The NACT04 program is a general-purpose error routine. It isn’t invoked directly by any transaction, but instead receives control from programs NACT01, NACT02, and NACT03 when they meet a condition from which they cannot recover.
The program sends a screen to the terminal user (see Figure 5-2) with a text description of the problem and a request to report it. The text is based on the CICS command that failed and the particular error that occurred on it. The name of the transaction and the program (and, if applicable, the file) involved are also shown. The command, error type, and program name are passed to the NACT04 program from the program that transferred control to it; other items come from the CICS EXEC Interface Block (EIB). The EIB is a CICS control block associated with a task, containing information accessible to the application program. We’ll look at it in more detail in The EXEC Interface Block (EIB) in Chapter 11.
After writing the screen, the program abends, so that any updates to recoverable resources performed in the half-completed transaction get backed out.
You’ll see the NACT04 program in action in the Execution Diagnostic Facility (EDF) session described in Chapter 16.
Figure 5-2. An example of a transaction error screen
As you saw in Figure 4-3, the NACT04 program begins by issuing an EXEC CICS ASSIGN command. This command obtains information from CICS ...