Function

Summary

Reads the value of an environment variable from the environment table of the calling process.

Package

lispworks

Signature

environment-variable name => result

Arguments

name

A string.

Values

result

A string or nil .

Description

The function environment-variable reads the environment variable specified by name and returns its value, or nil if the variable could not be found.

A setf method is also defined, allowing you to set the value of an environment variable:

(setf (environment-variable name ) value )

If value is a string, then name is set to be value . If value is nil then name is removed from the environment table.

Example

In this first example the value of the environment variable PATH is returned:

(environment-variable "PATH")

The result is a string of all the defined paths:

"c:\\hqbin\\nt\\x86;c:\\hqbin\\nt\\x86\\perl;c:\\hqbin\\win32;c:\\usr\\local\\bin;C:\\WINNT35\\system32;C:\\WINNT35;;C:\\MSTOOLS\\bin;C:\\TGS3D\\PROGRAM;c:\\program files\\devstudio\\sharedide\\bin\\ide;c:\\program files\\devstudio\\sharedide\\bin;c:\\program files\\devstudio\\vc\\bin;c:\\msdev\\bin;C:\\WINDOWS;C:\\WINDOWS\\COMMAND;C:\\WIN95\\COMMAND;C:\\MSINPUT\\MOUSE"

In the second example, the variable MYTZONE is found not to be in the environment table:

(environment-variable "MYTZONE") NIL

It is set to be GMT using the setf method:

(setf (environment-variable "MYTZONE") "GMT")