TSO/E provides load modules, exits, and replaceable routines that
you can use to customize REXX processing.
For REXX,
TSO/E provides three default parameters modules that are load modules
containing the default values for initializing
language processor environments. A
language processor environment is the
environment in which a REXX exec
executes. The parameter modules are:
- IRXTSPRM for TSO/E
- IRXISPRM for ISPF
- IRXPARMS for MVS™.
You can change the default values used to initialize a language processor environment by providing
your own parameters module. For more information, see Characteristics for a language processor environment.
The following describes the REXX exits:
- Pre-environment initialization exit (IRXINITX)
IRXINITX performs
processing before a new language processor environment is initialized.
Use it to prevent the initialization of a language processor environment, change
parameters used for initializing a language processor environment, or perform
special pre-environment initialization processing.
- Post-environment initialization exit (IRXITTS or IRXITMV)
IRXITTS
performs processing after the new language processor environment is initialized
for an environment integrated with TSO/E. Use it to perform special
processing for a language processor environment initialized
with the parameters of the IRXINITX exit.
IRXITMV performs processing
after a new language processor environment is
initialized for an environment not integrated with TSO/E. Use it
to perform special processing for a language processor environment initialized
with the parameters of the IRXINITX exit.
- Environment termination exit (IRXTERMX)
IRXTERMX performs processing
before a language processor environment is
terminated. Use IRXTERMX to prevent the termination of a language processor environment or perform
special processing with the parameters of the IRXINITX exit.
- Exec processing exit
Use the exec processing exit to prevent
the execution of a REXX exec
or perform special processing before a REXX exec is executed.
- Exec initialization exit
Use this exit to access and update REXX variables
before the first clause in the exec is processed.
- Exec termination exit
Use this exit to access and update REXX variables
before the REXX variable
pool is terminated.
- Attention handling exit
Use the attention handling exit to
perform special attention processing. This exit can only be used
for an environment integrated with TSO/E.
For information about the REXX exits, see Customizing CLIST and REXX processing.
In addition to the REXX exits,
TSO/E supplies replaceable routines you can use to customize REXX processing.
TSO/E provides the following routines that handle different types
of system services, which you can replace:
- Loading and freeing execs
- Reading and writing output
- Handling data stack services
- Obtaining and freeing storage
- Obtaining the user or terminal ID
- Determining whether the message ID is displayed with a REXX error message
- Handling host commands for a specific language processor environment
For information about the replaceable routines, see Replaceable routines.