VALUE Clause - Format 3 - NULL Value (1) >>-VALUE------+----+--+-NULL--+-------------------------------->< '-IS-' '-NULLS-'
This format assigns an address that is not valid to a pointer data item or a procedure-pointer data item. A value of NULL is an undefined value.
VALUE IS NULL can only be specified for elementary items described implicitly or explicitly as USAGE IS POINTER or USAGE IS PROCEDURE-POINTER.