CBL_OPEN_FILE Organization parameter for reading binary files

Hi,

Your AI’s syntax is completely wrong. You should reference the documentation instead.
Here is an example that will open and read the contents of a binary file such as a .jpg file.

 

      *----------------------------------------------------------------*
      *                    Read Byte Stream File                       *
      *                                                                *
      *  This program demonstrates how to use the Visual COBOL callable*
      *  library routines to open and read a file as a simple byte     *
      *  stream. This program uses a data buffer size of 1000 and reads*
      *  the entire file in a single read so it assumes that the file  *
      *  is not greater that 1000 bytes in size. The data buffer size  *
      *  can be adjusted for larger files or the file could be read in *
      *  chunks using the file-offset parameter.                       *
      *                                                                *
      *  The first call to CBL_READ_FILE with flags set to 128 will    *
      *  return the file size into the file-offset parameter so we know*
      *  how many bytes to read.                                       *
      *                                                                *
      *  The data-buffer read will be moved to a dynamic length data   *
      *  item using the file-size as the length so that trailing spaces*
      *  in the buffer will be discarded.                              *
      *----------------------------------------------------------------*
       identification division.
       program-id. readbytestream.

       environment division.
       configuration section.

       data division.
       working-storage section.
       78 BUFFER-SIZE    value 1000.
       01 file-content   pic x dynamic.
       01 data-buffer    pic x(BUFFER-SIZE) value spaces.
       01 filename       pic x(256) value spaces.

       01 access-mode    pic x comp-x value 0.
       78 access-read-only value 1.
       78 access-write-only value 2.
       78 access-read-write value 3.
       78 access-greater-4GB value 64.

       01 deny-mode          pic x comp-x value 3.
       78 deny-read-write    value 0.
       78 deny-write         value 1.
       78 deny-read          value 2.
       78 deny-none          value 3.

       01 device             pic x comp-x value zeroes. *> always 0
       01 file-handle        pic x(4) comp-5 value zeroes.
       01 file-offset        pic x(8) comp-x value zeroes.
       01 byte-count         pic x(4) comp-x value zeroes.

       01 flags              pic x comp-x value zeroes.
       78 read-filesize-only value 128.
       78 read-data          value 0.
       procedure division.

           move "myfile.jpg" to filename
           compute access-mode = access-read-only + access-greater-4GB
           move deny-write to deny-mode

           call "CBL_OPEN_FILE" using filename
                                      access-mode
                                      deny-mode
                                      device
                                      file-handle
           end-call
           if return-code not = 0
               display "error on open = " return-code
               stop run
           end-if

           move read-filesize-only to flags
           *> File-offset will contain the filesize
           call "CBL_READ_FILE" using file-handle
                                      file-offset
                                      byte-count
                                      flags
                                      data-buffer
           end-call
           if return-code not = 0
               display "error on get filesize = " return-code
               stop run
           end-if

           move read-data to flags
           move file-offset to byte-count *> read the entire file
           *> buffer must be large enough
           *> set the length of the dynamic length data-item that will
           *> receive the contents of the file.
           set length of file-content to byte-count
           *> First byte in the file is at offset 0
           move 0 to file-offset
           call "CBL_READ_FILE" using file-handle
                                      file-offset
                                      byte-count
                                      flags
                                      data-buffer
           end-call
           if return-code not = 0
               display "error on read file = " return-code
               stop run
           end-if

           *> file-content will contain only the data read - extra bytes
           *> in data-buffer
           move data-buffer(1:byte-count) to file-content

           call "CBL_CLOSE_FILE" using file-handle

           goback.