ATTPRN

This parameter is sent on a return reply from a remotely executed message that results from the returning reply message of the ATTACH ATTRPRN parameter that was sent on a message request. However, in situations where the message request contains no input ATTRPRN, the output ATTPRN parameter can be created using MFS, based on user-defined information.

IMS does not permit specification of IMS command verbs as PRNs.

This destination normally represents a terminal (an LTERM), rather than an application program. If the request ATTRPRN/reply ATTPRN represents an application program, consider the synchronous versus asynchronous relationship between the source application program and the remote transaction executions.

Further, you should consider input transaction security requirements for processing and routing the reply. If supplied on input to IMS, the ATTPRN is used as an IMS transaction code or as the LTERM name for a message switch. The data stream is not edited for destination and security information. If the ATTPRN represents a transaction, and if password security (which applies to statically defined terminals only) was defined for the node, an input security error results, because no available source exists for the input password.

Related reading: For more information on password security, see IMS Version 15.5 System Administration.

The ATTPRN is rejected during IMS conversation mode when an application has previously inserted the transaction code into the SPA. The ATTPRN only applies to a single message instance and overrides, but does not destroy, any preset destination established using an IMS /SET command. Subsequent messages with no ATTACH FM header or with an ATTACH FM header where the ATTPRN parameter is not supplied, can use any preset destination previously established by the IMS /SET command or by an IMS transaction code, LTERM name, or command verb supplied in the data or through MFS formatting.

IMS sets the output ATTPRN on a return reply to the value contained in the ATTRPRN parameter optionally provided within the ATTACH of the previous input request.

MFS DPM provides a means to optionally specify, override, or delete the output ATTPRN using an output message format descriptor. When this parameter is not present, a 1-byte field containing X'00' is sent with the output ATTACH FM header.

The ATTPRN is not automatically retained from one input or output message to another. This parameter must be explicitly provided with each input message, or through the output MFS descriptors if the output message is processed by MFS.