Progress0 of 0 lessons

CICS HANDLE ABEND - Error Handling and Recovery

The CICS HANDLE ABEND command is a crucial error handling mechanism that allows programs to intercept and manage abnormal termination conditions. It provides a structured approach to error recovery and system stability.

What is CICS HANDLE ABEND?

CICS HANDLE ABEND is a command that establishes an error handling routine to be executed when an abnormal termination (ABEND) occurs in a CICS program. It provides a safety net that allows programs to gracefully handle unexpected errors rather than terminating abruptly.

Command Syntax

cobol
1
2
3
4
5
6
EXEC CICS HANDLE ABEND
    PROGRAM('program-name')
    LABEL(label-name)
    RESP(response-code)
    RESP2(response-code-2)
END-EXEC.

Parameters Explained

PROGRAM Parameter

Specifies the name of the program to be called when an ABEND occurs:

  • Must be a valid CICS program name
  • Program should be designed to handle error conditions
  • Should perform cleanup and recovery operations
  • Must terminate with RETURN or RETURN TRANSID

LABEL Parameter

Specifies a label within the current program to transfer control to:

  • Alternative to PROGRAM parameter
  • Must be a valid label in the current program
  • Provides local error handling capability
  • More efficient than calling external program

RESP Parameters

Response codes returned by the HANDLE ABEND command:

  • RESP: Primary response code
  • RESP2: Secondary response code
  • Always check these codes for command success
  • Handle command failures appropriately

Implementation Examples

Example 1: External Error Handler

cobol
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
WORKING-STORAGE SECTION.
01 WS-RESPONSE           PIC S9(8) COMP.
01 WS-RESPONSE2          PIC S9(8) COMP.
 
PROCEDURE DIVISION.
    EXEC CICS HANDLE ABEND
        PROGRAM('ERROR-HANDLER')
        RESP(WS-RESPONSE)
        RESP2(WS-RESPONSE2)
    END-EXEC.
    
    IF WS-RESPONSE NOT EQUAL DFHRESP(NORMAL)
        EXEC CICS ABEND ABCODE('HABE')
        END-EXEC
    END-IF.
    
    * Main program logic continues here
WORKING-STORAGE SECTION. 01 WS-RESPONSE PIC S9(8) COMP. 01 WS-RESPONSE2 PIC S9(8) COMP. PROCEDURE DIVISION. EXEC CICS HANDLE ABEND PROGRAM('ERROR-HANDLER') RESP(WS-RESPONSE) RESP2(WS-RESPONSE2) END-EXEC. IF WS-RESPONSE NOT EQUAL DFHRESP(NORMAL) EXEC CICS ABEND ABCODE('HABE') END-EXEC END-IF. * Main program logic continues here

Example 2: Local Error Handler

cobol
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
PROCEDURE DIVISION.
    EXEC CICS HANDLE ABEND
        LABEL(ERROR-ROUTINE)
        RESP(WS-RESPONSE)
    END-EXEC.
    
    * Main program logic
    PERFORM PROCESS-DATA
    EXEC CICS RETURN END-EXEC.
    
ERROR-ROUTINE.
    * Error handling logic
    EXEC CICS WRITE OPERATOR
        TEXT('Error occurred in main program')
    END-EXEC.
    
    EXEC CICS RETURN END-EXEC.

Error Handler Program Design

1. Error Information Access

Error handler programs can access ABEND information:

cobol
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
WORKING-STORAGE SECTION.
01 WS-EIB.
    05 WS-EIBTRNID        PIC X(4).
    05 WS-EIBDATE         PIC S9(7) COMP-3.
    05 WS-EIBTIME         PIC S9(7) COMP-3.
    05 WS-EIBRESP         PIC S9(8) COMP.
    05 WS-EIBERRCD        PIC S9(8) COMP.
 
