Final register contents

The routine must leave the register status as follows:

Registers 1–14:

Restored to entry contents

Register 15:

Return Code:

X'0': Processing successfully completed. The exit did not specify an ALS. Choose the ALS from the current list. If no entry in the current list is available for use, the session request should be routed to a cross-domain link.
X'4': The exit specified an ALS. However, if the specified ALS is not available for use, choose the ALS from the current list. If no entry in the current list is available for use, route the session request to a cross-domain link.
X'8': The exit did not specify an ALS. Choose the ALS from the current list. If no entry in the current list is available for use, do not route the session request to a subarea cross-domain link.
X'C': The exit specified an ALS. However, if the ALS is not available for use, choose the ALS from the current list. If no entry in the current list is available for use, do not route the session request to a subarea cross-domain link.
X'10': The exit specified an ALS. If the ALS is not available for use, do not choose the ALS from the current list and do not route the session request to a subarea cross-domain link.
X'14': The exit did not specify an ALS. Route the session request to a cross-domain link.
X'01'–X'7F': For other return code values, exit processing did not work. The session management exit remains active.

In addition to these specific return codes, there are other codes that control the exit's disablement. See Final register contents for more information about those codes.

Note: If the exit returns a return code that is not valid (that is, a return code not defined here), the session initiation request continues to be processed using the current ALS list specified to the exit routine. VTAM® issues message IST793E.

You can use the return codes to manipulate the processing of the ALS selection function. You can set a return code that causes VTAM to choose an ALS from the default list, choose the ALS returned in the ALS name information vector, or route the session cross-domain using a virtual route path. There are also return codes to handle cases where the selected ALS is unavailable.

VTAM does not perform ALS selection for an independent LU that is both the DLU and the PLU for the session. In that case, VTAM forwards the session request to an adjacent SSCP to locate the destination resource. Because VTAM does not drive ALS selection for such session requests, you cannot use the ALS return codes to affect routing for all resources. Instead, if you do not want the session request to be routed to a cross-domain link, you can use the initial authorization function described in Initial authorization function (function code X'00').