Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

 ◄Key► ◄Summary►                             ◄Up► ◄Contents► ◄Index► ◄Back►
────────────────────────────────────────────────────────────────────────────
 
     This directive has no effect if the LIST directive is not specified.
     Specifying XREF sets RESEQ.
 
     To produce the cross-reference listing the compiler needs extra
     work space on the disk. The space needed depends on the number of
     data items and procedure names and the number of times they are
     referenced.
 
     When the XREF directive is specified, extra information is added to
     the end of the .LST file produced:
 
       the name of the data item
       the type of the data item
       the line number where the data item was defined, shown as n#
       the line numbers where the data item was updated, shown as n*
       the line numbers where the data item was tested, shown as n?
       the number of times the data item appeared in the cross-reference
           listing, shown as (X   n)
       procedure name
       type of procedure
 
     The following is an extract from a .LST file for a simple program:
 
          1 WORKING-STORAGE SECTION.
          2 01 A  PIC 9(2).
          3
          4 PROCEDURE DIVISION.
          5 main section.
          6     MOVE 1 TO A
          7     IF A = 1 DISPLAY "HELLO" END-IF
          8     stop run.
     ...
     * A                              Numeric DISPLAY
     *          2#      6*      7?                                  (X    3)
     *
     *               1 data-names
     *
     * MAIN                           Section
     *          5#                                                  (X    1)
     *
     *
     *               1 procedure-names
     * End of cross reference listing
 
     The cross-referencing information shows that there is one data item,
     A, of type numeric display, which is defined on line 2, updated on
     line 6, and tested on line 7. The (X    3) at the end of the line
     refers to the number of times the data item appears in the
     cross-reference listing. The procedure name Main also appears in the
     listing, as a Section which is referenced only once.
 
     See also ◄RESEQ►
                                    -♦-