cobol OPEN statement OPEN sample, with LINAGE mini report


Example

COBOL *****************************************************************
      * Example of LINAGE File Descriptor
      * Tectonics: $ cocb -x linage.cob
      *            $ ./linage <filename ["linage.cob"]>
      *            $ cat -n mini-report
      *****************************************************************
       IDENTIFICATION DIVISION.
       PROGRAM-ID. linage-demo.

       ENVIRONMENT DIVISION.
       INPUT-OUTPUT SECTION.
       FILE-CONTROL.
           select optional data-file assign to file-name
               organization is line sequential
               file status is data-file-status.
           select mini-report assign to "mini-report".

       DATA DIVISION.
       FILE SECTION.
       FD  data-file.
       01  data-record.
           88 endofdata        value high-values.
           02 data-line        pic x(80).
       FD  mini-report
           linage is 16 lines
               with footing at 15
               lines at top 2
               lines at bottom 2.
       01  report-line         pic x(80).

       WORKING-STORAGE SECTION.
       01  command-arguments   pic x(1024).
       01  file-name           pic x(160).
       01  data-file-status    pic 99.
       01  lc                  pic 99.
       01  report-line-blank.
           02 filler           pic x(18) value all "*".
           02 filler           pic x(05) value spaces.
           02 filler           pic x(34)
               VALUE "THIS PAGE INTENTIONALLY LEFT BLANK".
           02 filler           pic x(05) value spaces.
           02 filler           pic x(18) value all "*".
       01  report-line-data.
           02 body-tag         pic 9(6).
           02 line-3           pic x(74).
       01  report-line-header.
           02 filler           pic x(6) VALUE "PAGE: ".
           02 page-no          pic 9999.
           02 filler           pic x(24).
           02 filler           pic x(5) VALUE " LC: ".
           02 header-tag       pic 9(6).
           02 filler           pic x(23).
           02 filler           pic x(6) VALUE "DATE: ".
           02 page-date        pic x(6).

       01  page-count          pic 9999.

       PROCEDURE DIVISION.

       accept command-arguments from command-line end-accept.
       string
           command-arguments delimited by space
           into file-name
       end-string.
       if file-name equal spaces
           move "linage.cob" to file-name
       end-if.

       open input data-file.
       read data-file
           at end
               display "File: " function trim(file-name) " open error"
               go to early-exit
       end-read.

       open output mini-report.

       write report-line
           from report-line-blank
       end-write.

       move 1 to page-count.
       accept page-date from date end-accept.
       move page-count to page-no.
       write report-line
           from report-line-header
           after advancing page
       end-write.

       perform readwrite-loop until endofdata.

       display
           "Normal termination, file name: "
           function trim(file-name)
           " ending status: "
           data-file-status
       close mini-report.

      * Goto considered harmful?  Bah!  :)
       early-exit.
       close data-file.
       exit program.
       stop run.

      ****************************************************************
       readwrite-loop.
       move data-record to report-line-data
       move linage-counter to body-tag
       write report-line from report-line-data
           end-of-page
               add 1 to page-count end-add
               move page-count to page-no
               move linage-counter to header-tag
               write report-line from report-line-header
                   after advancing page
               end-write
       end-write
       read data-file
           at end set endofdata to true
       end-read
       .

      *****************************************************************
      * Commentary
      * LINAGE is set at a 20 line logical page
      *  16 body lines
      *   2 top lines
      *   A footer line at 15 (inside the body count)
      *   2 bottom lines
      * Build with:
      * $ cobc -x -Wall -Wtruncate linage.cob
      * Evaluate with:
      * $ ./linage
      * This will read in linage.cob and produce a useless mini-report
      * $ cat -n mini-report
      *****************************************************************
       END PROGRAM linage-demo.