Information DFSORT passes to your routine at E35 user exit

Your E35 user exit routine is entered each time DFSORT prepares to place a record (including the first record) in the output area. DFSORT passes three fields to your routine:

The address of the record leaving DFSORT, which usually follows the record in the output area. End of input is reached when there are no more records to pass to your E35 user exit; DFSORT indicates end of input by setting this address to zero before entering your E35 user exit.
After end of input is reached, DFSORT continues to enter your user exit routine until a return code of 8 is passed back.

Your E35 user exit must not change the address of the record leaving DFSORT.
The address of a record in the output area is zero the first time your routine is entered because there is no record in the output area at that time. It remains zero provided you pass a return code of 4 (delete record) to DFSORT.
Note: If the record pointed to is variable-length, it has an RDW at this point even if output is to a VSAM data set.
The user exit address constant is passed to your user exit exactly as it was set by your E15 or E32 user exit or invoking program's parameter list.

Note: The user exit address constant must not be used for a Conventional merge or tape work data set sort application.