This option specifies the operating system and hardware platform under which the PL/I program will run. It also enforces the parameters that can be received by a MAIN procedure.
In addition, a suboption allows you to exploit the hardware platform on which the object code will run.
.-WINDOWS-. >>-SYSTEM--(--+---------+--)----------------------------------->< +-CICS----+ '-IMS-----'
For MAIN procedures compiled with SYSTEM(CICS), OPTIONS (BYVALUE) is assumed and PROCEDURE OPTIONS(BYADDR), if specified, is diagnosed.