COBOL Tutorial

COBOL DEBUG-CONTENTS Clause - Quick Reference

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Overview

The DEBUG-CONTENTS clause is used to define debugging data items that track the actual contents or values of data items during program debugging. This clause is part of COBOL's debugging facility and provides essential content tracking for detailed data analysis and debugging.

Purpose and Usage

Content tracking - Track actual values of data items
Data monitoring - Monitor data contents during execution
Value analysis - Analyze data values and transformations
Data flow tracking - Track data flow through program
Development support - Aid in detailed data debugging

Content Tracking Concept

Data Flow: [Variable A = 100] → [Variable B = "Hello"] → [Variable C = 2023-12-25]

DEBUG-CONTENTS: [Current Data Value/Content]

Debugging Info: [Variable A: Value = 100, Type = Numeric]

Tracks actual contents and values of data items

DEBUG-CONTENTS provides real-time tracking of data item contents and values.

Syntax

The DEBUG-CONTENTS clause follows specific syntax patterns and is typically used at the 77 level for independent debugging data items.

Basic Syntax

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* Basic DEBUG-CONTENTS clause syntax
77 debug-contents-item DEBUG-CONTENTS.
 
* Examples
77 DEBUG-DATA-CONTENTS DEBUG-CONTENTS.
77 DEBUG-VALUE-CONTENTS DEBUG-CONTENTS.
77 DEBUG-VAR-CONTENTS DEBUG-CONTENTS.
 
* Complete example with data description
77 DEBUG-DATA-CONTENTS DEBUG-CONTENTS PIC X(100).
77 DEBUG-VALUE-CONTENTS DEBUG-CONTENTS PIC X(200).
77 DEBUG-VAR-CONTENTS DEBUG-CONTENTS PIC X(150).
 
* Usage in program
PROCEDURE DIVISION.
    * Display current data contents
    DISPLAY "Data contents: " DEBUG-DATA-CONTENTS
    
    * Store contents for later use
    MOVE DEBUG-DATA-CONTENTS TO SAVED-CONTENTS
    
    * Check if contents match expected value
    IF DEBUG-DATA-CONTENTS = "Expected Value"
        DISPLAY "Contents match expected value"
    END-IF

DEBUG-CONTENTS is typically used at the 77 level for independent debugging items.

Data Type Considerations

Data Type	Size	Use Case
PIC X(50)	50 characters	Short content displays
PIC X(100)	100 characters	Standard content displays
PIC X(200)	200 characters	Long content displays
PIC X(500)	500 characters	Very long content displays

Debugging Mode Requirements

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* Enabling debugging mode for DEBUG-CONTENTS
* Compiler option
* Example: cobc -fdebug program.cob
 
* Runtime debugging activation
* Set environment variable
* Example: COBOL_DEBUG=1 ./program
 
* Program-level debugging declaration
PROGRAM-ID. DEBUG-PROGRAM.
ENVIRONMENT DIVISION.
CONFIGURATION SECTION.
SPECIAL-NAMES.
    DEBUGGING MODE IS ON.
 
DATA DIVISION.
WORKING-STORAGE SECTION.
77 DEBUG-DATA-CONTENTS DEBUG-CONTENTS PIC X(100).

DEBUG-CONTENTS requires debugging mode to be enabled for content tracking functionality.

Common Use Cases

DEBUG-CONTENTS is commonly used in specific debugging scenarios where detailed content tracking is needed for data analysis.

Data Value Tracking

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* Tracking data values during processing
77 DEBUG-DATA-CONTENTS DEBUG-CONTENTS PIC X(100).
 
