As described in the previous topic (Changing the default values for initializing an environment), you can change the default parameter values IRXINIT uses to initialize a language processor environment by providing your own parameters modules. You can also call the initialization routine, IRXINIT, to initialize a new environment. When you call IRXINIT, you can pass parameter values on the call. Initialization and termination routines describes IRXINIT and its parameters and return codes.

Whether you provide your own load modules or invoke IRXINIT directly, you cannot change some parameters. You can use other parameters only in language processor environments that are not integrated into TSO/E or in environments that are integrated into TSO/E. In addition, there are some restrictions on parameter values depending on the values of other parameters in the same environment and on parameter values that are defined for the previous environment. This topic describes the parameters you can and cannot use in the two types of language processor environments. The topic also describes different considerations for using the parameters. For more information about the parameters and their descriptions, see Characteristics of a Language Processor Environment.