Hi to all,

I have some very strange problems.

I would like to add the Q_OBJECT macro to a class called Plot, inherited by QwtPlot.

I did everything in the right way and if I replace QwtPlot by QObject it works.

If I inherit by QwtPlot I get an "Undefined reference" error by the linker, it complains about missing QMetaObject const QwtPlot::staticMetaObject ...

The .pro file is:
Qt Code: 
  1. #-------------------------------------------------
  2. #
  3. # Project created by QtCreator 2017-03-08T16:00:42
  4. #
  5. #-------------------------------------------------
  6.  
  7. QT       += core gui
  8.  
  9. greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
  10.  
  11. TARGET = Test
  12. TEMPLATE = app
  13.  
  14.  
  15. SOURCES += main.cpp\
  16.         mainwindow.cpp \
  17.     plot.cpp
  18.  
  19. HEADERS  += mainwindow.h \
  20.     plot.h
  21.  
  22. FORMS    += mainwindow.ui
  23.  
  24. INCLUDEPATH += C:\Qwt-6.1.3\include
  25. LIBS += -LC:\Qwt-6.1.3\lib\ -lqwt
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The plot.h is:
Qt Code: 
  1. #ifndef PLOT_H
  2. #define PLOT_H
  3.  
  4. #include <QObject>
  5. #include <qwt_plot.h>
  6.  
  7. class Plot: public QwtPlot
  8. {
  9.     Q_OBJECT
  10. public:
  11.     Plot(QWidget *parent);
  12. };
  13.  
  14. #endif // PLOT_H
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Funny thing is that they do it in pretty much the same way in the examples of Qwt.

Does anyone know how to solve this problem, please?
Thanks a lot.