Listen (-LSN)

Use the Listen adapter command (-LSN) for data sources to dictate the length of time (in seconds) that the IBM® MQ queue manager allows the adapter to wait for a message to be received. Map execution is suspended until the message is received or until the specified time lapses.

-LSN {0|S|wait_time_in_sec}
Do not wait at all. If there is no input available, the adapter does not wait for more messages.
This is an infinite wait time.
This is the number of seconds that the adapter waits (in seconds) for a message.

If the Listen adapter command (-LSN) is not issued and the message is not available for the adapter to retrieve immediately, the map completes, but returns the following warning in the audit log:

(2033) MQSeries Warning: No message available.