From: Steve Nickolas <usotsuki@buric.co>
To: Doug McIlroy <doug@cs.dartmouth.edu>
Cc: tuhs@tuhs.org
Subject: Re: [TUHS] reviving a bit of WWB
Date: Sun, 20 Sep 2020 16:58:51 -0400 (EDT) [thread overview]
Message-ID: <alpine.DEB.2.21.2009201654300.10605@sd-119843.dedibox.fr> (raw)
In-Reply-To: <202009202026.08KKQ2x6137303@tahoe.cs.dartmouth.edu>
On Sun, 20 Sep 2020, Doug McIlroy wrote:
>> (Of course, that assumes NULL is 0, but I don't think I've run into any
>> architecture so braindead as to not have NULL=0.)
>
> It has nothing to do with machine architecture. The C standard
> says 0 coerces to the null pointer. NULL, defined in <stddef.h>,
> is part of the library, not the language. I always use 0,
> because NULL is a frill.
>
> Doug
I was under the impression that there was explicitly no requirement that a
null pointer be 0, and that there was at least one weird system where that
wasn't true - that it just so happened that null points to 0 on certain
CPUs and that 0=NULL *happens* to work on most CPUs but wasn't guaranteed.
(In fact, I read that my habit of using 0 for NULL relied on a faulty
assumption!)
I mean, I've never actually used a CPU/OS/compiler where it wasn't true,
but...
-uso.
next prev parent reply other threads:[~2020-09-20 20:59 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-19 1:51 Doug McIlroy
2020-09-20 18:42 ` arnold
2020-09-20 19:28 ` Will Senn
2020-09-20 20:12 ` Steve Nickolas
2020-09-20 20:26 ` Doug McIlroy
2020-09-20 20:57 ` Doug McIlroy
2020-09-20 22:13 ` Clem Cole
2020-09-21 20:43 ` Steffen Nurpmeso
2020-09-20 20:58 ` Steve Nickolas [this message]
2020-09-20 21:33 ` Brantley Coile
2020-10-07 5:43 ` scj
2020-09-20 21:35 ` John Cowan
2021-02-02 23:08 ` Greg A. Woods
2021-02-02 23:47 ` Larry McVoy
2021-02-03 0:11 ` Dave Horsfall
2021-02-03 0:19 ` Larry McVoy
2021-02-03 2:04 ` Richard Salz
2021-02-03 3:32 ` Dave Horsfall
2021-02-03 4:32 ` M Douglas McIlroy
2021-02-03 11:27 ` Peter Jeremy via TUHS
2021-02-03 20:09 ` Dave Horsfall
2021-02-03 20:13 ` Niklas Karlsson
2021-02-03 23:46 ` Tom Lyon
2021-02-03 22:19 ` Dave Horsfall
2021-02-03 22:55 ` M Douglas McIlroy
2020-09-20 22:15 ` Clem Cole
2020-09-20 22:47 ` John Cowan
2020-09-21 20:48 ` Steffen Nurpmeso
2020-09-21 20:46 ` Steffen Nurpmeso
2020-09-24 2:25 ` Dave Horsfall
2020-09-24 2:33 ` Clem Cole
2020-09-25 0:18 ` [TUHS] One's complement (was: reviving a bit of WWB) Greg 'groggy' Lehey
2020-09-25 0:22 ` Warner Losh
2020-09-25 1:39 ` John Cowan
2020-09-27 5:54 ` [TUHS] reviving a bit of WWB Dave Horsfall
2020-09-24 17:19 ` Paul Winalski
2020-09-24 18:17 ` John Cowan
2020-10-07 5:47 ` scj
2020-10-07 9:20 ` arnold
2020-10-08 0:27 ` Dave Horsfall
2020-10-08 3:08 ` John Cowan
2020-09-20 22:51 Norman Wilson
2020-09-20 23:00 Norman Wilson
2020-09-20 23:53 ` Clem Cole
2020-09-21 0:00 ` Clem Cole
2020-09-21 2:24 ` John Cowan
2020-09-21 0:09 ` Warner Losh
2020-09-21 1:05 ` Clem Cole
2020-09-21 5:55 ` Steve Nickolas
2020-09-21 5:59 ` Warner Losh
2020-09-21 18:40 ` Paul Winalski
2020-09-21 19:56 ` Dan Cross
2020-09-21 20:50 ` John Cowan
2020-09-21 21:22 ` Rob Pike
2020-09-21 21:57 ` Clem Cole
2020-09-21 23:56 ` John Cowan
2020-09-22 0:54 ` Richard Salz
2020-09-21 21:39 ` Steve Nickolas
2020-09-25 14:19 Doug McIlroy
2020-09-28 17:35 ` Angelo Papenhoff
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=alpine.DEB.2.21.2009201654300.10605@sd-119843.dedibox.fr \
--to=usotsuki@buric.co \
--cc=doug@cs.dartmouth.edu \
--cc=tuhs@tuhs.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).