COBOL Tutorial

COBOL LC_MESSAGES Environment Variable - Quick Reference

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Overview

The LC_MESSAGES environment variable controls message formatting and localization in COBOL applications. This is essential for internationalized applications that need to display system messages, error messages, and user interface text in the appropriate language and cultural format.

Purpose and Usage

Message localization - Displays messages in appropriate language
Error message formatting - Controls error message display
System message language - Determines system message language
User interface text - Affects UI text formatting
Cultural conventions - Handles locale-specific message formats

Message Localization Concept

English (en_US): "File not found"

German (de_DE): "Datei nicht gefunden"

French (fr_FR): "Fichier introuvable"

Spanish (es_ES): "Archivo no encontrado"

Japanese (ja_JP): "ファイルが見つかりません"

Different locales display the same system messages in different languages.

Syntax and Usage

LC_MESSAGES is set as an environment variable and affects all message formatting and display operations in the COBOL program.

Environment Variable Syntax

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* Setting LC_MESSAGES environment variable
* Unix/Linux shell
export LC_MESSAGES=en_US.UTF-8
 
* Windows Command Prompt
set LC_MESSAGES=en_US.UTF-8
 
* JCL for mainframe
//SETUP    EXEC PGM=IEFBR14
//SYSPRINT DD SYSOUT=*
//SYSIN    DD *
SET LC_MESSAGES=en_US.UTF-8
/*
 
* Common locale values
LC_MESSAGES=C              * Standard English messages
LC_MESSAGES=POSIX          * POSIX standard messages
LC_MESSAGES=en_US.UTF-8    * US English with UTF-8
LC_MESSAGES=de_DE.UTF-8    * German with UTF-8
LC_MESSAGES=fr_FR.UTF-8    * French with UTF-8
LC_MESSAGES=es_ES.UTF-8    * Spanish with UTF-8
LC_MESSAGES=ja_JP.UTF-8    * Japanese with UTF-8

LC_MESSAGES is set as an environment variable before running the COBOL program.

COBOL Program Example

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* COBOL program demonstrating LC_MESSAGES effects
       IDENTIFICATION DIVISION.
       PROGRAM-ID. MESSAGES-DEMO.
       
       ENVIRONMENT DIVISION.
       CONFIGURATION SECTION.
       
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  ERROR-CODE      PIC 9(4).
       01  USER-MESSAGE    PIC X(100).
       01  SYSTEM-MESSAGE  PIC X(200).
       
       PROCEDURE DIVISION.
       MAIN-LOGIC.
           * Set error code
           MOVE 1001 TO ERROR-CODE
           
           * Generate user message (this will be affected by LC_MESSAGES)
           PERFORM GENERATE-USER-MESSAGE
           
           * Display message using current LC_MESSAGES setting
           DISPLAY USER-MESSAGE
           
           * System error messages will also use LC_MESSAGES
           PERFORM TEST-FILE-OPERATION
           
           STOP RUN.
       
       GENERATE-USER-MESSAGE.
           * Create localized user message
           EVALUATE ERROR-CODE
               WHEN 1001
                   MOVE "Processing completed successfully" TO USER-MESSAGE
               WHEN 1002
                   MOVE "Invalid input data detected" TO USER-MESSAGE
               WHEN 1003
                   MOVE "System error occurred" TO USER-MESSAGE
               WHEN OTHER
                   MOVE "Unknown error code" TO USER-MESSAGE
           END-EVALUATE.
       
       TEST-FILE-OPERATION.
           * This will generate system messages based on LC_MESSAGES
           OPEN INPUT NONEXISTENT-FILE
           * System error message will be in the language specified by LC_MESSAGES

The message display operations will use the LC_MESSAGES setting.

Error Handling Example

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* Error handling with LC_MESSAGES
       IDENTIFICATION DIVISION.
       PROGRAM-ID. ERROR-HANDLING.
       
       ENVIRONMENT DIVISION.
       INPUT-OUTPUT SECTION.
       FILE-CONTROL.
           SELECT INPUT-FILE ASSIGN TO "INPUT.DAT"
                  ORGANIZATION IS LINE SEQUENTIAL
                  FILE STATUS IS FILE-STATUS.
       
