Identify the message to be delivered with the TOKEN parameter of IXCMSGIX. The value of TOKEN is passed in the MEPL or MNPL parameter list — MEPLMSGITOKEN, the token for a message presented to a message user routine or MNPLTRMSGITOKEN, the token for a response message presented to a message notify user routine. Note that this message token is valid as input to IXCMSGIX while the user routine is in control, as long as the message has not been saved or discarded using the IXCMSGC service. When the user routine gives up control, or saves or discards the message using the IXCMSGC service, XCF invalidates the message token.

If the message is to be delivered on a system running a release prior to OS/390® Release 3, you can use the MSGTOKEN parameter to identify the message. The value of MSGTOKEN is passed in the MEPL parameter list — MEPLMTOK, the 32-bit token for a message presented to a message user routine. Use the TOKEN parameter instead of the MSGTOKEN parameter on systems running OS/390 Release 3. The TOKEN parameter is required when IXCMSGIX is issued within a user routine that gained control through the IXCMSGC Call Exit service or within a message notify user routine.