class Watcher : public QObject{
    Q_OBJECT
public:
    Watcher(QObject *parent = 0):
        QObject(parent)
    {
        foreach(QObject *child, parent->children()){
            connect(child, SIGNAL(destroyed(QObject*)),
                    this, SLOT(_destroyed(QObject*)));
        }
    }
private slots:
    void _destroyed(QObject *object){
        qDebug() << object << " destroyed";
    }
};