Qt - conversion qreal to double

I'm using Ubuntu 11.10, Qt 4, Qwt 6.0.1 the problem is that in general everything works, examples from Qwt compile without ANY problems, but when I try to convert from QPointF.x to double I get error. The funnies thing is that (on x86) qreal is supposed to be redefinition of double... here is what doesn't work ( ``` QPointF pt; pt.setX(1.0); pt.setY(2.0); double px=pt.x; ``` the compiler returns error: ``` error: argument of type ‘qreal (QPointF::)()const {aka double (QPointF::)()const}’ does not match ‘double’ ``` Am I doing something stupid? In short: I need to convert it to use in class inheriting from QwtSeriesData to make custom interpolation between points (in this case it's not gonna be simple linear interpolation). For that I need method ``` double y(double x) const ``` which will return value of function of given x when I simplified it to use QwtSeriesData it compiles. For this to work it was just necessary to implement ``` QPointF sample(size_t i) const size_t size() const ``` but as I said, I need custom interpolation, so seems that implementing interface inheriting from QwtSyntheticPointData is the best option.