Language Environment provides a set of IBM-supplied default runtime options that control certain aspects of program processing. A system programmer can modify the IBM-supplied defaults on a system-level or region-level basis to suit the application programmers' need at their site. An application programmer can further refine these options based on individual program needs. When an application runs, runtime options are merged in a specific order of precedence to determine the actual values in effect. For more information, see Order of precedence.

For syntax and detailed information about individual runtime options, including how Language Environment runtime options map to specific HLL options, see z/OS Language Environment Programming Reference.