The LC_CTYPE environment variable controls character classification and case conversion operations in COBOL applications. This is essential for internationalized applications that need to handle different languages, character sets, and cultural conventions for character behavior.
Different locales have different rules for what constitutes letters, digits, and other character types.
LC_CTYPE is set as an environment variable and affects all character classification and case conversion operations in the COBOL program.
12345678910111213141516171819202122* Setting LC_CTYPE environment variable * Unix/Linux shell export LC_CTYPE=en_US.UTF-8 * Windows Command Prompt set LC_CTYPE=en_US.UTF-8 * JCL for mainframe //SETUP EXEC PGM=IEFBR14 //SYSPRINT DD SYSOUT=* //SYSIN DD * SET LC_CTYPE=en_US.UTF-8 /* * Common locale values LC_CTYPE=C * Standard ASCII character classification LC_CTYPE=POSIX * POSIX standard character classification LC_CTYPE=en_US.UTF-8 * US English with UTF-8 LC_CTYPE=de_DE.UTF-8 * German with UTF-8 LC_CTYPE=tr_TR.UTF-8 * Turkish with UTF-8 LC_CTYPE=fr_FR.UTF-8 * French with UTF-8 LC_CTYPE=ja_JP.UTF-8 * Japanese with UTF-8
LC_CTYPE is set as an environment variable before running the COBOL program.
12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849* COBOL program demonstrating LC_CTYPE effects IDENTIFICATION DIVISION. PROGRAM-ID. CTYPE-DEMO. ENVIRONMENT DIVISION. CONFIGURATION SECTION. DATA DIVISION. WORKING-STORAGE SECTION. 01 TEST-STRING PIC X(50). 01 LETTER-COUNT PIC 9(3) VALUE ZERO. 01 DIGIT-COUNT PIC 9(3) VALUE ZERO. 01 UPPER-STRING PIC X(50). 01 LOWER-STRING PIC X(50). PROCEDURE DIVISION. MAIN-LOGIC. * Initialize test string with mixed characters MOVE "Hello World 123! Äöüß ÇçĞğ" TO TEST-STRING * Count letters and digits using current LC_CTYPE PERFORM COUNT-CHARACTERS * Perform case conversion using current LC_CTYPE PERFORM CASE-CONVERSION * Display results DISPLAY "Original: " TEST-STRING DISPLAY "Letters: " LETTER-COUNT DISPLAY "Digits: " DIGIT-COUNT DISPLAY "Upper: " UPPER-STRING DISPLAY "Lower: " LOWER-STRING STOP RUN. COUNT-CHARACTERS. * Count letters and digits using INSPECT INSPECT TEST-STRING TALLYING LETTER-COUNT FOR ALL CHARACTERS BEFORE INITIAL SPACE WHEN CHARACTERS ARE ALPHABETIC INSPECT TEST-STRING TALLYING DIGIT-COUNT FOR ALL CHARACTERS BEFORE INITIAL SPACE WHEN CHARACTERS ARE NUMERIC. CASE-CONVERSION. * Convert to upper and lower case MOVE FUNCTION UPPER-CASE(TEST-STRING) TO UPPER-STRING MOVE FUNCTION LOWER-CASE(TEST-STRING) TO LOWER-STRING.
The character classification and case conversion operations will use the LC_CTYPE setting.
