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Message-ID: <003c01bfeef8$f17574d0$f7c723cb@lifelesswks>
From: "Robert Collins" <robert DOT collins AT itdomain DOT com DOT au>
To: "Dave Arnold" <avr_fan AT mailandnews DOT com>, "Mark Weaver" <mark AT npsl DOT co DOT uk>,
        "Cygwin" <cygwin AT sourceware DOT cygnus DOT com>
References: <003a01bfeef3$83f81340$50241004 AT homepc DOT freedsl DOT com>
Subject: Re: environ problem
Date: Sun, 16 Jul 2000 17:38:54 +1000
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AFAIK, putenv is _meant_ to alter the local environment..

http://www.erlenstar.demon.co.uk/unix/faq_2.html#SEC8

Rob
----- Original Message -----
From: "Dave Arnold" <avr_fan AT nettaxi DOT com>
To: "Mark Weaver" <mark AT npsl DOT co DOT uk>; "Cygwin" <cygwin AT sourceware DOT cygnus DOT com>
Sent: Sunday, July 16, 2000 4:50 PM
Subject: Re: environ problem


> I don't know a darn thing about POSIX but I do know that I tried using
> getenv() and also had access violations and other similar hangups.
>
> Do these functions work at all with cygwin?
>
> /dave
>
> -----Original Message-----
> From: Mark Weaver <mark AT npsl DOT co DOT uk>
> To: Cygwin <cygwin AT sourceware DOT cygnus DOT com>
> Date: Monday, July 10, 2000 8:12 AM
> Subject: environ problem
>
>
> >I am currently in the process of a sendmail port to NT, based on cygwin.
I
> >have discovered that sendmail internally modifies environ, and then uses
> >putenv to modify the resulting environment (sample code that I abstracted
> >attached below) - doing this causes cygwin compiled programs to crash
(due
> >in fact to an overwrite of the import address table).  (The crash might
not
> >be immediate; a number of putenv calls are sometimes required for the
> >appropriate chunk of memory to be overwritten).
> >
> >Before I `fix' this behaviour, does POSIX allow for modifying environ?
And
> >even if it doesn't, then is the practice widespread enough for it to be
> >worth supporting?  (i.e. should I fix cygwin or sendmail!)
> >
> >Thanks,
> >
> >Mark
> >
> >code snippet:
> >
> >int main()
> >{
> > char *emptyenviron[1];
> > char** ExternalEnviron;
> >
> > emptyenviron[0] = NULL;
> > ExternalEnviron = environ;
> > environ = emptyenviron;
> >
> > putenv("AGENT=sendmail"); // access violation here
> > return 1;
> >}
> >
> >
> >--
> >Want to unsubscribe from this list?
> >Send a message to cygwin-unsubscribe AT sourceware DOT cygnus DOT com
> >
>
>
> --
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>
>


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