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Date:      Wed, 29 May 2002 10:53:16 -0700
From:      Peter Wemm <peter@wemm.org>
To:        Poul-Henning Kamp <phk@critter.freebsd.dk>
Cc:        John Baldwin <jhb@FreeBSD.ORG>, Julian Elischer <julian@elischer.org>, FreeBSD current users <current@FreeBSD.ORG>
Subject:   Re: Seeking OK to commit KSE MIII 
Message-ID:  <20020529175316.1BC1438CC@overcee.wemm.org>
In-Reply-To: <430.1022694008@critter.freebsd.dk> 

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Poul-Henning Kamp wrote:
> In message <XFMail.20020529124710.jhb@FreeBSD.org>, John Baldwin writes:
> 
> >+       frame = td->td_frame;
> >+       frame->tf_eax = retval;         /* Child returns zero */
> >+       frame->tf_edx = aux;            /* I dunno */
> >
> >You could always ask about that instead of having a I dunno comment. :)
> >I think that we no longer use 2 return values from syscalls for FreeBSD
> >syscalls (I know we did for fork1() at one point, possibly still do
> >so that 4.x libc works ok on 5.x kernel).  Linux does depend on edx being
> >preserved across a syscall though IIRC.
> 
> We do for 64bit returns like lseek(2)

And also pipe(2) has a dual return from the syscall itself.  libc massages
this into something that C programs like.

Cheers,
-Peter
--
Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com
"All of this is for nothing if we don't go to the stars" - JMS/B5


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