Interval control EXEC interface sample exit program: DFH$ICCN

DFH$ICCN is an interval control EXEC interface sample exit program. It is designed to be invoked at the XICEREQ exit.

About DFH$ICCN

DFH$ICCN is for use in a distributed routing environment, where you want to cancel a previously-issued interval control request but have no way of knowing to which region to direct the CANCEL. For examples of situations with which DFH$ICCN is designed to cope, see Canceling interval control requests.

DFH$ICCN is invoked before the CANCEL command is executed. It performs the following processing:

  1. Checks:
    1. It has been invoked for a CANCEL command.
    2. The SYSID option was not specified on the command.
    3. The identifier of the request to be canceled does not begin with 'DF'. ('DF' indicates a request issued internally by CICS.)
    4. The name of the transaction that issued the CANCEL command does not begin with 'C'—that is, that the transaction is not a CICS internal transaction, nor a CICS-supplied transaction such as CECI.

    If one or more of these conditions are not met—for example, if it was invoked for a RETRIEVE command—DFH$ICCN does nothing and returns.

  2. Instructs CICSPlex® SM to:
    1. Search every CICS region that it knows about for an interval control request with the identifier (REQID) specified on the CANCEL command.
    2. On each region, cancel the first request (with the specified identifier) that it finds.
      Notes:
      • Requests might be canceled on more than one region.
      • If a particular region contains more than one request with the specified identifier, only the first request found by CICSPlex SM is canceled.
      • You must ensure that CICSPlex SM has UPDATE access to the transaction ID of the transaction associated with the CANCEL request.