signal-slot issue, how to create a signal when a Qlist is updated

[rakefet]

Hi,

I am re-posting my question. This time I hope I am more clear.

In my GraphicView I have an event:

void MyGraphicsView::mousePressEvent(QMouseEvent * e)
{
    if (e->buttons().testFlag(Qt::MidButton))
    {
        double rad = 2;
        QPointF pt = mapToScene(e->pos());
        QPen myPen = QPen(Qt::red);
        this->Scene->addEllipse(pt.x()-rad, pt.y()-rad, rad*2.0, rad*2.0,myPen, QBrush(Qt::SolidPattern));
        this->list.append(pt);
    }
}

void MyGraphicsView::mousePressEvent(QMouseEvent * e)
{
    if (e->buttons().testFlag(Qt::MidButton))
    {
        double rad = 2;
        QPointF pt = mapToScene(e->pos());
        QPen myPen = QPen(Qt::red);
        this->Scene->addEllipse(pt.x()-rad, pt.y()-rad, rad*2.0, rad*2.0,myPen, QBrush(Qt::SolidPattern));
        this->list.append(pt);
    }
}

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I want to create a connection between my main window's QLabel and MyGraphicsView::list.append(pt); that every time a new value is added to the list, pt will be printed on QLabel of the main window.
I can create a slot in my main window that will print a string on QLabel but I don't know what will be my signal and how the connection command will be look like.
Basically, I don't know how to create a signal when a list is updated.

I hope I can get help on this matter.

Thank,