Coding the checkpoint ARB
The application program and
AR/CTL
use the ARB to exchange information such as call functions and results. Code the ARB in the working storage area of the application program. The program can use a single ARB for all calls, or it can use a separate ARB for checkpoint support and for each sequential file that uses ASAM support. If the program uses a single ARB for multiple call types, it must reinitialize the ARB for each call.
The following example shows the ARB in COBOL:
...
DATA DIVISION.
WORKING-STORAGE SECTION.
01 ARCARB.
02 ARCARB-TYPE PIC X(8) VALUE '$ARCARB '.
02 FUNC-CODE PIC X(8) VALUE ' '.
02 FILLER PIC X(8) VALUE SPACES.
02 STATUS-CODE PIC X(2) VALUE SPACES.
02 FILLER PIC X(2) VALUE SPACES.
02 FILLER PIC X(4) VALUE SPACES.
ARB Type | This field serves to identify the ARB. |
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Function Code | This field (at offset 8 from the beginning byte 0) indicates the type of access you want for the next call. If the call is a checkpoint call, you can leave the function code field blank or set it to FORCE. A function code of FORCE overrides the checkpoint pacing decision and forces checkpoint processing to occur for the checkpoint identified in the call. You can use the FORCE function to ensure that a restart point is established after a long-running procedure such as a sort. |
Status Code | This field contains the status code that the application program can check to determine the results of a call to AR/CTL. The status codes that AR/CTL can return are recorded with the calls. |
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