CONFIGURATION SECTION

CONFIGURATION SECTION provides the computer environment information in which the program is compiled and executed. It is an optional section in the COBOL program.

Syntax -

[CONFIGURATION SECTION.
[SOURCE-COMPUTER. computer-name]
[OBJECT-COMPUTER. computer-name]
[SPECIAL-NAMES.   names-entry]]

Note! All statements coded in [ ] are optional.

SOURCE-COMPUTER. {source-computer-entry} -

SOURCE-COMPUTER provides the computer name on which the source program is compiled.

computer-name - Source computer name where the program is coded.
WITH DEBUGGING MODE - Activates a compile-time debugging switch for debugging lines coded in the program.

Debugging Lines -

A debugging line is a code with a "D" in column 7.
Debugging lines are allowed to code in the ENVIRONMENT DIVISION, DATA DIVISION, and PROCEDURE DIVISION.
If the DEBUGGING MODE is coded, the code with "D" in the 7th column is considered as code.
If the DEBUGGING MODE is not coded, the code with "D" in the 7th column is treated as comments.

Practical Example -

Scenario1 - Example to describe how the DEBUGGING MODE is enabled in COBOL programming.

Code -

Full Example

----+----1----+----2----+----3----+----4----+----5----+
       ...
       ENVIRONMENT DIVISION.
       CONFIGURATION SECTION. 
       SOURCE-COMPUTER. IBM3278 WITH DEBUGGING MODE.
       OBJECT-COMPUTER. IBM3278.
 
       PROCEDURE DIVISION.

      D    DISPLAY "DISPLAYING DEBUGGING LINE".
           DISPLAY "DISPLAYING NORMAL LINE".
		   ...

Output -

DISPLAYING DEBUGGING LINE
DISPLAYING NORMAL LINE

Explaining Example -

DEBUGGING MODE is coded on SOURCE-COMPUTER. Thus, all the debugging lines in the program are considered as code during the compilation and executed when we ran the program.

Scenario2 - Example to describe how the DEBUGGING MODE is disabled in COBOL programming.

Code -

Full Example

----+----1----+----2----+----3----+----4----+----5----+
       ...
       ENVIRONMENT DIVISION.
       CONFIGURATION SECTION.
       SOURCE-COMPUTER. IBM3278.
       OBJECT-COMPUTER. IBM3278.

       PROCEDURE DIVISION.

      D    DISPLAY "DISPLAYING DEBUGGING LINE". 
           DISPLAY "DISPLAYING NORMAL LINE". 
		   ...

Output -

DISPLAYING NORMAL LINE

Explaining Example -

DEBUGGING MODE not coded with SOURCE-COMPUTER. i.e., DEBUGGING MODE disabled. All the debugging lines are considered comments during the compilation and not executed when we ran the program.

OBJECT-COMPUTER. {object-computer-entry} -

OBJECT-COMPUTER paragraph specifies the system name where the object code will be executed.

Computer-name - Specifies where the program is executed. If it is coded, the program runs only on specified machine and doesn't run on the current machine.
PROGRAM COLLATING SEQUENCE IS alphabet-name - A collating sequence is used to overwrite the system collating sequence. The alphabet-name should be defined in the SPECIAL-NAMES paragraph to specify the collating sequence.

Note! If this clause is not coded, the system's default collating sequence is in effect.

SPECIAL-NAMES. {special-names-entry} -

SPECIAL-NAMES paragraph overrides system-defined objects like environment names, user-defined mnemonic names, collating sequences, class names, currency strings, commas, and decimal points.

environment-name-1 - specifies the system name where the compiler took the actions.
mnemonic-name-1 - user-defined name.
ALPHABET clause - Declares a name with a character code or collating sequence. For example -
```
SPECIAL-NAMES. ALPHABET ALPHA-NAME IS EBCDIC.
```
SYMBOLIC CHARACTERS clause - Applies a variable to single-byte character sets. Each character represented is an alphanumeric character. For example -
```
SPECIAL-NAMES. SYMBOLIC CHARACTERS SC-A IS 97.
```
CURRENCY SIGN clause - sets the currency symbol in a PICTURE clause. For example -
```
SPECIAL-NAMES. CURRENCY SIGN IS "$".
```
DECIMAL-POINT IS COMMA clause - swaps the functions of the period. Also, change the comma in PICTURE character-strings and numeric literals. For example -
```
SPECIAL-NAMES. DECIMAL-POINT IS COMMA.
```

Practical Example -

Scenario - Example to describe how the PROGRAM COLLATING SEQUENCE is used in COBOL programming.

Code -

Full Example

----+----1----+----2----+----3----+----4----+----5----+
       ...
       ENVIRONMENT DIVISION. 
       CONFIGURATION SECTION.
       SOURCE-COMPUTER. IBM3278.
       OBJECT-COMPUTER. IBM3278
                PROGRAM COLLATING SEQUENCE IS TEST-COLLATE.
       SPECIAL-NAMES. ALPHABET TEST-COLLATE IS 'STUVWXY'. 
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 WS-VAR        PIC X(01).

       PROCEDURE DIVISION. 

           MOVE LOW-VALUE     TO  WS-VAR.
           DISPLAY "LOWEST VALUE IS:  " WS-VAR.
		   ...

Output -

LOWEST VALUE IS:  S

Explaining Example -

TEST COLLATE is the PROGRAM COLLATING SEQUENCE that overrides the ALPHABET system collating sequence. i.e., the EBCDIC character sequence has been overridden by the 'STUVWXY'. Therefore, the LOW-VALUE is 'S,' and the same is displayed in the output.