PROCEDURE DIVISION.
    DISPLAY "Starting data processing with contents: " DEBUG-DATA-CONTENTS
    
    * Process customer data
    MOVE "John Doe" TO CUSTOMER-NAME
    DISPLAY "Customer name contents: " DEBUG-DATA-CONTENTS
    
    MOVE 1000 TO CUSTOMER-BALANCE
    DISPLAY "Customer balance contents: " DEBUG-DATA-CONTENTS
    
    MOVE "2023-12-25" TO TRANSACTION-DATE
    DISPLAY "Transaction date contents: " DEBUG-DATA-CONTENTS
    
    DISPLAY "Data processing completed with contents: " DEBUG-DATA-CONTENTS

Track actual values of data items during processing.

Data Transformation Monitoring

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* Monitoring data transformations
77 DEBUG-DATA-CONTENTS DEBUG-CONTENTS PIC X(100).
 
PROCEDURE DIVISION.
    * Monitor data before transformation
    DISPLAY "Before transformation: " DEBUG-DATA-CONTENTS
    
    * Perform data transformation
    COMPUTE TRANSFORMED-VALUE = ORIGINAL-VALUE * 1.1
    DISPLAY "After transformation: " DEBUG-DATA-CONTENTS
    
    * Monitor data validation
    IF TRANSFORMED-VALUE > 1000
        DISPLAY "High value detected: " DEBUG-DATA-CONTENTS
    END-IF
    
    * Monitor data formatting
    MOVE FUNCTION FORMATTED-DATE(TRANSACTION-DATE) TO FORMATTED-DATE
    DISPLAY "Formatted date: " DEBUG-DATA-CONTENTS

Monitor data transformations and formatting operations.

Conditional Content Debugging

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* Conditional debugging based on contents
77 DEBUG-DATA-CONTENTS DEBUG-CONTENTS PIC X(100).
 
PROCEDURE DIVISION.
    * Only show debugging info for specific content patterns
    IF DEBUG-DATA-CONTENTS CONTAINS "ERROR"
        DISPLAY "Error content detected: " DEBUG-DATA-CONTENTS
        * Add error handling logic here
    END-IF
    
    * Break execution at specific content
    IF DEBUG-DATA-CONTENTS = "CRITICAL_VALUE"
        DISPLAY "Critical content reached: " DEBUG-DATA-CONTENTS
        * Add breakpoint logic here
    END-IF
    
    * Track content frequency
    IF DEBUG-DATA-CONTENTS = "FREQUENT_VALUE"
        ADD 1 TO CONTENT-COUNT
        DISPLAY "Frequent content detected " CONTENT-COUNT " times"
    END-IF

Use content patterns to implement conditional debugging logic.

Best Practices and Tips

Following these best practices ensures effective use of the DEBUG-CONTENTS clause for content debugging and data analysis.

DEBUG-CONTENTS Design Principles

Choose appropriate size - Select data type that accommodates your longest content
Use meaningful names - Choose descriptive names for debugging content items
Minimize overhead - Don\'t overuse content tracking to avoid performance impact
Document content patterns - Document expected content patterns for validation
Consider production impact - Remember that content tracking can affect performance
Test debugging functionality - Verify that content tracking works correctly

Common Pitfalls to Avoid

Pitfall	Problem	Solution
Insufficient field size	Content truncated	Choose appropriate PIC size for longest content
Overuse in production	Performance degradation	Use conditional compilation or separate versions
Not enabling debug mode	No content tracking information	Ensure debugging mode is properly enabled
Poor naming conventions	Confusing debugging output	Use clear, descriptive names
Not documenting usage	Difficult to understand content tracking	Document all content tracking items and their purpose

Performance Considerations

Content tracking overhead - DEBUG-CONTENTS adds runtime overhead when active
Memory usage - Content tracking items consume additional memory
I/O impact - Content tracking output may affect I/O performance
Production considerations - Disable content tracking in production environments
Selective tracking - Use conditional logic for selective content tracking
Debugging levels - Consider different levels of content tracking detail

