Exit protocol

The scrambling exit is called during a copy operation with an input and output template, and where the output field has been defined with Scramble Type 4 ("Exit") and mapped to an input field. The exit is called in these situations:
The first call to the exit for each field is an initialization call that causes the exit to perform set-up procedures. A 1024-byte user area is provided, in addition to the user constant for the exit to use.
This call is repeated for each instance of the field being copied. On this call, the exit is expected to provide Z Data Tools with the scrambled output value for the field, or a directive for Z Data Tools to scramble the field.
The last call for each field is a termination call that causes the exit to perform clean-up procedures.