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What is wrong ? Has someone any idea ?

Best regards

[jpn]

What is wrong ? Has someone any idea ?

The problem is exactly what the error states. "Cannot connect something to null". You are passing "0" as receiver in the connect statements. Here's a thread worth reading.