getenv behavior or bug

getenv behavior or bug

[Thierry Volpiatto]

Hi,
(getenv "HOSTNAME") returns nil both on 23 and 24 branch, is this normal
or a bug?

In M-x shell, echo $HOSTNAME returns what expected, idem for uname -n.

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Re: getenv behavior or bug

[Andreas Schwab]

Thierry Volpiatto <thierry.volpiatto@gmail.com> writes:

> (getenv "HOSTNAME") returns nil both on 23 and 24 branch, is this normal
> or a bug?

Does Emacs's environment include an entry for HOSTNAME?

Andreas.

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Re: getenv behavior or bug

[Harald Hanche-Olsen]

[Thierry Volpiatto <thierry.volpiatto@gmail.com> (2011-02-28 16:25:56 UTC)]

> (getenv "HOSTNAME") returns nil both on 23 and 24 branch, is this
> normal or a bug?

Emacs doesn't try to set this environment variable if it is not
already set. So presumably whatever process you use to start your
emacs from doesn't have it.

> In M-x shell, echo $HOSTNAME returns what expected, idem for uname -n.

I guess that is done somewhere in your shell startup files, or maybe
the global one. M-x shell runs a login shell after all.

- Harald

Re: getenv behavior or bug

[Thierry Volpiatto]

Harald Hanche-Olsen <hanche@math.ntnu.no> writes:

> [Thierry Volpiatto <thierry.volpiatto@gmail.com> (2011-02-28 16:25:56 UTC)]
>
>> (getenv "HOSTNAME") returns nil both on 23 and 24 branch, is this
>> normal or a bug?
>
> Emacs doesn't try to set this environment variable if it is not
> already set. So presumably whatever process you use to start your
> emacs from doesn't have it.
Thanks for answer,
So what's the environment variables emacs set on startup?

>> In M-x shell, echo $HOSTNAME returns what expected, idem for uname -n.
>
> I guess that is done somewhere in your shell startup files, or maybe
> the global one. M-x shell runs a login shell after all.
>
> - Harald

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Re: getenv behavior or bug

[Harald Hanche-Olsen]

[Thierry Volpiatto <thierry.volpiatto@gmail.com> (2011-02-28 18:03:13 UTC)]

> Thanks for answer,
> So what's the environment variables emacs set on startup?

Not very many. Perhaps none. You can find out yourself: Just run

  env - /usr/bin/emacs -q --batch --eval '(pp process-environment)'

from the command line. Replace /usr/bin/emacs by the absolute path to
your emacs; with an empty environment, the emacs executable can't be
found outherwise. The standard emacs on one ubuntu system I have
access to, prints just nil in response. (If I redirect stderr to
/dev/null that is.)

- Harald

Re: getenv behavior or bug

[Thierry Volpiatto]

Harald Hanche-Olsen <hanche@math.ntnu.no> writes:

> [Thierry Volpiatto <thierry.volpiatto@gmail.com> (2011-02-28 18:03:13 UTC)]
>
>> Thanks for answer,
>> So what's the environment variables emacs set on startup?
>
> Not very many. Perhaps none. You can find out yourself: Just run
>
>   env - /usr/bin/emacs -q --batch --eval '(pp process-environment)'
>
> from the command line. Replace /usr/bin/emacs by the absolute path to
> your emacs; with an empty environment, the emacs executable can't be
> found outherwise. The standard emacs on one ubuntu system I have
> access to, prints just nil in response. (If I redirect stderr to
> /dev/null that is.)
Yes, i have nil also on ubuntu. (with and without redirecting stderr to
/dev/null)

Thanks for this info about process-environment.

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Re: getenv behavior or bug

[Thierry Volpiatto]

Harald Hanche-Olsen <hanche@math.ntnu.no> writes:

> [Thierry Volpiatto <thierry.volpiatto@gmail.com> (2011-02-28 18:03:13 UTC)]
>
>> Thanks for answer,
>> So what's the environment variables emacs set on startup?
>
> Not very many. Perhaps none. You can find out yourself: Just run
>
>   env - /usr/bin/emacs -q --batch --eval '(pp process-environment)'
>
> from the command line. Replace /usr/bin/emacs by the absolute path to
> your emacs; with an empty environment, the emacs executable can't be
> found outherwise. The standard emacs on one ubuntu system I have
> access to, prints just nil in response. (If I redirect stderr to
> /dev/null that is.)

For a final note, just found that `system-name' return $HOSTNAME, it is
used by `emacs-version'.

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