How to use QThread::exec()

[intensifi]

Does anyone have any experience with this?

The QT 4.1 examples do not make use of this approach, but the Qthread class documentation shows pseudo code that does. I am drawn to this approach because I normally have my client in request/reply mode with a server, but sometimes the server sends data asynchronously on the socket.

Specifically I'd like to see an eaxmple that has the main run() function use QThread:exec() and have member functions for other threads to call to post requests to the server and have the thread receive messages from the server (QTCPSocket signals) , read tyhem correctly, parse them and emit signals for all server messages to anyone that might be listening.

As a side note, how about protecting the socket read and write functions separately as they are really two distinct pipes.

thanks in advance!

[wysota]

But what exactly is your question? QThread::exec() works the same as QCoreApplication::exec(), it starts an event queue processing.

[intensifi]

My question is how to have a QTcpSocket in the thread, use the socket to send requests to a server via methods callable from the GUI thread, have the thread listen for server messages and then create signals the GUI thread can be connected to obtain the server messages.

[Cesar]

Please, see Threaded Fortune Server Example and Fortune Client Example

[wysota]

You don't need a separate thread for that... you can do this all in one thread. If you want to "call" methods of a separate thread from the "main" thread, it involves synchronisation between those two. You can use signals & slots for that and then it is as easy as connecting them and emitting a signal. But remember that it is all an event driven mechanism and two threads don't wait for each other here...

Some small partial example (this is not a Newbie section, so I expect you can fill the rest).

class MyThread : public QThread{
public:
    void run(){ 
        QTcpSocket *sock = new QTcpSocket;
        connect(this, SIGNAL(sendToSocket(...)), sock, SLOT(...)));
        // ...
        exec();
    }
// ...
};
 
MyThread *thr1;
//...
connect(thr1, SIGNAL(messageReceived(...)), this, SLOT(onMessageReceived(...)));
connect(this, SIGNAL(sendToThread(...)), thr1, SIGNAL(SendToSocket(...)));
thr1->start();

class MyThread : public QThread{
public:
    void run(){ 
        QTcpSocket *sock = new QTcpSocket;
        connect(this, SIGNAL(sendToSocket(...)), sock, SLOT(...)));
        // ...
        exec();
    }
// ...
};

MyThread *thr1;
//...
connect(thr1, SIGNAL(messageReceived(...)), this, SLOT(onMessageReceived(...)));
connect(this, SIGNAL(sendToThread(...)), thr1, SIGNAL(SendToSocket(...)));
thr1->start();

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