PROCEDURE DIVISION.
    EXEC CICS ASSIGN
        EIBDATE(WS-EIBDATE)
        EIBTIME(WS-EIBTIME)
        EIBRESP(WS-EIBRESP)
        EIBERRCD(WS-EIBERRCD)
    END-EXEC.

2. Cleanup Operations

Error handlers should perform cleanup:

  • Release allocated storage
  • Close open files
  • Release locks
  • Clean up temporary storage
  • Log error information

3. Recovery Actions

Recovery actions may include:

  • Restarting the transaction
  • Redirecting to error page
  • Sending notification messages
  • Attempting alternative processing
  • Graceful termination

Best Practices

1. Early Establishment

Establish error handlers early in program execution:

  • Place HANDLE ABEND at program start
  • Before any risky operations
  • Ensure handler is always active

2. Handler Design

Design error handlers to be:

  • Simple and focused
  • Self-contained
  • Non-recursive
  • Well-tested
  • Properly documented

3. Error Logging

Implement comprehensive error logging:

  • Log ABEND codes and descriptions
  • Record program state information
  • Include user and transaction details
  • Timestamp error occurrences
  • Store in appropriate log files

Common Response Codes

Normal Response Codes

  • NORMAL (0): Command executed successfully
  • HANDLEABEND (8): Handler already established

Error Response Codes

  • INVREQ (16): Invalid request
  • NOTFND (20): Program not found
  • LENGERR (22): Length error
  • OPRIDERR (24): Operator ID error

Handler Stack Management

1. Handler Stack

CICS maintains a stack of error handlers:

  • Multiple handlers can be established
  • Last established handler is active
  • Handlers are popped when programs return
  • Stack is managed automatically

2. Handler Removal

Handlers are automatically removed when:

  • Program returns normally
  • Program terminates
  • New handler is established
  • ABEND occurs and handler executes

Explain It Like I'm 5 Years Old

Imagine you're playing a game with your friends:

Sometimes when you're playing, things go wrong. Maybe you drop your game piece, or someone accidentally knocks over the board. Instead of getting upset and stopping the game, you can have a plan for what to do when things go wrong.

CICS HANDLE ABEND is like having a "what to do when things go wrong" plan for computer programs. Before the program starts doing its work, it tells CICS: "If something bad happens, here's what I want you to do instead of just stopping."

It's like having a backup plan - if your main plan doesn't work, you have another plan ready to go. This way, even when something unexpected happens, the program can still finish what it was supposed to do, just in a different way.

Exercises

Exercise 1: Handler Implementation

Write a CICS HANDLE ABEND command that calls an external error handler program named 'ERRHANDL'. Include proper response code checking.

cobol
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
EXEC CICS HANDLE ABEND
    PROGRAM('ERRHANDL')
    RESP(WS-RESPONSE)
END-EXEC.
 
IF WS-RESPONSE NOT EQUAL DFHRESP(NORMAL)
    EXEC CICS ABEND ABCODE('HABE')
    END-EXEC
END-IF.
EXEC CICS HANDLE ABEND
    PROGRAM('ERRHANDL')
    RESP(WS-RESPONSE)
END-EXEC.
 
IF WS-RESPONSE NOT EQUAL DFHRESP(NORMAL)
    EXEC CICS ABEND ABCODE('HABE')
    END-EXEC
END-IF.

Exercise 2: Error Handler Design

Design an error handler program that logs ABEND information and sends a message to the operator. What CICS commands would you use?

Answer: Use ASSIGN to get error information, WRITE OPERATOR to send messages, and WRITE JOURNAL to log details. Include proper cleanup and termination.

Quiz

Question 1

What is the primary purpose of CICS HANDLE ABEND?

Answer: B) To establish error handling routines

Question 2

Which parameter specifies an external program to handle ABENDs?

Answer: B) PROGRAM

Related Concepts

CICS Error Handling

Comprehensive error handling strategies and techniques in CICS applications

CICS Recovery Procedures

Recovery mechanisms and procedures for handling system failures

CICS Program Design

Best practices for designing robust CICS programs