Using EFS

Like the user exits described in Using your own user exit routines, the DFSORT Extended Function Support (EFS) interface is a means by which you can pass run-time control to an EFS program you write yourself. An EFS program is essential if you want to process double-byte character sets (such as Japanese characters) with DFSORT.

To process Japanese data types with DFSORT, you can use the IBM Double Byte Character Set Ordering Support Program (DBCS Ordering), Licensed Program 5665-360, Release 2.0, or you can use locale processing with the appropriate locale.

Using an EFS program and EFS program exit routines, you can:

Sort or merge user-defined data types (such as double-byte character sets) with user-defined collating sequences
Include or omit records based on the user-defined data types
Provide user-written messages to DFSORT for printing to the message data set
Examine, alter, or ignore control statements or EXEC PARM options prior to processing by DFSORT.

The EFS program can also perform routine tasks, such as opening and initializing data sets, terminating DFSORT, and closing data sets.

You can write your EFS program in any language that uses standard register and linkage conventions, and can:

Pass a parameter list and a record (if you provide the EFS01 and EFS02 exit routines in the EFS program) in register 1
Pass a return code in general register 15.

Note:

DFSORT does not support EFS programs for Conventional merge or tape work data set sort applications.
VLSHRT is not allowed if EFS processing is in effect and an EFS01 or EFS02 exit routine is provided by the EFS program.
If you use locale processing for SORT, MERGE, INCLUDE, or OMIT fields, you must not use an EFS program. DFSORT's locale processing may eliminate the need for an EFS program. See OPTION control statement for information related to locale processing.
If you use symbol processing, you must not use an EFS program.

The DFSORT target library, SICEUSER, contains a mapping macro called ICEDEFS, which provides a separate Assembler DSECT for the EFS parameter list.