Restrictions in a multiprocess, multiuser environment

Programs that change the security environment cannot run in a multiprocess, multiuser environment. A multiprocess, multiuser environment is an environment in which there are multiple z/OS UNIX processes in an address space (enabled by the environment variable _BPX_SHAREAS=YES.) Each process has a different MVS™ identity; that is, it has its own process-level ACEE anchored at the TCB (TCBSenv) level. To prevent a user running under one MVS identity from affecting all the other processes in the address space, or creating a new process with an identity other than the one the user is running under, certain callable services are restricted.

See the descriptions of these callable services for further information about the restrictions.