User Exits › Changing Routing Data Through Exit Routines

Changing Routing Data Through Exit Routines

You can change some of the routing data associated with a message through the GCMSRCXT routine. To do this, use the message selection table that is passed to these routines in the parameter list at Register 1.

Make note of the following information if you use this table:

• Messages in a z/VM system do not have MCS flags, descriptor codes, or routing codes associated with them. However, you can use exit routines to assign these to a message. This will affect the way the message is routed or displayed when it is sent to an external z/OS system.
• Improper modification of the MCS flags or console ID fields can cause the message to be rejected.
• Some of the routing data associated with a message (for example, the message ID) may be duplicated in the message text. If you want this information to be consistent, change both the routing data and the message text.
• Do not modify the sequence number in the message selection table.
• See the GCMWTOXP mapping macro for a complete mapping of this table.

USERID     DS      XL8      Issuing user ID
MESSNAME   DS      XL12     Message ID
MCSFLAGS   DS      XL2      Standard MCS flags
DESCODES   DS      XL2      Descriptor codes
ROUTCODE   DS      XL16     Routing codes
           DS      XL2      Reserved
EXITFLAG   DS      X        Flag byte for exit PLIST
MVSSYS     EQU     X80      Message from MVS system
VMSYS      EQU     X40      Message from VM system
           DS      XL5      Reserved
SEQNUM     DS      XL4      Unique sequence number assigned to message