findChildren<QwtPlot *>()

Hi, I want to find all the QwtPlot widgets in my ui. I (a newbie) am currently translating some Python/PyQt code that works well into C++/Qt code. In the Python version these two lines work:

self.combo_list = self.ui.tabs.findChildren(QtGui.QComboBox)
self.plot_list = self.ui.tabs.findChildren(Qwt.QwtPlot)

In C++ this works:

QList<QComboBox *> combo_list = findChildren<QComboBox *>();

but this doesn't:

QList<QwtPlot *> plot_list = findChildren<QwtPlot *>();

and neither does:

QwtPlot *qwp = qFindChild<QwtPlot *>(this, "qwtPlot_DC_LIFETIME");

both giving this error:

unresolved external symbol "public: static struct QMetaObject const QwtPlot::staticMetaObject" ...

This works:

QwtPlot *qwp = (QwtPlot *)qFindChild<QObject *>(this, "qwtPlot_DC_LIFETIME");

but I don't want to have to specify the names of all my QwtPlot objects.

Since what I want to do is possible in PyQt, I'm assuming that I just need to tweak my C++ code.