Quoting from OORexx 4.0 Reference: "USE ARG retrieves the argument objects provided in a program, routine, function, or method and
assigns them to variables or message term assignments.
Each name must be a valid variable name." This is very useful since it works for compound variables (stem variables) for calling and returning, plus it works for external procedures. This reduces the number of internal subroutines needed and allows reusable functions/subroutines.