The coupling facility storage can contain three types of structures, each of which has its own set of services. To access these services, you must first “connect” to a structure, specifying both a name and a structure type. The name you provide for the structure when you connect is the same name that appears in the active coupling facility resource management (CFRM) policy governing the installation's use of the coupling facility. The IXLCONN macro is the service that allows you to connect to a structure.

When you no longer need access to a coupling facility structure, you can disconnect from the structure. The IXLDISC macro is the service that allows you to disconnect from a structure. In order to access the structure at some later time, you must again connect to the structure using the IXLCONN macro.

Sysplex-wide information about connectors to a structure is made known throughout the sysplex through each connector's exits. The system uses the event exit to notify you about new connections to a structure, disconnections, loss of connectivity or failure of a structure, synchronization points when a structure is being rebuilt, other user-defined synchronization points, and changes in the volatility state of the coupling facility. How you respond to these events depends on the type of event — some events require that you respond through a macro invocation, IXLEERSP, while other events require only that you set a return code in a parameter list that your event exit accesses.

Other structure-specific information is made known to connectors through additional exits, which, if applicable, you specify when you connect to a structure. The complete exit, which applies to all structure types, notifies you when a request that you submitted previously has completed. The notify exit, which applies only to serialized structures — lock and serialized list, may be used when contention for a resource occurs. The contention exit, which applies only to a lock structure, is used to manage resource contention. The list transition exit, which applies only to a list structure using list monitoring, notifies you when a list has changed from an empty to a non-empty state. Each exit type references a parameter list with which you can communicate to the system and to your peer connections. (A peer connection is another user connected to the same structure.)

For planned reconfiguration, recovery, and improved availability and usability, three additional connection services are available — IXLREBLD, IXLUSYNC, and IXLALTER.

The IXLREBLD service can be used to start or stop either type of structure rebuild processing. It also provides the interface for the user-managed protocol. See Structure Rebuild Processing.

IXLUSYNC allows for defining user-defined synchronization points not only in recovery scenarios, but as your application requires.

The IXLALTER service allows you to dynamically change the size of a structure and/or the apportionment of structure storage while connectors continue to use the structure.

For cleanup processing, the IXLFORCE service allows you to delete structure resources in a coupling facility.

IXLPURGE is used to complete outstanding operations against a coupling facility structure.