CreateInstanceFromDll

HINSTANCE CreateInstanceFromDll(LPCTSTR lpDllName, REFCLSID rclsid, REFIID riid, LPVOID * ppv)
{
 (*ppv) = NULL;

 HINSTANCE hDll = LoadLibrary( lpDllName );
 if ( NULL == hDll )
 {
  return NULL;
 }

 typedef HRESULT (__stdcall *GETCLASS_PROC)(REFCLSID,REFIID,LPVOID*);

 GETCLASS_PROC procGetClassObject = (GETCLASS_PROC)GetProcAddress( hDll, "DllGetClassObject" );

 if( procGetClassObject )
 {
  IClassFactory* pFactory = NULL;

  HRESULT hr = procGetClassObject(rclsid, IID_IClassFactory, (void**)&pFactory);
  if( pFactory )
  {
   hr = pFactory->CreateInstance( NULL, riid, ppv);

   pFactory->Release();
   pFactory = NULL;

   if( NULL == *ppv )
   {
    FreeLibrary( hDll );
    return NULL;
   }
  }
  else
  {
   FreeLibrary( hDll );
   return NULL;
  }
 }
 else
 {
  FreeLibrary( hDll );
  return NULL;
 }

 return hDll;
}