123456789101112131415161718192021222324252627282930313233343536373839404142* Using INSPECT with LC_CTYPE IDENTIFICATION DIVISION. PROGRAM-ID. INSPECT-CTYPE. DATA DIVISION. WORKING-STORAGE SECTION. 01 INPUT-STRING PIC X(100). 01 ALPHA-COUNT PIC 9(3) VALUE ZERO. 01 NUMERIC-COUNT PIC 9(3) VALUE ZERO. 01 PUNCT-COUNT PIC 9(3) VALUE ZERO. 01 SPACE-COUNT PIC 9(3) VALUE ZERO. PROCEDURE DIVISION. MAIN-LOGIC. * Get input string ACCEPT INPUT-STRING * Analyze string using current LC_CTYPE rules PERFORM ANALYZE-STRING * Display analysis results DISPLAY "Analysis Results:" DISPLAY "Alphabetic: " ALPHA-COUNT DISPLAY "Numeric: " NUMERIC-COUNT DISPLAY "Punctuation: " PUNCT-COUNT DISPLAY "Spaces: " SPACE-COUNT STOP RUN. ANALYZE-STRING. * Count different character types INSPECT INPUT-STRING TALLYING ALPHA-COUNT FOR ALL CHARACTERS WHEN CHARACTERS ARE ALPHABETIC INSPECT INPUT-STRING TALLYING NUMERIC-COUNT FOR ALL CHARACTERS WHEN CHARACTERS ARE NUMERIC INSPECT INPUT-STRING TALLYING PUNCT-COUNT FOR ALL CHARACTERS WHEN CHARACTERS ARE SPECIAL-NAMES INSPECT INPUT-STRING TALLYING SPACE-COUNT FOR ALL SPACES.
The INSPECT verb will use LC_CTYPE rules for character classification.
LC_CTYPE is essential in various scenarios where proper character classification and case conversion are critical for application functionality.
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051* Validating data using LC_CTYPE character classification IDENTIFICATION DIVISION. PROGRAM-ID. CTYPE-VALIDATION. DATA DIVISION. WORKING-STORAGE SECTION. 01 VALIDATION-RECORD. 05 FIELD-NAME PIC X(30). 05 FIELD-VALUE PIC X(50). 01 VALIDATION-RESULT PIC X(20). PROCEDURE DIVISION. MAIN-LOGIC. * Validate different field types using current LC_CTYPE PERFORM VALIDATE-ALPHA-FIELD PERFORM VALIDATE-NUMERIC-FIELD PERFORM VALIDATE-ALPHANUMERIC-FIELD STOP RUN. VALIDATE-ALPHA-FIELD. MOVE "Customer Name" TO FIELD-NAME MOVE "Müller" TO FIELD-VALUE * Check if field contains only alphabetic characters INSPECT FIELD-VALUE TALLYING ALPHA-COUNT FOR ALL CHARACTERS WHEN CHARACTERS ARE ALPHABETIC IF ALPHA-COUNT = LENGTH OF FIELD-VALUE MOVE "VALID" TO VALIDATION-RESULT ELSE MOVE "INVALID - Non-alphabetic" TO VALIDATION-RESULT END-IF DISPLAY FIELD-NAME ": " VALIDATION-RESULT. VALIDATE-NUMERIC-FIELD. MOVE "Account Number" TO FIELD-NAME MOVE "12345" TO FIELD-VALUE * Check if field contains only numeric characters INSPECT FIELD-VALUE TALLYING NUMERIC-COUNT FOR ALL CHARACTERS WHEN CHARACTERS ARE NUMERIC IF NUMERIC-COUNT = LENGTH OF FIELD-VALUE MOVE "VALID" TO VALIDATION-RESULT ELSE MOVE "INVALID - Non-numeric" TO VALIDATION-RESULT END-IF DISPLAY FIELD-NAME ": " VALIDATION-RESULT.
Data validation uses LC_CTYPE rules for character classification.
1234567891011121314151617181920212223242526272829303132* Case conversion using LC_CTYPE rules IDENTIFICATION DIVISION. PROGRAM-ID. CASE-CONVERSION-DEMO. DATA DIVISION. WORKING-STORAGE SECTION. 01 ORIGINAL-STRING PIC X(50). 01 UPPER-STRING PIC X(50). 01 LOWER-STRING PIC X(50). 01 TITLE-STRING PIC X(50). PROCEDURE DIVISION. MAIN-LOGIC. * Test case conversion with different locales MOVE "Hello World! Äöüß ÇçĞğ" TO ORIGINAL-STRING * Convert to upper case using current LC_CTYPE MOVE FUNCTION UPPER-CASE(ORIGINAL-STRING) TO UPPER-STRING * Convert to lower case using current LC_CTYPE MOVE FUNCTION LOWER-CASE(ORIGINAL-STRING) TO LOWER-STRING * Display results DISPLAY "Original: " ORIGINAL-STRING DISPLAY "Upper: " UPPER-STRING DISPLAY "Lower: " LOWER-STRING * Note: Results depend on LC_CTYPE setting * German: Äöüß becomes ÄÖÜß * Turkish: Iı becomes II, İi becomes İİ STOP RUN.
