Hi, Derk

Try some more variants:

DECLARE INTEGER JaargiftReken IN NAdvies INTEGER @, INTEGER @, INTEGER @
DECLARE INTEGER JaargiftReken IN NAdvies INTEGER, INTEGER, INTEGER
DECLARE DOUBLE JaargiftReken IN NAdvies INTEGER @, INTEGER @, INTEGER @
DECLARE DOUBLE JaargiftReken IN NAdvies INTEGER, INTEGER, INTEGER

The interface of Delphi function shows that input parameters will not be changed, so there is no need to pass them by their references.

In the second case (my bet) -- of course, if no error occurs -- most probably you will receive a memory address in return. Read 4 or so consecutive bytes from this address and convert them into appropriate numeric type.

And your FoxPro version is?

* * *
Also try to declare and call this function from VB, might give you a clue.