Calling PL/I subroutines from a COBOL Application

Notes:

The information in this topic is specific to programs executing under Enterprise Server, but also applicable to standalone applications running outside of Enterprise Server as well.
When a PL/I program interacts with COBOL programs using the same data, the COBOL programs must be compiled with -sign "IBM".

Note:

To use PL/I subroutines executing under the control of a COBOL Application you need to initialize the PL/I run-time system prior to invoking the PL/I program and shut it down before termination. The initialization call (__lpi_init()) can be made within a COBOL "initcall" program, but the de-initialization call (__lpi_fini_and_return() ) must not be made from a COBOL EXIT Proc as the processing happens after the File Handler has closed all open files at step termination and will result in any buffered stream output being lost.

A very simple example COBOL program which initializes the PL/I run-time system, calls a PL/I subroutine and then terminates the PL/I run-time system is shown below.

      $SET CASE
       identification division.
       program-id. FETCHER.

       environment division.
       configuration section.
       special-names.
          call-convention 8 is litlink.

       data division.
       working-storage section.
       01 pli-lang                     pic x(02) comp-5 value 0.
       01 pli-retcode                  pic x(04) comp-5.
       01 argv                         pointer value null.  

       procedure division.
       
           *> Initialize PL/I RTS
           call litlink '__lpi_init' using by value 0 size 4
                                             by reference argv
                                             by reference argv 
                                             by value pli-lang
       
           *> Call the PL/I subroutine
           call 'PLISUB'
           
           *> Shutdown the PL/I RTS
           call litlink '__lpi_fini_and_return' using 
                                            by value pli-lang
                                            by reference pli-retcode
           
           move 0 to return-code           
           goback.
          
       end program FETCHER.