accessing environment variable

[Stephan Hennig]

Hi,

what is the preferred way to access an environment variable from within
the .emacs file?

I want to avoid writing hard coded paths into my .emacs file that had to
be adjusted after each update of, e.g., gs.  I've found the getenv
function should do what I want:

> getenv is an interactive compiled Lisp function in `env.el'.
> (getenv variable)
>
> Get the value of environment variable variable.
> variable should be a string.  Value is nil if variable is undefined in
> the environment.  Otherwise, value is a string.
>
> This function consults the variable `process-environment'
> for its value.

Since environment variable GS_PROG points to the GhostScript binary,
i.e., is of the pattern "path\to\gs\gswin32c.exe", I've tried various
combinations (quoting, escaping and parenthesizing) of

(getenv GS_PROG)

but I always get an error

> Printing...
> apply: Searching for program: no such file or directory, (getenv GS_PROG)

or similar in the *Message* buffer.  It seems to me getenv isn't
executed, but treated literally in this context.  How do I correctly
refer to an environment variable here?

Best regards,
Stephan Hennig


Windows XP,
This is GNU Emacs 22.1.50.1 (i386-mingw-nt5.1.2600) of 2007-07-07 on
NEUTRINO

>From my .emacs:

;;
;; Emacs Customization
;;

(custom-set-variables
[...]
 '(ps-lpr-command "(getenv GS_PROG)")
[...]