Rational Developer for System z
Enterprise COBOL for z/OS, Version 4.1, Programming Guide


Deciding which type of pointer to use

Use procedure pointers to call other COBOL programs and to call Language Environment callable services. Use function pointers to communicate with C/C++ programs or with services provided by the Java Native Interface.

Procedure pointers are more efficient than function pointers for COBOL-to-COBOL calls, and are required for calls to Language Environment condition-handling services.

Many callable services written in C return function pointers. You can call such a C function pointer from your COBOL program by using COBOL function pointers as shown below.

 IDENTIFICATION DIVISION.
 PROGRAM-ID. DEMO.
 ENVIRONMENT DIVISION.
 DATA DIVISION.
*
 WORKING-STORAGE SECTION.
 01 FP USAGE FUNCTION-POINTER.
*
 PROCEDURE DIVISION.
     CALL "c-function" RETURNING FP.
     CALL FP.

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