Function

Queries and alters environment variables. The stem __environment. is not altered through this service. That stem contains the environment variables on entry to the REXX program, and is available for your use. Alterations of the environment are used on subsequent calls to the stream popen command and ADDRESS SH.

Parameters

variable name

The name of the environment variable to operate on. If this is the only argument specified, the value of the variable is returned and the variable is not affected.

new value

A string to replace the value of variable name. The previous value of the variable is returned.

operation

An optional argument that specifies the operation to be performed. Only the first character is significant. The values can be:

exists

Tests the existence of the variable. The function returns 1 if the variable is defined, and 0 if it is not defined.

delete

Deletes the variable from the environment, if it exists. The function returns 0 if the variable is successfully deleted, and 1 if the variable is not defined.