Returns a pointer to Excel's return value
[C++]
static LPCXLOPER RetVal();
This function returns a read-only pointer to some static memory containing a copy of 
            the CXlOper data about to be returned to Excel.
The statement is only valid between a call to CXlOper::Ret() 
			and the return from an add-in function.
			(Note that CXlOper::RetString() and CXlOper::RetError()
			both call CXlOper::Ret(), and therefore use the same buffer.) Thus it is only safe to call it during the destructor of an object which is at function
			scope in an add-in function. 
			It is used by the destructor of CXlCacheBinding to add new results to the cache.
Header: xllplus.h
CXlOper Class 
					  | CXlOper Methods			 
					  | CXlOper::Ret()			 
					  | CXlOper::RetError()			 
					  | CXlOper::RetString()