I have been told that when a CALLNAT is used, only the addresses of the parameters or PDAs are passed, and when a FETCH is used with parameters, the actual data is passed. Is this true?
This is correct. Data passed in FETCH is put on Natural’s stack and read via an INPUT stmt.
Btw - in CALLNAT you also have the option to have data passed and not just the addresses. But I believe this is not what you want?