IBM TSO/E REXX User Manual

TSO/E BACKGROUND (IKJEFT01) MVS BATCH (IRXJCL)
Messages are displayed in the output file. Messages may appear in two places; the JCL output
listing and in the output file. To suppress messages in the
output file, use the TRACE OFF instruction.
REQUIREMENTS
TSO/E BACKGROUND (IKJEFT01) MVS BATCH (IRXJCL)
The default DDs are SYSTSPRT and SYSTSIN. The default DDs are SYSTSPRT and SYSTSIN.
Initiated by executing program IKJEFT01. Initiated by executing program IRXJCL.
JCL should be written in a fixed block, 80-byte record
data set.
JCL should be written in a fixed block, 80-byte record
data set.
Exec that is invoked can be either a member of a PDS or
a sequential data set.
Exec that is invoked must be a member of a PDS.
Data set may be allocated to either SYSEXEC or
SYSPROC.
Data set must be allocated to the SYSEXEC DD.
Defining Language Processor Environments
Before an exec can be processed, a language processor environment must exist. A
language processor environment defines the way a REXX exec is processed and
how it accesses system services. Because MVS contains different types of address
spaces and each one accesses services a different way, REXX in TSO/E provides
three default parameters modules that define language processor environments.
They are:
v IRXTSPRM - for TSO/E
v IRXPARMS - for non-TSO/E
v IRXISPRM - for ISPF
The defaults are set by TSO/E but they can be modified by a system programmer.
What is a Language Processor Environment?
A language processor environment defines characteristics, such as:
v The search order used to locate commands and external routines
v The ddnames for reading and writing data and from which execs are loaded
v The valid host command environments and the routines that process commands
in each host command environment
v The function packages (user, local, and system) that are available in the
environment and the entries in each package
v Whether execs running in the environment can use the data stack
v The names of routines that handle system services, such as I/O operations,
loading of an exec, obtaining and freeing storage, and data stack requests
Note: A language processor environment is different from a host command
environment. The language processor environment is the environment in
which a REXX exec runs. The host command environment is the
environment to which the language processor passes commands for
execution. The valid host command environments are defined by the
language processor environment.
Summary of TSO/E Background and MVS Batch
Chapter 13. Using REXX in TSO/E and Other MVS Address Spaces 181

IBM TSO/E REXX Specifications

General

Brand	IBM
Model	TSO/E REXX
Category	Computer Hardware
Language	English

Summary

Part 1. Learning the REXX Language

Chapter 1. Introduction

Explains the REXX programming language, its features, and suitability for various users.

Chapter 2. Writing and Running a REXX Exec

Details the process of writing, running, and understanding REXX execs, including syntax rules and common issues.

Chapter 3. Using Variables and Expressions

Covers REXX variables, expressions, operators, and tracing techniques for data manipulation and calculations.

Chapter 4. Controlling the Flow Within an Exec

Explains how to alter REXX exec execution using conditional, looping, and interrupt instructions.

Chapter 5. Using Functions

Describes REXX functions, including built-in, user-written, and packages, and how to use them.

Chapter 6. Writing Subroutines and Functions

Guides on writing, calling, and passing information to REXX subroutines and functions.

Chapter 7. Manipulating Data

Covers REXX data manipulation using compound variables, stems, and various parsing techniques.

Part 2. Using REXX

Chapter 8. Entering Commands from an Exec

Explains how REXX execs can interact with the operating system by issuing TSO/E and host commands.

Chapter 9. Diagnosing Problems Within an Exec

Details techniques for diagnosing and debugging REXX execs using tracing and special variables.

Chapter 10. Using TSO/E External Functions

Describes TSO/E external functions available for interacting with the system and performing specific tasks.

Chapter 11. Storing Information in the Data Stack

Explains how to use the REXX data stack for temporary storage, passing information, and managing buffers.

Chapter 12. Processing Data and Input/Output Processing

Covers dynamic REXX expression modification and processing data to/from data sets using EXECIO.

Chapter 13. Using REXX in TSO/E and Other MVS Address Spaces

Explains how to run REXX execs in TSO/E and non-TSO/E MVS address spaces and available services.

Part 3. Appendixes

Appendix A. Allocating Data Sets

Guides on creating and allocating data sets, including checklists for ISPF/PDF and ALLOCATE commands.

Appendix B. Specifying Alternate Libraries with the ALTLIB Command

Details using the ALTLIB command to specify and manage alternative libraries for implicit execution.

Appendix C. Comparisons Between CLIST and REXX

Compares REXX and CLIST languages, highlighting similarities and differences in features and capabilities.

Appendix D. Notices

Provides legal notices, warranty disclaimers, copyright, and trademark information.

Bibliography

TSO/E Publications

Lists IBM publications related to TSO/E, including administration, CLISTs, and general information.

Related Publications

Lists IBM publications related to z/OS MVS and ISPF, covering system programming and administration.

Index