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CICS RETRIEVE REATTACH EVENT - Event Reattachment Operations

CICS RETRIEVE REATTACH EVENT provides event reattachment capabilities in CICS environments. It enables programs to retrieve reattachment events, manage event reattachment, and handle event reconnection in CICS applications.

What is CICS RETRIEVE REATTACH EVENT?

CICS RETRIEVE REATTACH EVENT is a command that allows programs to retrieve reattachment events, manage event reattachment, and handle event reconnection in CICS environments. It provides event reattachment capabilities, reconnection management, and event handling for CICS applications.

Command Syntax

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EXEC CICS RETRIEVE REATTACH EVENT
    [EVENTID(event-id)]
    [INTO(data-area)]
    [LENGTH(data-length)]
    [RESP(response-code)]
END-EXEC

Parameters

Optional Parameters

  • EVENTID - Event identifier to retrieve reattachment information
  • INTO - Data area to receive reattachment event information
  • LENGTH - Length of data to retrieve
  • RESP - Response code variable

Event Reattachment Types

Connection Reattachment

Reattach to existing connections

  • • SESSION REATTACHMENT - Reattach to existing session connections and restore session state
  • • CONVERSATION REATTACHMENT - Reattach to existing conversation connections and restore conversation state
  • • CHANNEL REATTACHMENT - Reattach to existing channel connections and restore channel state
  • • PROCESS REATTACHMENT - Reattach to existing process connections and restore process state

State Reattachment

Reattach to previous states

  • • TRANSACTION STATE REATTACHMENT - Reattach to previous transaction states and restore transaction context
  • • PROGRAM STATE REATTACHMENT - Reattach to previous program states and restore program context
  • • DATA STATE REATTACHMENT - Reattach to previous data states and restore data context
  • • CONTEXT STATE REATTACHMENT - Reattach to previous context states and restore execution context

Resource Reattachment

Reattach to existing resources

  • • FILE REATTACHMENT - Reattach to existing file resources and restore file access
  • • QUEUE REATTACHMENT - Reattach to existing queue resources and restore queue access
  • • STORAGE REATTACHMENT - Reattach to existing storage resources and restore storage access
  • • DEVICE REATTACHMENT - Reattach to existing device resources and restore device access

Event Reattachment

Reattach to event processing

  • • EVENT HANDLER REATTACHMENT - Reattach to existing event handlers and restore handler state
  • • EVENT PROCESSING REATTACHMENT - Reattach to event processing and restore processing state
  • • EVENT MONITORING REATTACHMENT - Reattach to event monitoring and restore monitoring state
  • • EVENT NOTIFICATION REATTACHMENT - Reattach to event notifications and restore notification state

Programming Examples

Basic Event Reattachment

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. RETRIEVE01.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  EVENT-ID         PIC X(8) VALUE 'EVT001'.
       01  DATA-AREA        PIC X(1000).
       01  DATA-LENGTH      PIC S9(8) COMP.
       01  RESPONSE-CODE    PIC S9(8) COMP.
       
       PROCEDURE DIVISION.
           EXEC CICS RETRIEVE REATTACH EVENT
               EVENTID(EVENT-ID)
               INTO(DATA-AREA)
               LENGTH(DATA-LENGTH)
               RESP(RESPONSE-CODE)
           END-EXEC
           
           IF RESPONSE-CODE = DFHRESP(NORMAL)
               DISPLAY 'Event reattachment retrieved successfully'
               DISPLAY 'Event ID: ' EVENT-ID
               DISPLAY 'Data length: ' DATA-LENGTH
           ELSE
               DISPLAY 'Failed to retrieve event reattachment'
           END-IF
           
           EXEC CICS RETURN END-EXEC.

Event Reattachment Processing

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. RETRIEVE02.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  EVENT-ID         PIC X(8) VALUE 'EVT002'.
       01  DATA-AREA        PIC X(1000).
       01  DATA-LENGTH      PIC S9(8) COMP.
       01  RESPONSE-CODE    PIC S9(8) COMP.
       01  REATTACH-STATUS  PIC X(10).
       
       PROCEDURE DIVISION.
           EXEC CICS RETRIEVE REATTACH EVENT
               EVENTID(EVENT-ID)
               INTO(DATA-AREA)
               LENGTH(DATA-LENGTH)
               RESP(RESPONSE-CODE)
           END-EXEC
           
           IF RESPONSE-CODE = DFHRESP(NORMAL)
               MOVE DATA-AREA(1:10) TO REATTACH-STATUS
               DISPLAY 'Reattachment Status: ' REATTACH-STATUS
               
               EVALUATE REATTACH-STATUS
                   WHEN 'SUCCESS'
                       DISPLAY 'Event reattachment successful'
                   WHEN 'PENDING'
                       DISPLAY 'Event reattachment pending'
                   WHEN 'FAILED'
                       DISPLAY 'Event reattachment failed'
                   WHEN 'TIMEOUT'
                       DISPLAY 'Event reattachment timeout'
                   WHEN OTHER
                       DISPLAY 'Unknown reattachment status'
               END-EVALUATE
           ELSE
               DISPLAY 'Failed to process event reattachment'
           END-IF
           
           EXEC CICS RETURN END-EXEC.

