Skip site navigation (1)Skip section navigation (2)
Date:      Tue, 15 Dec 1998 04:51:11 +0100
From:      Eivind Eklund <eivind@yes.no>
To:        Mike Smith <mike@smith.net.au>
Cc:        cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG
Subject:   Re: cvs commit: src/sys/i386/isa labpc.c
Message-ID:  <19981215045111.B46780@follo.net>
In-Reply-To: <199812150119.RAA01309@dingo.cdrom.com>; from Mike Smith on Mon, Dec 14, 1998 at 05:19:28PM -0800
References:  <199812132325.PAA16418@freefall.freebsd.org> <199812150119.RAA01309@dingo.cdrom.com>

next in thread | previous in thread | raw e-mail | index | archive | help
On Mon, Dec 14, 1998 at 05:19:28PM -0800, Mike Smith wrote:
> > eivind      1998/12/13 15:25:29 PST
> > 
> >   Modified files:
> >     sys/i386/isa         labpc.c 
> >   Log:
> >   Fix typo - sizeof(struct crtl *) -> sizeof(struct ctrl *).
> >   
> >   XXX This still assume that bzero() over a field create null-pointers,
> >   which seems a chancy proposition at best.
> 
> This is assumed by many portions of the kernel; you're welcome to point 
> out a system where we're likely to run and on which this isn't a valid 
> assumption.

We could e.g. want to run on segmented setup with NULL-pointers not
equal to bitwise zero.

However, if we are to assume that NULL pointers are all-bits-zero -
where would we document this?  Is there _any_ available document
saying which assumptions we make WRT portability?  If there isn't and
nobody step forward to make one, I'm going to keep using ANSI C as my
goal, and consider it a Bad Thing whenever something break it.

> You might also want to consider it in the context of my last comment 
> about structure field initialisers...

Oh, the ones our compiler have to support because they're used all of
10 or so places in the kernel?  (I've run verifiers that _screams_
when these are used and gone through all their output over the last
week - we don't have that many parts where structure field
initializers or union initializers are used, though the abuse in
sys/dev/ppbus/ and sys/i386/i386/userconfig.c does pull up the
instance-count pretty heftily.)

Eivind.

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe cvs-all" in the body of the message



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?19981215045111.B46780>