A MONITOR_SUBLIST request allows you to start (ACTION=START) or stop (ACTION=STOP) monitoring a designated sublist within the list structure. The sublist is identified by list number (LISTNUM) and entry key (ENTRYKEY). To accomplish sublist monitoring, you must specify when you connect to the list structure that you have a local vector associated with your connection to the structure (VECTORLEN keyword) and that the structure supports keyed entries (REFOPTION=KEY).

While sublist monitoring is in effect, the system will queue or withdraw event monitor controls (EMCs) on your event queue to indicate the empty or nonempty state of the sublist. Use sublist monitoring in conjunction with event queue monitoring to process state transitions for monitored sublists.

A MONITOR_SUBLIST request can be issued only for keyed list structures allocated in a coupling facility of CFLEVEL=3 or higher. MONITOR_SUBLIST requests issued for a list structure allocated in a coupling facility of CFLEVEL=0, 1, or 2 will fail.