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main.cpp Example File

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 ** Contact: Qt Software Information (qt-info@nokia.com)
 ** This file is part of the example classes of the Qt Toolkit.
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 #include <QtGui>


 using namespace QtConcurrent;

 const int iterations = 20;

 void spin(int &iteration)
     const int work = 1000 * 1000 * 40;
     volatile int v = 0;
     for (int j = 0; j < work; ++j)

     qDebug() << "iteration" << iteration << "in thread" << QThread::currentThreadId();

 int main(int argc, char **argv)
     QApplication app(argc, argv);

     // Prepare the vector.
     QVector<int> vector;
     for (int i = 0; i < iterations; ++i)

     // Create a progress dialog.
     QProgressDialog dialog;
     dialog.setLabelText(QString("Progressing using %1 thread(s)...").arg(QThread::idealThreadCount()));

     // Create a QFutureWatcher and conncect signals and slots.
     QFutureWatcher<void> futureWatcher;
     QObject::connect(&futureWatcher, SIGNAL(finished()), &dialog, SLOT(reset()));
     QObject::connect(&dialog, SIGNAL(canceled()), &futureWatcher, SLOT(cancel()));
     QObject::connect(&futureWatcher, SIGNAL(progressRangeChanged(int, int)), &dialog, SLOT(setRange(int, int)));
     QObject::connect(&futureWatcher, SIGNAL(progressValueChanged(int)), &dialog, SLOT(setValue(int)));

     // Start the computation.
     futureWatcher.setFuture(QtConcurrent::map(vector, spin));

     // Display the dialog and start the event loop.


     // Query the future to check if was canceled.
     qDebug() << "Canceled?" << futureWatcher.future().isCanceled();


 int main()
         qDebug() << "Qt Concurrent is not yet supported on this platform";


Copyright © 2008 Nokia Trademarks
Qt 4.4.3