Cant override CMemFile::GrowFile

Question

I have a class derived from CMemFile called TempMemFile. I need to but cant override the Growfile method in TempMemFile.

When I hand write the GrowFile method in my derived class (TempMemFile) it is never called and In class view when I Click on my TempMemFile > Properties > Overrides the Growfile and other methods are not listed here. In fact only 3 methods are listed as override-able Assert, Dump & Serialize. MSDN specifically states that this method can be overridden. Am I missing something?

Implementation / Declaration

// TempMemFile.h

class CTempMemFile : public CMemFile

    {

    public:
        CTempMemFile(void);
        ~CTempMemFile(void);
        DWORD Begin(void);

    private:      
      void GrowFile(SIZE_T dwNewLen);  // override

    };

// TempMemFile.cpp

CTempMemFile::CTempMemFile(void) : CMemFile

    {   

    }

CTempMemFile::~TempMemFile(void)
    {

    }


void GrowFile(SIZE_T dwNewLen)

{

// This function is never called but CMemFile::Growfile always is verified on the callstack

}

Answer 1

Your GrowFile implementation is for a global function called GrowFile. You need CTempMemFile:: in front of the implementation.

void CTempMemFile::GrowFile(SITE_T dwNewLen)
{
}

Answer 2

Also make sure that the visibility of your override method matches the declaration of the base class:

private:      
  void GrowFile(SIZE_T dwNewLen);  // override

is incorrect

Should be public or protected (whatever CMemFile::GrowFile declares it as).