Call this method to add an IUnknown pointer to the array.
DWORD Add( 
   IUnknown* pUnk  
);
Parameters
- pUnk
Call this method to add an IUnknown pointer to the array. 
Return Value
Returns the cookie associated with the newly added pointer, or 0 if the array is not large enough to contain the new pointer.
Requirements
Header: atlcom.h