MQCXP - Channel exit parameter
The MQCXP structure is passed to each type of exit called by a Message Channel Agent (MCA), client-connection channel, or server-connection channel.
See MQ_CHANNEL_EXIT.
The fields described as "input to the exit" in the descriptions
that follow are ignored by the channel when the exit returns control
to the channel. Any input fields that the exit changes in the channel
exit parameter block will not be preserved for its next invocation.
Changes made to input/output fields (for example, the ExitUserArea field), are preserved for
invocations of that instance of the exit only. Such changes cannot
be used to pass data between different exits defined on the same channel,
or between the same exit defined on different channels.