Each REXX interpreter sets its own rules by what identifyidentifies the pool in which the environmental variables are named. In addition, each operation system (OS) has their own definition as well. This makes it problamatic in the acessing/acquiring of environmental variables. Most programmers know what REXX interpreter they are using, and furthermore, they also know what operating system they are writing the REXX program for, so most programmers hard-wire (explicitly code) the "access-name" of the system environmental variables into the program.