🚀 go-pugleaf

Hi all, been having a right nightmare with a callback function that i'm 
trying to code / work with.

I'm using some third-party libraries written in pascal but i have a .h / 
.hpp for them.  I've created a wrapper class to deal with all the aspects of 
using these libraries.  However, one of the functions requires a callback 
procedure.  I need this callback to be able to 'see' my wrapper so i 
declared it thus:

// header
class TInjectController
{
private:
   TCriticalSection *csIPCCallBack;
   static void CALLBACK IPCProcessMsg(char *cName, void *pMsgBuf, unsigned 
int iMsgLen, void *pRtnBuf, unsigned int iRtnLen);
   ...

public:
   ...
   TInjectController();
   ~TInjectController();
};

extern TInjectController *InjectController;

// implimentation
void CALLBACK TInjectController::IPCProcessMsg(char *cName, void *pMsgBuf, 
unsigned int iMsgLen,
                                               void *pRtnBuf, unsigned int 
iRtnLen)
{
   InjectController->csIPCCallBack->Enter();
   ...
   InjectController->csIPCCallBack->Leave();
}

- I've declared the callback function as static and stuck in the extern 
reference at the bottom of the class.  I did this because it's the only way 
that i found that works in the past, with other callbacks i.e. EnumWindows 
etc...

However, on compile i get "[Linker Error] Unresolved external 
'_InjectController' referenced from C:\DOCUMENTS AND 
SETTINGS\ADMINISTRATOR\DESKTOP\TEST 
INJECTOR\TINJECTCONTROLLER\TINJECTCONTROLLER.OBJ"

If i remove the reference to the wrapper from within the callback, it works 
fine - but defeats the object and breaks my design.

Can anyone help me out here?  Also, can anyone tell me why the extern 
reference seems to be necessary >