Qt moveToThread() vs calling new thread when do we use each

Aditya P picture Aditya P · Mar 1, 2011 · Viewed 15.5k times · Source

When do we use each of this function calls in a threaded application. given two functions fun1() and fun2() defined in the same class dealing with read/write of data into buffers(queue operation). to achieve multi-threading to these. we would have to run the two functions in a separate thread. now lets say the first function read is called at the start of its thread.

is it better to use moveTothread ( second thread)for function write at the start of the first functions thread

Or

define the second function in a new thread class and call that thread at the start of the first thread.

Answer

Kurt Pattyn picture Kurt Pattyn · Mar 1, 2011

Like Piotr answered you should really have a look at the link he suggested.
As I understand your problem, that should solve your problem.
This is the simplified code from that blog:

class Producer  
{  
public:
    Producer();  

public slots:
    void produce()
    { //do whatever to retrieve the data
      //and then emit a produced signal with the data
      emit produced(data);
      //if no more data, emit a finished signal
      emit finished();
    }

signals:
    void produced(QByteArray *data);
    void finished();
};

class Consumer
{
public:
    Consumer();

public slots:
    void consume(QByteArray *data)
    {
       //process that data
       //when finished processing emit a consumed signal
       emit consumed();
       //if no data left in queue emit finished
       emit finished();
    }
};

int main(...)
{
    QCoreApplication app(...);

    Producer producer;
    Consumer consumer;

    producer.connect(&consumer, SIGNAL(consumed()), SLOT(produce()));
    consumer.connect(&producer, SIGNAL(produced(QByteArray *)), SLOT(consume(QByteArray *));

    QThread producerThread;
    QThread consumerThread;
    producer.moveToThread(&producerThread);
    consumer.moveToThread(&consumerThread);

    //when producer thread is started, start to produce
    producer.connect(&producerThread, SIGNAL(started()), SLOT(produce()));

    //when consumer and producer are finished, stop the threads
    consumerThread.connect(&consumer, SIGNAL(finished()), SLOT(quit()));
    producerThread.connect(&producer, SIGNAL(finished()), SLOT(quit()));

    producerThread.start();
    consumerThread.start();

    return app.exec();
}