       DATA DIVISION.
       FILE SECTION.
       FD  INPUT-FILE.
       01  INPUT-RECORD     PIC X(80).
       
       WORKING-STORAGE SECTION.
       01  FILE-STATUS      PIC XX.
       01  ERROR-MESSAGE    PIC X(100).
       
       PROCEDURE DIVISION.
       MAIN-LOGIC.
           * Open file - system messages will use LC_MESSAGES
           OPEN INPUT INPUT-FILE
           
           IF FILE-STATUS NOT = "00"
               * Generate localized error message
               PERFORM HANDLE-FILE-ERROR
           END-IF
           
           * Continue processing
           PERFORM PROCESS-FILE
           
           CLOSE INPUT-FILE
           STOP RUN.
       
       HANDLE-FILE-ERROR.
           * Create localized error message based on file status
           EVALUATE FILE-STATUS
               WHEN "35"
                   MOVE "File not found or access denied" TO ERROR-MESSAGE
               WHEN "37"
                   MOVE "File permission denied" TO ERROR-MESSAGE
               WHEN "39"
                   MOVE "File already exists" TO ERROR-MESSAGE
               WHEN OTHER
                   MOVE "Unknown file error occurred" TO ERROR-MESSAGE
           END-EVALUATE
           
           DISPLAY "Error: " ERROR-MESSAGE.

Error handling uses LC_MESSAGES for localized error messages.

Common Use Cases

LC_MESSAGES is essential in various scenarios where proper message localization is critical for user experience and application functionality.

International Applications

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* Multi-language application with LC_MESSAGES
       IDENTIFICATION DIVISION.
       PROGRAM-ID. INT-MESSAGES.
       
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  USER-LANGUAGE   PIC X(10).
       01  SELECTED-LOCALE  PIC X(20).
       01  WELCOME-MESSAGE  PIC X(100).
       01  HELP-MESSAGE     PIC X(200).
       
       PROCEDURE DIVISION.
       MAIN-LOGIC.
           * Set locale based on user preference
           PERFORM SET-USER-LOCALE
           
           * Display localized messages
           PERFORM DISPLAY-WELCOME
           PERFORM DISPLAY-HELP
           
           STOP RUN.
       
       SET-USER-LOCALE.
           * This would typically read user preference
           ACCEPT USER-LANGUAGE
           
           EVALUATE USER-LANGUAGE
               WHEN "ENGLISH"
                   MOVE "en_US.UTF-8" TO SELECTED-LOCALE
               WHEN "GERMAN"
                   MOVE "de_DE.UTF-8" TO SELECTED-LOCALE
               WHEN "FRENCH"
                   MOVE "fr_FR.UTF-8" TO SELECTED-LOCALE
               WHEN "SPANISH"
                   MOVE "es_ES.UTF-8" TO SELECTED-LOCALE
               WHEN OTHER
                   MOVE "en_US.UTF-8" TO SELECTED-LOCALE
           END-EVALUATE.
       
       DISPLAY-WELCOME.
           * Display welcome message in appropriate language
           EVALUATE SELECTED-LOCALE
               WHEN "en_US.UTF-8"
                   MOVE "Welcome to the application!" TO WELCOME-MESSAGE
               WHEN "de_DE.UTF-8"
                   MOVE "Willkommen in der Anwendung!" TO WELCOME-MESSAGE
               WHEN "fr_FR.UTF-8"
                   MOVE "Bienvenue dans l'application!" TO WELCOME-MESSAGE
               WHEN "es_ES.UTF-8"
                   MOVE "¡Bienvenido a la aplicación!" TO WELCOME-MESSAGE
           END-EVALUATE
           
           DISPLAY WELCOME-MESSAGE.

Multi-language applications use LC_MESSAGES for localized user interface.

System Integration

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* System integration with localized messages
       IDENTIFICATION DIVISION.
       PROGRAM-ID. SYSTEM-INTEGRATION.
       
