how to get the pointer to parent widget/object?

[Lykurg]

In this case it is not possible, because I have already included the definition of class "Plot" into the header file of class "mainFrame", so that I cannot include the definition of class "mainFrame" into the header or cpp file of class "Plot"

You can use a forward declaration!

class mainFrame;
 
class Plot
{
  public:
    Plot(mainFrame *mf = 0);
//...
};

class mainFrame;

class Plot
{
  public:
    Plot(mainFrame *mf = 0);
//...
};

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[rambo83]

Yes, you are right, Lykurg!

I have just found something about forward declaration in Google and used it in my code and it works now! Thank you very much.

best regards,

Vitali