A CXlArray object encapsulates the XLARRAY structure.
This structure is used by the Excel SDK, to pass data containing arrays
of floating-point numbers.
CXlArray versus CXlOper
Both CXlOper and CXlArray can be used to pass floating-point arrays to add-in functions.
We prefer to use CXlOper for two reasons:
Using CXlOper, it is possible for the add-in function to truncate any empty cells.
If you use CXlArray, then all empty cells are filled with zeroes by Excel before
the argument is passed to the add-in function.
This may not be acceptable behaviour.
Using CXlOper, you can return a helpful error message if data is of the wrong type,
e.g. "Expected number in Arg1(278)" for an error in the 278th cell of an array.
Using CXlArray, Excel will merely return "#VALUE!", instead of calling the add-in function,
which is much less helpful to the user, especially if the array is very large.
See also Comparison of CXlOper and CXlArray types.
CXlArray Methods | xllplus.h