Conditional compilation directives in Cobol

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About this task

COBOL compilation directives are special instructions evaluated by the compiler during compilation (not at runtime). They control the compilation process by specifying how the source code is handled and by determining which sections of code are included in or excluded from the final program.

Characteristics

Syntax: Begin with >> (double angle bracket)

Processing: Evaluated during compilation, before running the program

Scope: Affect compiler behavior, not runtime behavior

Supported directives

Following compiler conditional directives that are supported:
  • >>DEFINE - Defines compilation variables
  • >>EVALUATE - Multi-way conditional compilation
  • >>IF - Conditional compilation with branching
Not supported cases
  • Successive WHEN conditions enabling the same text
  • Non-integer numerical values for compiler variables

Defining Variables

Internal Definition (in source code)

>>DEFINE PLAYERCOUNT AS 5

This defines a compilation variable named PLAYERCOUNT with value 5.

External Definition (outside source files)

If compilation variables are not defined in the source code, they can be specified externally in the .dat file within the [PREPROCESSOR_DEFINITIONS] section using the COBOL_DEFINES key.

Example: 
[PREPROCESSOR_DEFINITIONS]
COBOL_DEFINES=PLAYERCOUNT="5";PARADEF=1;PLAYERCOUNT=3;ORD2=2;DEFI=4;WORD2=2;