User Routine Recovery

XCF does not provide any recovery for the message user routine. Routines that require recovery must establish their own. XCF does place sufficient information into the SDWA to identify the message user routine that was in control. The multi-system application must provide whatever diagnostic data is required for problem determination for the message user routine.

If XCF cannot access the parameter list generated by the IXCMSGIX macro, or the parameter list is improperly set, the message user routine's recovery routine will get control provided the message user routine sets up its recovery before invoking IXCMSGIX.

Members that identify a message user routine should allow for SRB-to-task percolation. (Note: SRB-to-task percolation does not work for address space associated members. See Member Association for more information. If XCF processing fails, and XCF does not retry, XCF abnormally ends the task that the member is associated with (either the task or the job step task as specified on IXCJOIN) with a retryable system completion code 00C and one of the following reason codes:

Reason code 02070000 means that XCF successfully delivered the message and the message user returned control to XCF. The task's recovery routine does not have to take any action.
Reason code 02070001 means that XCF did not successfully deliver the message. The task's recovery routine might do one of the following:
- Determine which message, if any, is lost, and notify the sender of the message to send the message again.
- Back up to some logical point and continue processing from that point.
- Allow the task to abnormally end.

To ensure that the member's recovery can intercept SRB-to-task percolation, the task that the member is associated with must ensure that its recovery routine always receives control when a task abnormally ends. To accomplish this, the associated task should issue the WAIT macro and continue waiting indefinitely while other tasks perform the member's work.

SRB-to-task percolation does not occur while the task's recovery routine is running. XCF waits until the task is not in recovery before abnormally ending the task.