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CICS ISSUE RECEIVE - Issue Receive

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

What is CICS ISSUE RECEIVE?

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

Command Syntax

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EXEC CICS ISSUE RECEIVE
    [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 receive 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

Receive Types

1. Basic Receives

  • Basic receives: Standard receive operations that handle simple data transfer without special formatting
  • Mapped receives: Receive operations that use predefined field mappings to structure incoming data
  • Unmapped receives: Raw receive operations that handle unstructured data without predefined field mappings
  • Custom receives: Specialized receive operations designed for specific application requirements

2. Advanced Receives

  • Advanced receives: Complex receive operations that handle sophisticated data processing and validation
  • Secure receives: Receive operations that include encryption and security features for sensitive data
  • Encrypted receives: Receive operations that automatically decrypt incoming encrypted data
  • Compressed receives: Receive operations that handle compressed data streams and automatically decompress them

3. Specialized Receives

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

Implementation Example

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WORKING-STORAGE SECTION.
01 WS-RESPONSE            PIC S9(8) COMP.
01 WS-RESPONSE2           PIC S9(8) COMP.
 
PROCEDURE DIVISION.
    * Issue receive
    EXEC CICS ISSUE RECEIVE
        RESP(WS-RESPONSE)
        RESP2(WS-RESPONSE2)
    END-EXEC.
    
    IF WS-RESPONSE NOT EQUAL DFHRESP(NORMAL)
        EXEC CICS WRITE OPERATOR
            TEXT('ISSUE RECEIVE command failed')
        END-EXEC
        EXEC CICS RETURN END-EXEC
    END-IF.
    
    * Receive issued successfully
    * Continue processing

Receive Processing

1. Receive Preparation

Receive preparation includes:

  • Receive validation - ensuring the receive operation is properly configured and authorized
  • Receive formatting - preparing data structures and buffers for incoming data
  • Receive encoding - setting up proper character encoding and data transformation
  • Receive processing - initializing the receive operation and preparing for data transfer

2. Receive Transmission

Receive transmission includes:

  • Receive routing - directing incoming data to the appropriate processing location
  • Receive delivery - ensuring data reaches the correct destination within the application
  • Transmission confirmation - verifying that data was received successfully and completely
  • 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 received data for presentation or further processing
  • User experience - ensuring smooth data flow and responsive application behavior
  • Performance optimization - maximizing receive efficiency and minimizing resource usage

Common Response Codes

Success Response Codes

  • NORMAL (0): Receive issued successfully - data was received without errors
  • RECEIVE (4): Receive issued - operation completed with receive-specific status

Error Response Codes

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

Best Practices

1. Receive Preparation

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

2. Error Handling

  • Check all response codes - always examine both RESP and RESP2 for complete error information
  • Handle receive failures - implement appropriate recovery mechanisms for failed receive 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 receive operations - reduce unnecessary receive calls to improve overall performance
  • Use efficient receive 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 receive operations

Explain It Like I'm 5 Years Old

Imagine you're waiting for a letter:

When you want to get a letter, you wait by the mailbox and check if a letter has arrived. If a letter comes, you can read it and do something with the information. If no letter comes, you have to wait longer or check again.

CICS ISSUE RECEIVE is like waiting for a letter. The computer program waits for data to arrive and checks if it has come. If data arrives, the program can read it and do something with it. If no data arrives, the program has to wait longer or check again.

Just like you wait for letters, the computer program waits for data!

Exercises

Exercise 1: Receive Issuance

Write a CICS ISSUE RECEIVE command to issue a receive operation.

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EXEC CICS ISSUE RECEIVE
    RESP(WS-RESPONSE)
    RESP2(WS-RESPONSE2)
END-EXEC.

Exercise 2: Receive Processing

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

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

Quiz

Question 1

What is the primary purpose of CICS ISSUE RECEIVE?

Answer: B) To issue a receive operation

Question 2

Which parameter specifies the response code?

Answer: A) RESP

Related Concepts

CICS Receive Processing

Receive processing and output in CICS

CICS User Management

User management and user interaction in CICS

CICS Output Processing

Output processing and receive display in CICS