Progress0 of 0 lessons

CICS ISSUE SIGNAL - Issue Signal

CICS ISSUE SIGNAL issues a signal operation, enabling signal management and output processing in CICS environments. It provides efficient signal capabilities for CICS applications.

What is CICS ISSUE SIGNAL?

CICS ISSUE SIGNAL issues a signal operation, enabling signal management and output processing. It provides efficient signal capabilities, allowing applications to issue signal operations.

Command Syntax

cobol
1
2
3
4
EXEC CICS ISSUE SIGNAL
    [RESP(response-code)]
    [RESP2(response-code-2)]
END-EXEC.

Parameters Explained

RESP Parameters

Response codes returned by the command:

  • RESP: Primary response code - indicates the success or failure of the signal operation
  • RESP2: Secondary response code - provides additional error information when RESP indicates failure
  • Always check these codes for command success before proceeding with data processing
  • Handle command failures appropriately to prevent application errors

Signal Types

1. Basic Signals

  • Basic signals: Standard signal operations that handle simple notification without special formatting
  • Mapped signals: Signal operations that use predefined field mappings to structure signal data
  • Unmapped signals: Raw signal operations that handle unstructured signal data without predefined field mappings
  • Custom signals: Specialized signal operations designed for specific application requirements

2. Advanced Signals

  • Advanced signals: Complex signal operations that handle sophisticated notification processing and validation
  • Secure signals: Signal operations that include encryption and security features for sensitive notifications
  • Encrypted signals: Signal operations that automatically encrypt signal data
  • Compressed signals: Signal operations that handle compressed signal streams and automatically compress signal data

3. Specialized Signals

  • Specialized signals: Signal operations tailored for specific protocols or communication methods
  • High-performance signals: Optimized signal operations designed for maximum throughput and efficiency
  • Low-latency signals: Signal operations optimized for minimal delay and real-time processing requirements
  • High-throughput signals: Signal operations designed to handle large volumes of notifications efficiently

Implementation Example

cobol
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
WORKING-STORAGE SECTION.
01 WS-RESPONSE            PIC S9(8) COMP.
01 WS-RESPONSE2           PIC S9(8) COMP.
 
PROCEDURE DIVISION.
    * Issue signal
    EXEC CICS ISSUE SIGNAL
        RESP(WS-RESPONSE)
        RESP2(WS-RESPONSE2)
    END-EXEC.
    
    IF WS-RESPONSE NOT EQUAL DFHRESP(NORMAL)
        EXEC CICS WRITE OPERATOR
            TEXT('ISSUE SIGNAL command failed')
        END-EXEC
        EXEC CICS RETURN END-EXEC
    END-IF.
    
    * Signal issued successfully
    * Continue processing

Signal Processing

1. Signal Preparation

Signal preparation includes:

  • Signal validation - ensuring the signal operation is properly configured and authorized
  • Signal formatting - preparing data structures and buffers for signal data
  • Signal encoding - setting up proper character encoding and data transformation
  • Signal processing - initializing the signal operation and preparing for notification

2. Signal Transmission

Signal transmission includes:

  • Signal routing - directing signal data to the appropriate processing location
  • Signal delivery - ensuring signal data reaches the correct destination within the application
  • Transmission confirmation - verifying that signal was completed successfully
  • Error handling - managing transmission failures and implementing retry mechanisms

3. Output Management

Output management includes:

  • User management - handling user sessions and maintaining connection state
  • Output formatting - structuring signal data for presentation or further processing
  • User experience - ensuring smooth data flow and responsive application behavior
  • Performance optimization - maximizing signal efficiency and minimizing resource usage

Common Response Codes

Success Response Codes

  • NORMAL (0): Signal issued successfully - notification was sent without errors
  • SIGNAL (4): Signal issued - operation completed with signal-specific status

Error Response Codes

  • INVREQ (16): Invalid request - the signal operation parameters are incorrect or unauthorized
  • NOTFND (20): Resource not found - the specified signal resource does not exist
  • LENGERR (22): Length error - the signal data length exceeds expected limits
  • SIGNAL (24): Signal error - a signal-specific error occurred during the operation

Best Practices

1. Signal Preparation

  • Prepare signal appropriately - ensure all necessary resources and configurations are in place
  • Validate signal content - verify that signal data meets expected format and quality standards
  • Handle different signal types - implement flexible processing to accommodate various notification formats
  • Ensure signal integrity - maintain data consistency and prevent corruption during signal transmission

2. Error Handling

  • Check all response codes - always examine both RESP and RESP2 for complete error information
  • Handle signal failures - implement appropriate recovery mechanisms for failed signal operations
  • Implement retry logic - provide automatic retry capabilities for transient failures
  • Log error conditions - maintain detailed logs for troubleshooting and monitoring purposes

3. Performance Optimization

  • Minimize signal operations - reduce unnecessary signal calls to improve overall performance
  • Use efficient signal formats - choose appropriate data formats to minimize processing overhead
  • Optimize user updates - streamline user interface updates to reduce response time
  • Manage user resources - efficiently allocate and manage system resources for signal operations

Explain It Like I'm 5 Years Old

Imagine you're ringing a bell:

When you want to tell everyone something important, you ring a bell and everyone listens. If the bell rings loud enough, everyone can hear it. If the bell doesn't ring, you have to try again.

CICS ISSUE SIGNAL is like ringing a bell. The computer program rings a signal and everyone listens. If the signal is sent loud enough, everyone can hear it. If the signal isn't sent, the program has to try again.

Just like you ring bells to tell people things, the computer program sends signals to tell other programs things!

Exercises

Exercise 1: Signal Issuance

Write a CICS ISSUE SIGNAL command to issue a signal operation.

cobol
1
2
3
4
EXEC CICS ISSUE SIGNAL
    RESP(WS-RESPONSE)
    RESP2(WS-RESPONSE2)
END-EXEC.

Exercise 2: Signal Processing

How would you implement comprehensive signal processing that handles different signal types and requirements?

Answer: Identify different signal types and appropriate handling, implement signal validation and encoding, handle different signal types and capabilities, implement proper error handling for signal failures, optimize signal operations for performance, and maintain signal integrity throughout the process.

Quiz

Question 1

What is the primary purpose of CICS ISSUE SIGNAL?

Answer: B) To issue a signal operation

Question 2

Which parameter specifies the response code?

Answer: A) RESP

Related Concepts

CICS Signal Processing

Signal processing and output in CICS

CICS User Management

User management and user interaction in CICS

CICS Output Processing

Output processing and signal display in CICS