IBM SC34-7012-01 manual Processing the Ioerr condition, Command Information provided

vSend a message to the terminal operator if, for example, you believe that the abend is due to bad input data.

Information that is available to a program-level exit routine or program includes the following:

Command	Information provided
ADDRESS TWA	The address of the TWA
ASSIGN ABCODE	The current CICS abend code
ASSIGN ABPROGRAM	The name of the failing program for the latest abend
ASSIGN ASRAINTRPT	The instruction length code (ILC) and program interrupt
	code (PIC) data for the latest ASRA or ASRB abend.
ASSIGN ASRAKEY	The execution key at the time of the last ASRA, ASRB,
	AICA, or AEYD abend, if any
ASSIGN ASRAPSW	The PSW for the latest ASRA or ASRB abend
ASSIGN ASRAREGS	The general-purpose registers for the latest ASRA or ASRB
	abend
ASSIGN ASRASPC	The type of space in control at the time of the last ASRA,
	ASRB, AICA, or AEYD abend, if any
ASSIGN ASRASTG	The type of storage being addressed at the time of the last
	ASRA or AEYD abend, if any
ASSIGN ORGABCODE	Original abend code in cases of repeated abends

If an abend occurs during the invocation of a CICS service, issuing a further request for the same service might cause unpredictable results because the reinitialization of pointers and work areas and the freeing of storage areas in the exit routine might not have been completed. In addition, ASPx abends, which are task abends while in syncpoint processing, cannot be handled by an application program.

For transactions that are to be dynamically backed out if an abend occurs, beware of writing exit code that ends with a RETURN command. This would indicate to CICS that the transaction had ended normally and would therefore prevent dynamic transaction backout and automatic transaction restart where applicable.

Exit programs can be coded in any supported language, but exit routines must be in the same language as the program of which they are a part.

See CICS Messages and Codes for the transaction abend codes for abnormal terminations that CICS initiates, their meanings, and the recommended actions.

Programming information relating to the coding of program-level exit code (such as addressability and use of registers) is in the CICS Application Programming Guide. For background information, see the CICS Application Programming Guide.

Processing the IOERR condition

Any program that attempts to process an IOERR condition for a recoverable resource must not issue a RETURN or SYNCPOINT command, but must terminate by issuing an ABEND command. A RETURN or SYNCPOINT command causes the recovery manager to complete the unit of work and commit changes to recoverable resources.

152CICS TS for z/OS 4.1: Recovery and Restart Guide