I'm trying to write a wrapper so threaded classes have a common interface--so I can write threaded classes expecting certain available functionality, and I and others can write clients, expecting some common functionality.

So, I wrote an abstract class to act as my "middle man."
Qt Code: 
  1. #ifndef THREADBASE_H
  2. #define THREADBASE_H
  3.  
  4. #include <QThread>
  5.  
  6. class ThreadBase : public QThread
  7. {
  8. public:
  9.     ThreadBase();
  10. signals:
  11.     void progressChanged(int);
  12.     void exceptionOccurred(int);
  13. protected:
  14.     void run();
  15.     virtual void runThread() = 0;
  16. };
  17.  
  18. ThreadBase::ThreadBase() : QThread(0)
  19. {
  20. }
  21.  
  22. void ThreadBase::run()
  23. {
  24.     runThread();
  25. }
  26.  
  27. #endif // THREADBASE_H
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This compiled fine. I then tried writing a derived class.
Qt Code: 
  1. // testsubclass.h
  2. #ifndef TESTSUBCLASS_H
  3. #define TESTSUBCLASS_H
  4.  
  5. #include "threadbase.h"
  6.  
  7. class TestSubClass : public ThreadBase
  8. {
  9. public:
  10.     TestSubClass();
  11. protected:
  12.     void runThread();
  13. };
  14.  
  15. #endif // TESTSUBCLASS_H
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Qt Code: 
  1. // testsubclass.cpp
  2. #include "testsubclass.h"
  3.  
  4. TestSubClass::TestSubClass() : ThreadBase()
  5. {
  6. }
  7.  
  8. void TestSubClass::runThread()
  9. {
  10.     for(int i = 0; i < 100; i++)
  11.     {
  12.         emit progressChanged(i);
  13.         wait(100);
  14.     }
  15.     emit progressChanged(100);
  16. }
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I'm receiving a compiler error on lines 12 and 15 in testsubclass.cpp:
Qt Code: 
  1. undefined reference to `ThreadBase::progressChanged(int)'
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I think I'm having a mind-block, because I have done this before in other classes, and it works. As a derived class, shouldn't TestSubClass have access to the public members of ThreadBase? This might be a C++ question, but I didn't know if there were special rules for using signals in abstract classes that I missed.

P.S. I'm in Windows, using MinGW, with gcc version 3.4.5.