Anchor support

The Language Environment anchor is the address of its main control block, the CAA. There is one CAA per thread, and the CAA is created during thread initialization. When the address of the anchor is unknown to the executing routine, it must be obtained. This usually occurs when an old routine calls a newly compiled, Language Environment-enabled routine. Upon entry into the new routine, the Language Environment anchor service must be able to return the Language Environment anchor using the same sequence of code regardless of the environment under which the application is executing.

Under CICS®, one CAA exists per CICS run unit. Because multiple CICS run units can exist under one z/OS TCB, the TCB cannot directly hold the address of the CAA. However, the TCB can point to a code sequence that obtains the anchor.