To have your function routine receive control for SSI function code 9, you must use the IEAVG700 interface. You only need to issue IEAVG700 once for each IPL. Use the following coding fragment to call module IEAVG700:

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*     Register declarations
R1       EQU  1                  Declaration for register 1
R13      EQU  13                 Declaration for register 13
R15      EQU  15                 Declaration for register 15

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DOBRDCST EQU  *                  Request broadcast of WTO/WTORs
         LA   R1,SCSRPLST        Get addressability to SCSR
         ST   R1,SCSRPTR         Save pointer for standard linkage
         XC   SCSRPLST(SCSPLEN),SCSRPLST  Zero out parameter list
         MVC  SCSACRO,SCSRACRN   Set acronym value
         MVI  SCSVER,SCSVERSN    Set version level
         OI   SCSFUNC1,SCSBRDON  Indicate to broadcast WTO/WTORs
         LA   R1,SCSRPTR         Set up standard entry linkage
         LA   R13,SAVEAREA       Set up standard save area
         LINK EP=IEAVG700        Call subsystem console routine
         LTR  R15,R15            See if request was successful
         BNZ  BRDFAIL            Branch to process unsuccessful call
* Processing continues here for successful call
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*        Module static storage area
SCSRACRN DC   CL4'SCSR'

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*        Module dynamic storage area
SCSRPTR  DS   A                   Pointer to SCSR
SAVEAREA DS   18F                 Standard save area

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*        Include mapping for Subsystem Console Service Routine
         IEZVG100                 Include SCSR mapping macro
 

Your installation might also use the WTO/WTOR call (SSI function code 9) to take any of the following actions against a message:

• Alteration — including text and routing information
• Deletion
• Generation of a reply (in the case of WTOR)
• Suppression.

Your installation can use the following methods to affect WTO/WTOR message processing:

• Message processing facility (MPF) — see z/OS MVS Planning: Operations.
• Installation-written exit routines — see z/OS MVS Installation Exits.
• Automation — see z/OS MVS Planning: Operations.

In choosing which method to use to affect WTO/WTOR message processing, take the following into consideration:

• The WTO general exit (IEAVMXIT) or message processing facility (MPF) exits are the recommended ways to take actions against MVS™ messages prior to their distribution to consoles and the system log, because they get control before the SSI gets control, and they can be changed easily through the SYS1.PARMLIB member. See z/OS MVS Installation Exits for information about IEAVMXIT and MPF exits.
• The primary subsystem (JES) is usually the first subsystem to get control from the SSI.
• Automation subsystems (such as NetView®) are common users of SSI function code 9. Automation subsystems also get control from the SSI so that, depending on what you want your program to do, placing your subsystem before or after an automation product may be of concern. For example, subsystems may alter messages. If you are using an automation product that gets its messages from the SSI, it may not receive the final version of a message if there are other subsystems that subsequently change the message. If so, make sure you code the subsystems in SYS1.PARMLIB member IEFSSNxx in the order in which you want the subsystems to get control.