15) GEN, CA GEN, CoolGEN batch job related best practice

GEN, CA GEN, CoolGEN batch job related best practice

If a batch step due to its logic doesn’t write even a single record to the output file created in the same step, and a subsequent step has a read from this file. The read fails with an abend.

Best Practice:

The abend occurs because the EOF marker is not set if the file is not opened and closed for output. A dummy step is introduced in between these 2 steps, which will write the EOF marker if the file is empty. This is achieved as follows:

…

//STEP01          PGM=IKJEFT01

//FILE01            DD        DSN=SBBT02.NEW.FILE,DISP=(,CATLG),…

…

//SYSTSIN        DD        *

            EXECDSN progname db2system

/*

//STEP03          PGM=IKJEFT01

//FILE01            DD        DSN=SBBT02.NEW.FILE,DISP=SHR

…

//SYSTSIN        DD        *

            EXECDSN progname db2system

/*

Instead add the following step in between the two steps:

…

//STEP01          PGM=IKJEFT01

//FILE01            DD        DSN=SBBT02.NEW.FILE,DISP=(,CATLG),…

…

//SYSTSIN        DD        *

            EXECDSN progname db2system

/*

//STEP02          PGM=IKJEFT01

//SYSPROC      DD        DSN=SYS2.COOLGEN.CLIST,DISP=SHR

//FILE01           DD        DSN=SBBT02.NEW.FILE,DISP=SHR

//SYSTSIN        DD        *

            EMPTYFLE

/*

//STEP03          PGM=IKJEFT01

//FILE01            DD        DSN=SBBT02.NEW.FILE,DISP=SHR

…

//SYSTSIN        DD        *

            EXECDSN progname db2system

/*

The logic in the REXX program would contain logic like this:

/* Rexx */

“NEWSTACK”

“EXECIO * DISKR FILE01 (FINIS”

Queue “”

“EXECIO * DISKW FILE01 (FINIS”

“DELSTACK”

Exit