Environment variables are text strings in the form VNAME=value, where VNAME is the name of the variable and value is its value. The stem variables __argv and __environment are always set to the original values passed to the first-level REXX program, and they are visible to external REXX functions. You may want to use PARSE ARG instead of the __argv stem in external REXX programs. As the following two sample programs show, using the __argv stem from an external exec returns the same data as it did from the initial exec. In order for an external REXX program to get the arguments a caller is sending it, it must use arg() or PARSE ARG: