The following rules apply to the interaction of threads with run units:
- The CHAIN and CALL PROGRAM statements normally act as if the program does a STOP RUN followed by the beginning of a new run
unit. The implied STOP RUN destroys all threads other than the one executing the CHAIN or CALL PROGRAM statement.
- If you have more than one thread running, you may not start a nested run unit (accomplished with the CALL RUN statement).