OFFSET returns an offset value derived from a pointer reference x and
relative to an area y. If x is the null pointer value, the
null offset value is returned.
>>-OFFSET--(--x--,--y--)---------------------------------------><
- x
- Pointer reference. It must identify a generation of a based variable within the area y, or be the null pointer value.
- y
- Area reference.
If x is an element reference, y must be an element variable.