[Qt-interest] another QEventLoop question

[Joshua Grauman]

Hello all,

I'm trying to figure out how to get a QEventLoop to work properly. I think 
I pretty much undestand it, but I saw this in the Qt code. Could someone 
tell me the point of the guard variable below and why it is being checked 
to see if it is null? Under what case would it be null? Thanks!

Josh

     QEventLoop eventLoop;
     d->eventLoop = &eventLoop;
     QPointer<QDialog> guard = this;
     (void) eventLoop.exec(QEventLoop::DialogExec);
     if (guard.isNull())
         return QDialog::Rejected;
     d->eventLoop = 0;