UseDLQ (MQLONG)

This field specifies whether the dead-letter queue (or undelivered message queue) is used when messages cannot be delivered by channels.

It can contain one of the following values:

MQUSEDLQ_NO: Messages that cannot be delivered by a channel are treated as a failure. The channel either discards the message, or the channel ends, in accordance with the NPMSPEED setting.
MQUSEDLQ_YES: When the DEADQ queue manager attribute provides the name of a dead-letter queue, then it is used, else the behavior is as for NO. YES is the default value.