Using REXX in different address spaces

TSO/E provides support for the REXX programming language in any MVS™ address space. You can run REXX execs in the TSO/E address space and in any non-TSO/E address space, such as CICS® TS or IMS™.

The REXX language consists of keyword instructions and built-in functions that you use in a REXX exec. The keyword instructions and built-in functions are described in Keyword instructions and Functions, respectively.

TSO/E also provides TSO/E external functions and REXX commands you can use in a REXX exec. The functions are described in TSO/E external functions. The TSO/E REXX commands provide additional services that let you:

Control I/O processing to and from data sets
Perform data stack requests
Change characteristics that control how a REXX exec runs
Check for the existence of a specific host command environment.

TSO/E REXX commands describes the commands.

In an exec, you can use any of the keyword instructions and built-in functions regardless of whether the exec runs in a TSO/E or non-TSO/E address space. There are, however, differences in the TSO/E external functions, commands, and programming services you can use in an exec depending on whether the exec will run in a TSO/E address space or in a non-TSO/E address space. For example, you can use the TSO/E external function SETLANG in an exec that runs in any MVS address space. However, you can use the LISTDSI external function only in execs that run in a TSO/E address space. The following topics describe the services you can use in execs that run in TSO/E and non-TSO/E address spaces:

TSO/E provides the TSO/E environment service, IKJTSOEV, that lets you create a TSO/E environment in a non-TSO/E address space. If you use IKJTSOEV and then run a REXX exec in the TSO/E environment that is created, the exec can contain TSO/E external functions, commands, and services that an exec running in a TSO/E address space can use. That is, the TSO host command environment (ADDRESS TSO) is available to the exec. z/OS TSO/E Programming Services describes the TSO/E environment service and the different considerations for running REXX execs within the environment.

TSO/E REXX is the implementation of the SAA Procedures Language on the MVS system. By using the keyword instructions and functions that are defined for the SAA Procedures Language, you can write REXX programs that can run in any of the supported SAA environments. See SAA Common Programming Interface REXX Level 2 Reference for more information.