How Do CA Automation Point and REXX Communicate?

When CA Automation Point invokes a REXX program:

The REXX program issues standard REXX commands and commands available in other environments.
The commands interact with internal code in CA Automation Point; the code performs the low-level work required by each specific REXX function, and then returns control of the executing program to REXX.
CA Automation Point passes information back to REXX in the form of REXX variables, or puts the information on the external data queue.
The standard REXX commands in the REXX program process the new REXX variables.

The following illustration shows how information flows between CA Automation Point and REXX.