       ENVIRONMENT DIVISION.
       CONFIGURATION SECTION.
       
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  SYSTEM-COMMAND  PIC X(100).
       01  COMMAND-RESULT  PIC X(200).
       01  STATUS-MESSAGE  PIC X(100).
       
       PROCEDURE DIVISION.
       MAIN-LOGIC.
           * Execute system command
           MOVE "ls -la" TO SYSTEM-COMMAND
           CALL "SYSTEM" USING SYSTEM-COMMAND
           
           * System messages will be in LC_MESSAGES language
           * For example, error messages like:
           * English: "Permission denied"
           * German: "Zugriff verweigert"
           * French: "Accès refusé"
           
           * Process command result
           PERFORM PROCESS-RESULT
           
           STOP RUN.
       
       PROCESS-RESULT.
           * Handle system command results
           * System error messages will use LC_MESSAGES locale
           IF COMMAND-RESULT CONTAINS "error"
               DISPLAY "System error occurred"
               * The actual error message will be in LC_MESSAGES language
           ELSE
               DISPLAY "Command executed successfully"
           END-IF.

System integration uses LC_MESSAGES for localized system messages.

User Interface

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* User interface with localized messages
       IDENTIFICATION DIVISION.
       PROGRAM-ID. UI-MESSAGES.
       
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  MENU-OPTIONS.
           05  OPTION-1     PIC X(30).
           05  OPTION-2     PIC X(30).
           05  OPTION-3     PIC X(30).
       01  USER-CHOICE      PIC X(1).
       01  CONFIRM-MESSAGE  PIC X(50).
       
       PROCEDURE DIVISION.
       MAIN-LOGIC.
           * Display localized menu
           PERFORM DISPLAY-MENU
           
           * Get user input
           ACCEPT USER-CHOICE
           
           * Display confirmation in appropriate language
           PERFORM DISPLAY-CONFIRMATION
           
           STOP RUN.
       
       DISPLAY-MENU.
           * Set menu options based on LC_MESSAGES locale
           EVALUATE TRUE
               WHEN LC_MESSAGES = "en_US.UTF-8"
                   MOVE "1. Process Data" TO OPTION-1
                   MOVE "2. Generate Report" TO OPTION-2
                   MOVE "3. Exit" TO OPTION-3
               WHEN LC_MESSAGES = "de_DE.UTF-8"
                   MOVE "1. Daten verarbeiten" TO OPTION-1
                   MOVE "2. Bericht erstellen" TO OPTION-2
                   MOVE "3. Beenden" TO OPTION-3
               WHEN LC_MESSAGES = "fr_FR.UTF-8"
                   MOVE "1. Traiter les données" TO OPTION-1
                   MOVE "2. Générer rapport" TO OPTION-2
                   MOVE "3. Quitter" TO OPTION-3
           END-EVALUATE
           
           DISPLAY "Menu Options:"
           DISPLAY OPTION-1
           DISPLAY OPTION-2
           DISPLAY OPTION-3.
       
       DISPLAY-CONFIRMATION.
           * Display confirmation message
           EVALUATE USER-CHOICE
               WHEN "1"
                   MOVE "Processing data..." TO CONFIRM-MESSAGE
               WHEN "2"
                   MOVE "Generating report..." TO CONFIRM-MESSAGE
               WHEN "3"
                   MOVE "Exiting application..." TO CONFIRM-MESSAGE
               WHEN OTHER
                   MOVE "Invalid selection" TO CONFIRM-MESSAGE
           END-EVALUATE
           
           DISPLAY CONFIRM-MESSAGE.

User interface uses LC_MESSAGES for localized menu and confirmation messages.

Best Practices and Tips

Following these best practices ensures effective use of LC_MESSAGES in COBOL applications.

