The message notify user routine might receive control at the completion of a message-out request. The information available to the user routine through the message notification parameter list (MNPL) includes the user data provided on the IXCMSGOX request that sent the original message, information about the send to each potential target member, and, if relevant, information about the responses to the message. Note that it is possible for the message notify user routine to receive control before the IXCMSGOX service that processed the request returns control to the caller.

If a response is neither received nor saved, the system discards the response when the message notify user routine gives up control.