Thanks.
Actually I managed to find another solution that works, which is using an empty variant array and calling DimPLSQLValue with the maximum size greater than zero.
However, I have another question. I have a stored function that returns an OUT parameter that is a nested table. Can I call the function without having to define the maximum size of the return value using DimPLSQLTable?
If I call DimPLSQLValue and set the maximum size for the variable, the result may be truncated if its size exceeds the maximum.