When to Use DEBUG-CONTENTS

Use Case	DEBUG-CONTENTS Suitability	Reasoning
Data debugging	Excellent	Essential for detailed data content tracking
Complex data operations	Good	Helps track complex data transformations
Data validation	Good	Provides detailed data validation tracking
Production monitoring	Poor	Performance impact outweighs benefits
Simple programs	Poor	Unnecessary overhead for simple logic

DEBUG-CONTENTS Clause Quick Reference

Usage	Syntax	Example
Basic content tracking	77 debug-contents-item DEBUG-CONTENTS	77 DEBUG-CONTENTS DEBUG-CONTENTS
With data description	77 debug-contents-item DEBUG-CONTENTS PIC...	77 DEBUG-CONTENTS DEBUG-CONTENTS PIC X(100)
Multiple content trackers	Multiple 77 items with DEBUG-CONTENTS	77 DEBUG1 DEBUG-CONTENTS 77 DEBUG2 DEBUG-CONTENTS
Short content tracking	77 debug-contents-item DEBUG-CONTENTS PIC X(50)	77 DEBUG-CONTENTS DEBUG-CONTENTS PIC X(50)
Long content tracking	77 debug-contents-item DEBUG-CONTENTS PIC X(200)	77 DEBUG-CONTENTS DEBUG-CONTENTS PIC X(200)

Test Your Knowledge

1. What is the primary purpose of the DEBUG-CONTENTS clause in COBOL?

To define data types
To track the contents of data items during debugging
To control file operations
To perform calculations

2. At what level is the DEBUG-CONTENTS clause typically used?

01 level only
88 level only
77 level only
Any level except 01

3. What information does DEBUG-CONTENTS provide during debugging?

Only variable names
Only program flow
Actual values and contents of data items
Only error messages

4. When is DEBUG-CONTENTS most useful?

During production runs
During program development and debugging with data analysis
Only during compilation
Only during program termination

5. How does DEBUG-CONTENTS relate to data debugging?

They are completely independent
DEBUG-CONTENTS provides essential content tracking for data debugging
DEBUG-CONTENTS overrides other debugging features
They serve the same purpose

COBOL Tutorial

COBOL DEBUG-CONTENTS Clause - Quick Reference

Overview

Purpose and Usage

Content Tracking Concept

Syntax

Basic Syntax

Data Type Considerations

Debugging Mode Requirements

Common Use Cases

Data Value Tracking

Data Transformation Monitoring

Conditional Content Debugging

Best Practices and Tips

DEBUG-CONTENTS Design Principles

Common Pitfalls to Avoid

Performance Considerations

When to Use DEBUG-CONTENTS

DEBUG-CONTENTS Clause Quick Reference

Test Your Knowledge

Frequently Asked Questions

Related Concepts

DEBUG-ITEM Clause

DEBUG-LINE Clause

DEBUG-NAME Clause

Data Description Entries

Working-Storage Section

Related Pages

COBOL Tutorial

COBOL DEBUG-CONTENTS Clause - Quick Reference

Overview

Purpose and Usage

Content Tracking Concept

Syntax

Basic Syntax

Data Type Considerations

Debugging Mode Requirements

Common Use Cases

Data Value Tracking

Data Transformation Monitoring

Conditional Content Debugging

Best Practices and Tips

DEBUG-CONTENTS Design Principles

Common Pitfalls to Avoid

Performance Considerations

When to Use DEBUG-CONTENTS

DEBUG-CONTENTS Clause Quick Reference

Test Your Knowledge

Frequently Asked Questions

What is the difference between DEBUG-CONTENTS and DEBUG-ITEM?

Can DEBUG-CONTENTS be used in production programs?

What types of data contents can DEBUG-CONTENTS track?

What data type should be used for DEBUG-CONTENTS?

Are there performance implications when using DEBUG-CONTENTS?

Related Concepts

DEBUG-ITEM Clause

DEBUG-LINE Clause

DEBUG-NAME Clause

Data Description Entries

Working-Storage Section

Related Pages