Subclassing QThread — undefined reference to vtable

[jmalicke]

I understand that the undefined reference to vtable error means that I have a pure virtual function that must be implemented. I cannot for the life of me find what I am missing to make this class compile.

WaspThread.h

#include <QThread>
 
class WaspThread : public QThread
{
  Q_OBJECT
 
protected:
  void run();
};

#include <QThread>

class WaspThread : public QThread
{
  Q_OBJECT

protected:
  void run();
};

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WaspThread.cpp

#include "WaspThread.h"
 
void WaspThread::run()
{
 
}

#include "WaspThread.h"

void WaspThread::run()
{

}

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project.pro

SOURCES += WaspThread.cpp
HEADERS += WaspThread.h

SOURCES += WaspThread.cpp
HEADERS += WaspThread.h

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I have the header and source files in my project file. I have tried cleaning out my build directory and re-running qmake multiple times.

---

Added after 21 minutes:

I just figured out the problem. I had forgotten to export the WaspThread class so that the executable utilizing the DLL could find WaspThread. It was a silly mistake. I made it because I forgot that in Windows land you need to export everything whereas in Linux you don't.

[anda_skoa]

If you want to detect that when working on Linux you can enable symbol hiding there as well

QMAKE_CFLAGS_HIDESYMS   += -fvisibility=hidden
QMAKE_CXXFLAGS_HIDESYMS += $$QMAKE_CFLAGS_HIDESYMS -fvisibility-inlines-hidden

QMAKE_CFLAGS_HIDESYMS   += -fvisibility=hidden
QMAKE_CXXFLAGS_HIDESYMS += $$QMAKE_CFLAGS_HIDESYMS -fvisibility-inlines-hidden

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Cheers,
_