From: John Cowan <cowan@ccil.org>
To: Clem Cole <clemc@ccc.com>
Cc: The Eunuchs Hysterical Society <tuhs@tuhs.org>,
Doug McIlroy <doug@cs.dartmouth.edu>
Subject: Re: [TUHS] reviving a bit of WWB
Date: Sun, 20 Sep 2020 18:47:23 -0400 [thread overview]
Message-ID: <CAD2gp_SV19s6yHsdApn8Rfkgb3OZCVFdd++_MWTsX5b7c_Jbig@mail.gmail.com> (raw)
In-Reply-To: <CAC20D2OyFD4Z=4BByrj4OfNmHP1Z6uhS7S3jsQ4ba6jrHnQ+oQ@mail.gmail.com>
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The confusion (I dare not call it a flame war) is arising out of the
difference between an object with all bits zero and a 0 constant (or
equivalently 2*0 or 3-3 or what not). 0 in pointer context is always a
null pointer, but it may or may not be all-bits-zero. 0 in integer context
is, on any sane machine, all-bits-zero (on 1's-complement machines it may
also be all-bits-one).
Personally, when I was programming in C I defined a macro #define
NULLPTR(t) ((t)0), so that I would write NULLPTR(char *) or NULLPTR(int *)
or whatever the Right Thing was.
On Sun, Sep 20, 2020 at 6:16 PM Clem Cole <clemc@ccc.com> wrote:
>
>
> On Sun, Sep 20, 2020 at 4:59 PM Steve Nickolas <usotsuki@buric.co> wrote:
>
>> I was under the impression that there was explicitly no requirement that
>> a
>> null pointer be 0,
>>
> Indeed, section 7.19 states it is *implementation-defined*. See my
> previous message.
>
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next prev parent reply other threads:[~2020-09-20 22:48 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
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 [this message]
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
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