E15 LINKAGE SECTION fields for fixed-length and variable-length records

The fields in the LINKAGE SECTION are used by DFSORT and your routine as stated later in this section. For clarity, the field names from Figure 2 have been used.

To give your COBOL routine the status of the passed records, DFSORT uses the record flags field (RECORD-FLAGS) in the following way:
0 (FIRST-REC)

The new record is the first passed record.

4 (MIDDLE-REC)

The new record is not the first passed record.

8 (END-REC)

All records have been passed to your routine or there were no records to pass.
DFSORT places the next input record in the new record field (NEW-REC). A VLR does not contain an RDW, but DFSORT places the length of this VLR in the new record length field (NEW-REC-LEN). The value in the NEW-REC-LEN field is the length of the record only and does not include the 4 bytes for the RDW.
When your routine places an insertion/replacement record in the return record field (RETURN-REC), the VLR must not contain an RDW; your routine must place the length of this record in the return record length field (RETURN-REC-LEN). The value of the RETURN-REC-LEN field is the length of the record only and must not include the 4 bytes for the RDW.
Each time DFSORT calls your COBOL E15 or COBOL E35 user exit, it passes the user exit a 256-byte user exit area field (EXITAREA). The first time the user exit area field is passed to your COBOL E15 user exit, it contains 256 blanks, and the user exit area length field (EXITAREA-LEN) contains 256.
Any changes you make to the user exit area field or user exit area length fields are passed back both to your COBOL E15 user exit and your COBOL E35 user exit.
Note:
1. Do not set the user exit area length field to more than 256 bytes.
2. If the data used for input was not created by a COBOL run, you need to know the LRECL defined for your data set. For a VLR, the maximum length of the record defined in your COBOL user exit is 4 bytes less than the LRECL value, because COBOL does not include the RDW as part of the record. (Each VLR begins with an RDW field of 4 bytes. The RDW is not included in the record passed to your COBOL user exit.)
3. You need to code only up to the last field that your routine actually uses (for example, up to RETURN-REC if you do not use the user exit area).
4. DFSORT uses the specified or defaulted value for L2 in the RECORD statement to determine the length of the records your E15 user exit passes back to DFSORT. For fixed-length records, be sure that each record your E15 user exit changes or inserts has a length that is equal to the specified or defaulted L2 value. For variable-length records, be sure that each record your E15 user exit changes or inserts has a length that is less than or equal to the specified or defaulted L2 value. Unwanted truncation or abends may occur if DFSORT uses the wrong length for the records passed to it by your E15 user exit.
  For details of the L2 value, see RECORD control statement
  .