Path: csiph.com!optima2.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!1.eu.feeder.erje.net!news.swapon.de!eternal-september.org!feeder.eternal-september.org!mx02.eternal-september.org!.POSTED!not-for-mail
From: Keith Thompson <kst-u@mib.org>
Newsgroups: comp.lang.c
Subject: Re: Programming openssl
Date: Mon, 03 Aug 2015 12:24:15 -0700
Organization: None to speak of
Lines: 39
Message-ID: <lny4hsgops.fsf@kst-u.example.com>
References: <mpimqv$32d$1@ns2.nl2k.ab.ca> <55bce017.8665140@news.xs4all.nl> <lnvbcykbiu.fsf@kst-u.example.com> <55be93b8.1078968@news.xs4all.nl>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Injection-Info: mx02.eternal-september.org; posting-host="945944de09706c9b4e29b53c9d2efdc2"; logging-data="10364"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX1/5VDJ88+XvppPrNAaEQke8"
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux)
Cancel-Lock: sha1:gZGD6OsuMPqMM3Sb+qyl59jcYYo= sha1:SIH3S9KuPxy6EgrMH2bgDzJsQkQ=
Xref: csiph.com comp.lang.c:66810

raltbos@xs4all.nl (Richard Bos) writes:
> Keith Thompson <kst-u@mib.org> wrote:
>> raltbos@xs4all.nl (Richard Bos) writes:
>> > doctor@doctor.nl2k.ab.ca (The Doctor) wrote:
>> >
>> >> getenv.o(.text+0x65): undefined reference to `environ'
>> >> getenv.o(.text+0x72): undefined reference to `environ'
>> >
>> >> What do I need to fix this problem?
>> >
>> > Build this program using an implementation which defines "environ". IIRC
>> > this is POSIX, but I may be wrong and it could be Ganuck; in any case,
>> > your code should use <unistd.h>, and I'm surprised that it doesn't
>> > already.
>> 
>> FYI, "Ganuck" is Richard's silly nickname for GNU.
>
> And I still don't know whether environ is GNUbile or POSIX, despite you
> and all other GNUheads being perfectly capable of adding that
> information.
>
> Embrace and extend, embrace and extend.

environ is defined by POSIX.
http://pubs.opengroup.org/onlinepubs/9699919799/functions/environ.html

Looking back at the original article, I'm not sure why you think the
OP's code needs to use <unistd.h>.  Environ is not declared in
<unistd.h>; you need to declare it yourself as:

    extern char **environ;

(I can't think of any good reason for that, but that's the way it is.)

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"