Case conversion follows locale-specific rules defined by LC_CTYPE.
1234567891011121314151617181920212223242526272829303132333435363738394041* Text processing using LC_CTYPE character classification IDENTIFICATION DIVISION. PROGRAM-ID. TEXT-PROCESSING. DATA DIVISION. WORKING-STORAGE SECTION. 01 INPUT-TEXT PIC X(200). 01 PROCESSED-TEXT PIC X(200). 01 WORD-COUNT PIC 9(3) VALUE ZERO. 01 CHAR-COUNT PIC 9(3) VALUE ZERO. PROCEDURE DIVISION. MAIN-LOGIC. * Get input text ACCEPT INPUT-TEXT * Process text using current LC_CTYPE rules PERFORM PROCESS-TEXT * Display processing results DISPLAY "Processed: " PROCESSED-TEXT DISPLAY "Words: " WORD-COUNT DISPLAY "Characters: " CHAR-COUNT STOP RUN. PROCESS-TEXT. * Count words (sequences of alphabetic characters) * This depends on LC_CTYPE definition of alphabetic PERFORM VARYING I FROM 1 BY 1 UNTIL I > LENGTH OF INPUT-TEXT IF INPUT-TEXT(I:1) IS ALPHABETIC ADD 1 TO CHAR-COUNT * Check if this starts a new word IF I = 1 OR INPUT-TEXT(I-1:1) IS NOT ALPHABETIC ADD 1 TO WORD-COUNT END-IF END-IF END-PERFORM * Convert to title case (first letter of each word uppercase) MOVE FUNCTION UPPER-CASE(INPUT-TEXT) TO PROCESSED-TEXT.
Text processing uses LC_CTYPE rules for character classification.
Following these best practices ensures effective use of LC_CTYPE in COBOL applications.
| Locale | Description | Use Case |
|---|---|---|
| C | Standard ASCII character classification | 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 |
| tr_TR.UTF-8 | Turkish with UTF-8 | Turkish applications |
| fr_FR.UTF-8 | French with UTF-8 | French applications |
| ja_JP.UTF-8 | Japanese with UTF-8 | Japanese applications |
| Use Case | Recommended Setting | Reasoning |
|---|---|---|
| Simple English data | C or en_US.UTF-8 | Fast, standard classification |
| International data | Appropriate locale | Proper character classification |
| Turkish applications | tr_TR.UTF-8 | Correct case conversion (I/ı, İ/i) |
| Multi-language apps | Primary language locale | Best character behavior |
| Performance critical | C | Fastest classification |
| Operation | Effect | Example |
|---|---|---|
| Character classification | Uses locale character rules | INSPECT FOR ALPHABETIC |
| Case conversion | Uses locale case rules | FUNCTION UPPER-CASE |
| INSPECT verb | Character type detection | INSPECT TALLYING |
| Data validation | Character validation | IF FIELD IS ALPHABETIC |
| Text processing | Character analysis | Word counting, parsing |
1. What is the primary purpose of the LC_CTYPE environment variable in COBOL?
2. Which of the following operations is most affected by LC_CTYPE?
3. What happens if LC_CTYPE is not set in a COBOL program?
4. Which locale setting would be appropriate for Turkish text processing?
5. How does LC_CTYPE affect the INSPECT verb in COBOL?
Understanding string comparison and sorting behavior.
Controlling message formatting and localization.
Working with strings in COBOL applications.
Using the INSPECT verb with character classification.
Validating data using proper character classification.