User authorization processing

After a dependent region connection has been established, a signon process is performed to inform the external subsystem of the user ID associated with the IMS transaction being processed by the region. IMS activates a Signon exit routine provided by the external subsystem for this purpose. This initial signon for the region must be successful in order for a thread to be created for the application.

Signon processing can occur again during application program execution (that is, after the thread has been created). The Signon exit routine is activated for each message processed by the application program. The initial signon performed after the dependent region identify is related to the first message processed by the application (first get unique call to the message queue). Each subsequent message processed causes the Signon exit routine to be activated again to pass the new user ID. In the case of multiple mode transactions, this means that multiple signons can occur without intervening commit processing.

The external subsystem supplies a Signoff exit routine which IMS activates before terminating the dependent region connection. In the case of multiple signons for an application, signoff processing does not precede a new signon for a new message. A new signon rather replaces the previous.