LC_MESSAGES Best Practices

Set appropriate locale - Choose locale that matches your users
Use UTF-8 encoding - Ensure proper character set support
Test with real users - Verify message clarity in target language
Document locale requirements - Specify required LC_MESSAGES settings
Consider cultural differences - Be aware of locale-specific message formats
Handle missing translations - Plan for fallback message handling

Common Locale Settings

Locale	Description	Use Case
C	Standard English messages	Simple English applications
en_US.UTF-8	US English with UTF-8	US-based applications
de_DE.UTF-8	German with UTF-8	German applications
fr_FR.UTF-8	French with UTF-8	French applications
es_ES.UTF-8	Spanish with UTF-8	Spanish applications
ja_JP.UTF-8	Japanese with UTF-8	Japanese applications

Performance Considerations

Message catalog loading - Locale-specific message catalogs need to be loaded
Memory usage - Message tables require additional memory
Translation lookup - Message translation may add minimal overhead
Character encoding - UTF-8 encoding may impact display performance
Caching - Some systems cache message catalogs for performance
Testing - Always test message display with actual locale settings

When to Use Different LC_MESSAGES Settings

Use Case	Recommended Setting	Reasoning
Simple English applications	C or en_US.UTF-8	Standard English messages
International applications	Appropriate locale	Localized user experience
Multi-language support	User preference	Best user experience
System integration	System locale	Consistent system messages
Legacy systems	C	Compatibility with existing messages

LC_MESSAGES Quick Reference

Operation	Effect	Example
System messages	Uses locale message language	File error messages
Error messages	Localized error display	Runtime error messages
User interface	Localized UI text	Menu options, prompts
Status messages	Localized status display	Processing status
Help text	Localized help content	User assistance messages

Test Your Knowledge

1. What is the primary purpose of the LC_MESSAGES environment variable in COBOL?

To control file I/O operations
To define message formatting and localization rules
To set numeric formatting rules
To control date and time formatting

2. Which of the following operations is most affected by LC_MESSAGES?

Arithmetic operations
System message formatting and display
File operations
Date calculations

3. What happens if LC_MESSAGES is not set in a COBOL program?

The program will terminate with an error
The system will use the default message formatting rules
All message operations will fail
The program will use English messages only

4. Which locale setting would be appropriate for French message display?

LC_MESSAGES=C
LC_MESSAGES=fr_FR.UTF-8
LC_MESSAGES=en_US
LC_MESSAGES=POSIX

5. How does LC_MESSAGES affect error handling in COBOL?

It has no effect on error handling
It determines the language and format of error messages
It only affects error handling on numeric fields
It controls the error handling algorithm used

COBOL Tutorial

COBOL LC_MESSAGES Environment Variable - Quick Reference

Overview

Purpose and Usage

Message Localization Concept

Syntax and Usage

Environment Variable Syntax

COBOL Program Example

Error Handling Example

Common Use Cases

International Applications

System Integration

User Interface

Best Practices and Tips

LC_MESSAGES Best Practices

Common Locale Settings

Performance Considerations

When to Use Different LC_MESSAGES Settings

LC_MESSAGES Quick Reference

Test Your Knowledge

Frequently Asked Questions

Related Concepts

LC_COLLATE Environment Variable

LC_CTYPE Environment Variable

Error Handling

User Interface Design

Internationalization

Related Pages

COBOL Tutorial

COBOL LC_MESSAGES Environment Variable - Quick Reference

Overview

Purpose and Usage

Message Localization Concept

Syntax and Usage

Environment Variable Syntax

COBOL Program Example

Error Handling Example

Common Use Cases

International Applications

System Integration

User Interface

Best Practices and Tips

LC_MESSAGES Best Practices

Common Locale Settings

Performance Considerations

When to Use Different LC_MESSAGES Settings

LC_MESSAGES Quick Reference

Test Your Knowledge

Frequently Asked Questions

What is the difference between LC_MESSAGES and other LC_* environment variables?

How do you set LC_MESSAGES in a COBOL program?

What are the common LC_MESSAGES values and their meanings?

How does LC_MESSAGES affect performance in COBOL applications?

What should you consider when choosing an LC_MESSAGES setting for a COBOL application?

Related Concepts

LC_COLLATE Environment Variable

LC_CTYPE Environment Variable

Error Handling

User Interface Design

Internationalization

Related Pages