* ==== TYPE: ADV-MATCH-PARAM-CALL ====
      * FEATURE: Matching + subprogram call (CALL + LINKAGE)
      * STATEMENT: CALL / IF
      * BRANCHES: 2, DECISIONS: 1
      * ADVERSARIAL: Combined matching and subprogram structure
       IDENTIFICATION DIVISION.
       PROGRAM-ID. CALLMT.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 WS-MAST-KEY PIC X(10).
       01 WS-TRAN-KEY PIC X(10).
       01 WS-RESULT   PIC X(10).
       LINKAGE SECTION.
       01 LS-PARAM    PIC X(10).
       PROCEDURE DIVISION.
       MAIN.
           CALL 'SUBPGM' USING WS-RESULT.
           IF WS-MAST-KEY = WS-TRAN-KEY
               MOVE WS-MAST-KEY TO WS-RESULT
           ELSE
               MOVE SPACES TO WS-RESULT.
           STOP RUN.