I am creating a class with custom slots in Qt:

class CustomEdit : public QTextEdit
{
    Q_OBJECT

public:
    CustomEdit(QWidget* parent);

public slots:
    void onTextChanged ();
};

However, I'm getting thise linker error:

undefined reference to 'vtable for CustomEdit'

The documentation says:

if you get compiler errors along the lines of "undefined reference to vtable for LcdNumber", you have probably forgotten to run the moc or to include the moc output in the link command.

... but it is not obvious what that means.

Is there something I need to add to my class, or to the .pro file?