Your E32 user exit routine is entered each time the merge program requires a new input record. DFSORT passes three fields to your routine:

• The increment of the next file to be used for input. The file increment is 0,4,8,...,N–4, where N is four times the number of input files. Thus, the increment 0 (zero) represents the first input file, 4 the second file, 8 the third, and so on.
• The address of the next input record. Your routine must provide a separate input buffer for each input file used. An input buffer containing the first record for a file must not be altered until you have passed the first record from each file to DFSORT.
• The user exit address constant. If you invoked DFSORT with a user exit address constant in the parameter list, the address constant is passed to your E32 user exit the first time it is entered. This address constant can be changed by your E32 user exit any time it is entered; the address constant is passed along on subsequent entries to your E32 user exit and E35 user exit. For example, you can obtain a dynamic storage area, use it in your E32 user exit, and pass its address to your E35 user exit.