You define the ISPF installation-wide exits and installation-written exit routines you want to use by placing entries in the exit definition table, ISPXDT. ISPXDT consists of two sections:

Exit entry definitions

Defines the installation-wide exits and their associated exit routines

Exit data area definitions

Defines the data areas that are used by the exit routines and their size specifications

The ISPMXED, ISPMXLST, ISPMXDEF, ISPMEPT, and ISPMXEND macros define the exit entry definition section of the table, and the ISPMXDD and ISPMDAD macros define the exit data area definitions.

ISPMXED

Defines the start or the end of the exit entry definition section.

>>-ISPMXED--+-START-+------------------------------------------><
            '-END---'   

ISPMXLST

Defines the installation-wide exits where you provide exit routines.

               .-,----------.     
               V            |     
>>-ISPMXLST--(---+--------+-+-)--------------------------------><
                 '-epcode-'       

where:

epcode

The numeric code for a user exit provided by ISPF. The list of codes must be enclosed in parentheses, and must be in ascending order. See Table 1 for a list of the numeric codes.

ISPMXDEF

Begins the definition of exit routines for a particular user exit.

>>-ISPMXDEF--epcode--------------------------------------------><

where:

epcode

The numeric code for an exit point provided by ISPF. You must include this code as an operand for the ISPMXLST macro in order for the user exit to be defined. See Table 1 for a list of the numeric codes.

ISPMEPT

Identifies an exit routine to call at a particular user exit.

>>-ISPMEPT--entryname--+-----------------+---------------------><
                       '-,data-area-name-'   

where:

entryname

Identifies the entry point of the exit routine. This is usually a CSECT name.

data-area-name

Identifies the name of the data area the exit routine uses. The name can be up to 8 characters long. If you list the data area on an ISPMEPT macro, you must define it using the ISPMDAD macro. If you do not specify a data area on the ISPMEPT macro, ISPF does not provide a data area for the exit routine being defined.

Note: Do not use 'NULLAREA' as a data-area-name.

ISPMXEND

Ends the definition of routines for a particular user exit. This macro explicitly ends the ISPMXDEF macro and must be included.

>>-ISPMXEND----------------------------------------------------><

ISPMXDD

Indicates the start or the end of the data-area definition section of ISPXDT. Even if an exit routine does not require a data area, you must code the ISPMXDD START and ISPMXDD END macros.

>>-ISPMXDD--+-START-+------------------------------------------><
            '-END---'   

ISPMDAD

Defines a data area and its size. The data area can be used by one or more exit routines.

>>-ISPMDAD--data-area-name,size--------------------------------><

where:

data-area-name

Identifies the name of the data area an exit routine uses. The name can be up to 8 characters long.

size

Specifies, in bytes, the size of the data area. If the size is not a multiple of eight, ISPF rounds it up to the next multiple of eight.