User Exits › COBOL User Exit Facility › Using I/O Requests to Access Information About Data Sets

Using I/O Requests to Access Information About Data Sets

Data set information is maintained by CA JCLCheck in a table ordered alphabetically by data set name (per standard EBCDIC collating sequence).

All I/O requests (such as FIRST, NEXT, LAST) for data set information reference the order of entries in the data set table, not the sequence in which a job stream referenced the various data sets.

If the CA JCLCheck Summary Cross-Reference option (SXREF) is specified, the data set table entries are retained for the entire execution of CA JCLCheck (presumably encompassing multiple job streams). Each job stream is assigned a reference number that is carried as part of the GLOBAL information. This job reference number is also stored with each entry in the data set table. The values of the job reference number in the GLOBAL information and in the DATA SET information are compared as part of user exit processing to ensure that the DATA SET entry retrieved pertains to the current job stream CA JCLCheck is analyzing.

Use the following I/O Request Codes to navigate through the data set table entries:

DATA SET-NAME-FIRST (Request Code 20)

Requests the information associated with the first data set in the current execution of CA JCLCheck (lowest in the EBCDIC collating sequence).

DATA SET-NAME-PREV (Request Code 21)

Requests the data set information for the previous table entry.

DATA SET-NAME-NEXT (Request Code 22)

Requests the data set information for the next table entry.

DATA SET-NAME-LAST (Request Code 23)

Requests the data set information for the last entry in the data set table (highest in the EBCDIC collating sequence).

DATA SET-FOR-THIS-DD (Request Code 24)

Requests the data set information for the data set associated with the DD statement currently defined in the exit program's DD statement information area.

Note: At JCLCHECK-DDEXIT, the DD statement for the current statement is supplied. Also, if the DD statement is defining a data set, the condition name DD-HAS-ASSOCIATED-DATA SET is set, along with supplying the data set information. When DD statement information is obtained by the exit as a result of navigating through the job stream (through I/O Request Codes 4, 5, or 6), the data set information is not automatically provided. You must use Request Code 24 to return the data set information for the DD statement in this case.