Undefined reference to vtable

Sorry to bother everyone again with my petty programming knowledge...

When linking a c++ project I get this strange error:

Quote:
"libQtGui.a(qprintdialog_unix.o):(.got2+0x94): undefined reference to `vtable for QUnixPrintWidget'"

The class QUnixPrintWidget (defined in 'qprintdialog.h') looks something like this:

Quote:
"class Q_GUI_EXPORT QUnixPrintWidget : public QWidget
{
Q_OBJECT

public:
QUnixPrintWidget(QPrinter *printer, QWidget *parent = 0);
~QUnixPrintWidget();
void updatePrinter();

private:
friend class QPrintDialogPrivate;
friend class QUnixPrintWidgetPrivate;
QUnixPrintWidgetPrivate *d;
Q_PRIVATE_SLOT(d, void _q_printerChanged(int))
Q_PRIVATE_SLOT(d, void _q_btnBrowseClicked())
Q_PRIVATE_SLOT(d, void _q_btnPropertiesClicked())
};"

The three methods are defined in 'qprintdialog_unix.cpp'.

I know that vtable has something to do with virtual functions, but I have no clue how it actually works. I've read ao. a gcc faq-entry that talks about this, something with "non-pure-virtual" and "out-of-line" virtual functions, but I don't really understand what it says. Can anyone help?

@alfkil

Were you linking with GCC or G++? You have to do the latter if you're using C++ code so that it will link in libstdc++.

@Samurai_Crow

I'm linking with g++.

I just posted on the GCC-help mailing list, hope that'll get me something...

@alfkil

Sorry to have taken your time again! The problem suddenly just vanished when recompiling a larger part of the library (no changes...). Mystery...

wow! interesting port! good luck!