Error Handling with Event Reattachment

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. RETRIEVE03.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  EVENT-ID         PIC X(8) VALUE 'EVT003'.
       01  DATA-AREA        PIC X(1000).
       01  DATA-LENGTH      PIC S9(8) COMP.
       01  RESPONSE-CODE    PIC S9(8) COMP.
       
       PROCEDURE DIVISION.
           EXEC CICS RETRIEVE REATTACH EVENT
               EVENTID(EVENT-ID)
               INTO(DATA-AREA)
               LENGTH(DATA-LENGTH)
               RESP(RESPONSE-CODE)
           END-EXEC
           
           EVALUATE RESPONSE-CODE
               WHEN DFHRESP(NORMAL)
                   DISPLAY 'Event reattachment retrieved successfully'
                   DISPLAY 'Event ID: ' EVENT-ID
               WHEN DFHRESP(NOTFND)
                   DISPLAY 'Event reattachment not found'
               WHEN DFHRESP(INVREQ)
                   DISPLAY 'Invalid reattachment request'
               WHEN DFHRESP(EVENTERR)
                   DISPLAY 'Event-specific error occurred'
               WHEN DFHRESP(REATTACHERR)
                   DISPLAY 'Reattachment-specific error occurred'
               WHEN OTHER
                   DISPLAY 'Unexpected error occurred'
           END-EVALUATE
           
           EXEC CICS RETURN END-EXEC.

Event Reattachment Management

Reattachment State Management

  • • Reattachment State Tracking - Track the current state of reattachment operations
  • • Reattachment State Maintenance - Maintain reattachment state across operations
  • • Reattachment Context Management - Manage reattachment context and environment
  • • Reattachment Session Management - Manage reattachment session lifecycle

Event Management

  • • Event Data Management - Manage event data during reattachment operations
  • • Event State Management - Manage event state during reattachment operations
  • • Event Metadata Management - Manage event metadata during reattachment operations
  • • Event Access Management - Manage event access during reattachment operations

Connection Management

  • • Connection Restoration - Restore connections during reattachment operations
  • • Connection Validation - Validate connections during reattachment operations
  • • Connection Optimization - Optimize connections after reattachment operations
  • • Connection Monitoring - Monitor connections during reattachment operations

Error Management

  • • Error Detection - Detect errors during reattachment operations
  • • Error Recovery - Recover from reattachment operation errors
  • • Error Reporting - Report reattachment operation errors
  • • Error Prevention - Prevent future reattachment operation errors

Error Handling

Common Response Codes

  • DFHRESP(NORMAL) - Event reattachment retrieved successfully
  • DFHRESP(NOTFND) - Event reattachment not found
  • DFHRESP(INVREQ) - Invalid reattachment request
  • DFHRESP(EVENTERR) - Event-specific error
  • DFHRESP(REATTACHERR) - Reattachment-specific error
  • DFHRESP(AUTHORITYERR) - Authorization error

Performance Considerations

Reattachment Efficiency

  • • Optimize reattachment operations - Use appropriate reattachment methods for different event types
  • • Minimize reattachment overhead - Reduce the computational cost of reattachment operations
  • • Use efficient reattachment patterns - Implement reattachment strategies that minimize resource usage
  • • Monitor reattachment performance - Track the performance impact of reattachment operations

Resource Impact

  • • Monitor resource usage - Track how reattachment operations consume system resources
  • • Optimize resource allocation - Ensure efficient allocation of resources for reattachment
  • • Manage resource cleanup - Properly clean up resources after reattachment operations
  • • Track resource utilization - Monitor the overall resource consumption patterns

Best Practices

Event Reattachment Best Practices

  • • Always check response codes
  • • Use appropriate reattachment parameters
  • • Implement proper error handling
  • • Ensure proper reattachment state management
  • • Validate reattachment operations
  • • Optimize reattachment operations
  • • Clean up resources properly

Explain It Like I'm 5 Years Old

Think of CICS RETRIEVE REATTACH EVENT like reconnecting to a friend:

  • • Friend Name: "Which friend to reconnect with" - The event ID
  • • Reconnect: "Reconnect with the friend" - Retrieve reattachment event
  • • Get Information: "Get information about reconnecting" - Receive reattachment details
  • • Check Status: "See if reconnection worked" - Check reattachment status
  • • Stay Connected: "Stay connected with the friend" - Maintain reattachment

Exercises

Exercise 1: Basic Event Reattachment

Create a program that retrieves event reattachment information using RETRIEVE REATTACH EVENT.

Exercise 2: Event Reattachment Processing

Write a program that processes event reattachment and handles different reattachment statuses.

Exercise 3: Error Handling

Implement comprehensive error handling for event reattachment failures and invalid event IDs.

Related Concepts

Event Management

Managing system events

Event Reattachment

Managing event reattachment

Connection Management

Managing system connections

Event Processing

Processing system events

Error Handling

Managing reattachment errors