C++ (Qt)
QFileDialog::QFileDialog(QWidget *parent,
                     const QString &caption,
                     const QString &directory,
                     const QString &filter)
    : QDialog(*new QFileDialogPrivate, parent, 0)
{
    Q_D(QFileDialog);
    d->init(directory, filter, caption);
}
 

C++ (Qt)
int QDialog::exec()
{
// ...
 
(void) eventLoop.exec();
 
/// ............
}
 

C++ (Qt)
while (!d->exit)
            processEvents(flags | WaitForMoreEvents | ProcessEventsFlag(QEventLoop::DeferredDeletion));
 

C++ (Qt)
int QEventLoop::exec(ProcessEventsFlags flags)
{
Q_D(QEventLoop);
    if (d->threadData->quitNow)
        return -1;
 
    if (d->inExec) {
        qWarning("QEventLoop::exec: instance %p has already called exec()", this);
        return -1;
    }
    d->inExec = true;
    d->exit = false;
    d->threadData->eventLoops.push(this);
 
#if defined(QT_NO_EXCEPTIONS)
    while (!d->exit)
        processEvents(flags | WaitForMoreEvents | ProcessEventsFlag(QEventLoop::DeferredDeletion));
#else
    try {
        while (!d->exit)
            processEvents(flags | WaitForMoreEvents | ProcessEventsFlag(QEventLoop::DeferredDeletion));
    } catch (...) {
        qWarning("Qt has caught an exception thrown from an event handler. Throwing\n"
                 "exceptions from an event handler is not supported in Qt. You must\n"
                 "reimplement QApplication::notify() and catch all exceptions there.\n");
        throw;
    }
#endif
 
    QEventLoop *eventLoop = d->threadData->eventLoops.pop();
    Q_ASSERT_X(eventLoop == this, "QEventLoop::exec()", "internal error");
    Q_UNUSED(eventLoop); // --release warning
 
    d->inExec = false;
 
    return d->returnCode;
}