Compaq COBOL AAQ2G1FTK - Manual (Page 265)

Sharing Files and Locking Records
8.3 Ensuring Successful File Sharing
File Status 91 indicates that a previous access stream has denied access to the
file. That previous access stream opened the file with locking attributes which
conflict with the OPEN statement of the subsequent stream.
You can obtain the values that apply to file-sharing exceptions (or to successful
file-sharing operations), as shown in Example 8–2.
Example 8–2 Program Segment for File Status Values
FILE-CONTROL.
SELECT FILE-NAME ASSIGN TO "fshare.dat"
FILE STATUS IS FILE-STAT.
WORKING-STORAGE SECTION.
01
FILE-STAT PIC XX.
88 FILE-OPENED VALUES "00", "05", "07".
88 FILE-LOCKED VALUE
"91".
01 RETRY-COUNT PIC 9(2).
01 MAX-RETRY PIC 9)2) VALUE 10.
.
.
.
PROCEDURE DIVISION.
DECLARATIVES.
FILE-USE SECTION.
USE AFTER STANDARD EXCEPTION PROCEDURE ON FILE-NAME.
FILE-ERR.
* need declaratives to trap condition, but let main code process it
IF FILE-LOCKED
CONTINUE
ELSE
.
.
.
END-IF.
END DECLARATIVES.
.
.
.
OPEN-FILES.
OPEN I-O FILE-NAME.
IF NOT FILE-OPENED
PERFORM CHECK-OPEN.
.
.
.
CHECK-OPEN.
IF FILE-LOCKED
MOVE 1 to RETRY-COUNT
PERFORM RETRY-OPEN UNTIL FILE-OPENED OR
RETRY-COUNT > MAX-RETRY
IF FILE-LOCKED AND RETRY-COUNT > MAX-RETRY
DISPLAY "File busy...please try again later"
STOP RUN
END-IF
END-IF.
(continued on next page)
Sharing Files and Locking Records 8–13