ATTPRN

The CICS® transaction specifies the primary resource name field (ATTPRN) in the RESOURCE field of the BUILD ATTACH command.

This field, when sent by CICS to IMS, names an IMS LTERM or transaction code that is the message destination. When this parameter is omitted, IMS uses the first eight characters of the data stream to identify the message destination.

Recommendation: To maintain consistency between IMS and CICS, use this field to name an LTERM for IMS message switches and place transaction codes in the first eight characters of the data stream.

When received by CICS in a reply from IMS, this field contains the value that CICS sent to IMS as the return primary resource name (ATTRPRN) on the outbound message. CICS ignores the ATTPRN if it is received in a reply returned from IMS.

Exceptions:

After session restart, ATTPRN is used to determine the identity of the terminal that originated this transaction and must be acquired during the restart.
When the reply is to a nonresponse or nonconversational transaction issued by CICS with SEND LAST, ATTPRN is used.

If the reply is to be returned on the same session as that of the incoming message, IMS automatically wraps the value received on the incoming RPRN field into the PRN field. MFS can be used to set or override this value on IMS output.