COBOL Manual for TNS and TNS/R Programs

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1331

Tape Input and Output

HP COBOL Manual for TNS and TNS/R Programs—522555-006

27-11

Labeled Tape Files

The system label-processing software checks that the DEFINE attributes are

consistent with the tape label specifications; if they are not, the operating environment

issues an open error.

If the tape label and the data on the tape are inconsistent (for example, if the tape label

specifies fixed-length records but the tape contains variable-length records), results are

unpredictable.

Converting HP COBOL Programs to Use Labeled Tape Files

To convert an HP COBOL program to use a labeled tape file, set up an OBEY

command file that:

1. Assigns the file-name in the file description entry to a DEFINE name

2. Enables the creation of DEFINEs

3. Deletes any existing DEFINE that has the name selected in Step 1

4. Creates the DEFINE

5. Runs the program

6. Clears the assignment (from Step 1) and the DEFINE (from Step 4) to prevent their

affecting other processes created by the same TACL process

In Example 27-5, the commands in the OBEY command file commands convert the

HP COBOL program to use a labeled tape file. The file-name in the file description

entry is MONTHLY-SALES, the DEFINE name is =SALES^JAN86, and the program

name is QUOTAS.

The DEFINE in Example 27-5 is for a tape file with ANSI standard labels and fixed-

length records 80 characters long. Because the file description entry contains the

clause LABEL RECORDS ARE OMITTED, the HP COBOL run-time library sets the file

status code, STATUS-KEY, to “97.” If the program does not contain code that takes

specific action when STATUS-KEY is “97.” the program can use a labeled tape file

without changes to the source code or recompilation.

Example 27-5. Converting a COBOL95 Program to Use Labeled Tape

Files (page 1 of 2)

HP COBOL file-control entry:

SELECT MONTHLY-SALES ASSIGN TO $TAPE2

ORGANIZATION SEQUENTIAL

ACCESS MODE SEQUENTIAL

FILE STATUS IS STATUS-KEY.

...

HP COBOL file description entry for a tape file:

FD MONTHLY-SALES

RECORD CONTAINS 80 CHARACTERS

LABEL RECORDS ARE OMITTED.