Resource attribute update user exit programs can allow the associated API command by setting return code 0, and disallow the API command by setting return code 8. Resource attribute update user exit programs for the following API commands can also allow the command while adjusting resource attributes by setting return code 4: Alter, Copy, Create, Migrate, Rename, and Update. (User exits programs for Delete and Rename cannot adjust resource attributes.)
Similarly, change package pre-processing user exit programs can allow or disallow the API command, and modify parameters to affect the API command. Return codes set by change package post-processing user exit programs have no effect on the associated API command, because these programs are invoked only after the API command has successfully completed.
Operations qualification user exit programs can either
allow or disallow the associated API command (Install, Discard, or
Newcopy).
or