Distributed Systems Network Management (DSNM) Subsystem Interface Development Guide

DSNM Library Services
Distributed Systems Network Management (DSNM) Subsystem Interface Development
Guide—109759 A-89
_PREDECESSOR^LM
_PREDECESSOR^LM
_PREDECESSOR^LM returns the address of the list member placed on the list
immediately before the current list member was added.
prev-list-member returned value
INT .EXT
is the address of the predecessor of the current list member.
list input
is the name of a _LIST.
list-member input
INT .EXT
is a pointer to a current member of list.
Considerations
•
List members are logically ordered. The first (or front or head) member is the
earliest put on the list and the last (or end or tail) member is the latest. Each
member has a successor and a predecessor, the predecessor of the first and the
successor of the last being _NULL.
•
list-member must be a current member of list, or @list-member must be
_NULL. If @list-member is _NULL, the address of the last member of list
is returned.
•
Predecessor list members are not necessarily stored at decreasing memory
addresses. You cannot determine the order of list members by comparing their
addresses.
•
_PREDECESSOR^LM returns _NULL if one of the following is true:
•
list-member is the first member of list.
•
list is empty.
•
An error occurs.
@prev-list-member := _PREDECESSOR^LM ( list
,list-member );