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| Path | csiph.com!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail |
|---|---|
| From | Keith Thompson <kst-u@mib.org> |
| Newsgroups | comp.lang.c |
| Subject | Re: pointers |
| Date | Tue, 25 Oct 2016 17:35:35 -0700 |
| Organization | None to speak of |
| Lines | 48 |
| Message-ID | <lnwpgw6j6w.fsf@kst-u.example.com> (permalink) |
| References | <eddd93ef-a47b-4400-9b0b-d936ffffe329@googlegroups.com> <nuikqj$sja$2@dont-email.me> <18d7b7b9-ea72-49d3-9535-df13d560473c@googlegroups.com> <726d78eb-47b3-1b92-0203-e2f63bb740ae@verizon.net> <nujilm$4tg$1@dont-email.me> <ln7f8yd20j.fsf@kst-u.example.com> <nukp62$tfg$1@dont-email.me> <lnpompbvcj.fsf@kst-u.example.com> <nulcl7$sr1$1@dont-email.me> <lneg35bsfq.fsf@kst-u.example.com> <nulfjf$qgb$1@dont-email.me> <ln60ohblkv.fsf@kst-u.example.com> <nulp42$nqg$1@dont-email.me> <lnshrla4et.fsf@kst-u.example.com> <num3c9$jso$1@dont-email.me> <lnlgxc88q0.fsf@kst-u.example.com> <nuol16$idr$1@dont-email.me> <lnd1io8354.fsf@kst-u.example.com> <nuopn1$57r$1@dont-email.me> <ln4m408048.fsf@kst-u.example.com> <nuorqb$a9j$1@dont-email.me> |
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BartC <bc@freeuk.com> writes:
> On 26/10/2016 00:44, Keith Thompson wrote:
>> BartC <bc@freeuk.com> writes:
>>> I don't think like that at all. I just use & either to get the address
>>> of a storage location designated by an expression, or to offset a
>>> pointer operation. I don't care what the standard says!
>>
>> I suggest that's why you have such difficulty understanding or accepting
>> the actual rules. You think `& &*foo` makes some kind of sense, and you
>> refuse to accept the reasonably straightforward reasons that it doesn't.
>
> Yet if the Standard had slightly different wording, then suddenly it
> would make sense to you as well! But we'd be dealing with exactly the
> same objects and operations.
>
>>> I'm not that bothered what language it is either. When you're dealing
>>> with explicit pointers then the issues of applying address-of or
>>> dereferencing pointers are universal.
>>
>> Not really. Applying address-of makes sense only when there's an object
>> whose address you want.
>
> Well in your example of '& &*foo' I'd say that reduces to '&foo' due to
> the &* cancelling each other. So we have the address of the object foo.
> Perfectly reasonable.
>
> But the small-print in the C standard says that even though the &* in
> &*foo cancels to result in just foo, you can't apply the second & to
> '&*foo' as you can with 'foo' itself.
>
> You must see that it is the wording in that document that stops this
> construct being legal, rather than anything wrong with the universal
> ideas involved with this pointer and address manipulation.
>
> I think even Ben Bacarisse agreed with me that the Standard could easily
> have had a somewhat different rule, where &* elimination was applied
> recursively, that would have made & &*foo legal.
You're wrong on several points. I will explain further if and only if
you (1) answer the question I asked you before (the choices were (a),
(b), and (c)) *and* (2) you directly ask me to explain. Or you can just
continue to be wrong.
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
pointers asetofsymbols@gmail.com - 2016-10-23 08:11 -0700
Re: pointers Richard Heathfield <rjh@cpax.org.uk> - 2016-10-23 16:26 +0100
Re: pointers asetofsymbols@gmail.com - 2016-10-23 10:35 -0700
Re: pointers Ike Naar <ike@iceland.freeshell.org> - 2016-10-23 17:47 +0000
Re: pointers asetofsymbols@gmail.com - 2016-10-25 12:55 -0700
Re: pointers "James R. Kuyper" <jameskuyper@verizon.net> - 2016-10-23 13:58 -0400
Re: pointers BartC <bc@freeuk.com> - 2016-10-24 00:55 +0100
Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-23 17:27 -0700
Re: pointers BartC <bc@freeuk.com> - 2016-10-24 11:53 +0100
Re: pointers supercat@casperkitty.com - 2016-10-24 07:29 -0700
Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 08:55 -0700
Re: pointers Tim Rentsch <txr@alumni.caltech.edu> - 2016-10-24 14:02 -0700
Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 14:42 -0700
Re: pointers Tim Rentsch <txr@alumni.caltech.edu> - 2016-10-25 08:56 -0700
Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 12:17 -0700
Re: pointers Tim Rentsch <txr@alumni.caltech.edu> - 2016-10-26 06:37 -0700
Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 08:49 -0700
Re: pointers BartC <bc@freeuk.com> - 2016-10-24 17:25 +0100
Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 09:52 -0700
Re: pointers BartC <bc@freeuk.com> - 2016-10-24 18:15 +0100
Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 12:20 -0700
Re: pointers BartC <bc@freeuk.com> - 2016-10-24 20:58 +0100
Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 13:16 -0700
Re: pointers BartC <bc@freeuk.com> - 2016-10-24 23:53 +0100
Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 13:38 -0700
Re: pointers BartC <bc@freeuk.com> - 2016-10-25 23:06 +0100
Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 15:39 -0700
Re: pointers BartC <bc@freeuk.com> - 2016-10-26 00:26 +0100
Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 16:44 -0700
Re: pointers BartC <bc@freeuk.com> - 2016-10-26 01:02 +0100
Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 17:35 -0700
Re: pointers Ike Naar <ike@iceland.freeshell.org> - 2016-10-26 06:27 +0000
Re: pointers BartC <bc@freeuk.com> - 2016-10-26 12:47 +0100
Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-26 09:05 -0700
Re: pointers BartC <bc@freeuk.com> - 2016-10-26 18:46 +0100
Re: pointers supercat@casperkitty.com - 2016-10-26 11:44 -0700
Re: pointers BartC <bc@freeuk.com> - 2016-10-26 20:12 +0100
Re: pointers BartC <bc@freeuk.com> - 2016-10-26 20:30 +0100
Re: pointers supercat@casperkitty.com - 2016-10-26 13:02 -0700
Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-26 11:52 -0700
Re: pointers Ike Naar <ike@iceland.freeshell.org> - 2016-10-26 19:11 +0000
Re: pointers BartC <bc@freeuk.com> - 2016-10-26 21:25 +0100
Re: pointers "James R. Kuyper" <jameskuyper@verizon.net> - 2016-10-25 18:56 -0400
Re: pointers "James R. Kuyper" <jameskuyper@verizon.net> - 2016-10-25 19:12 -0400
Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 16:31 -0700
Re: pointers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-10-24 21:36 +0100
Re: pointers BartC <bc@freeuk.com> - 2016-10-25 16:54 +0100
Re: pointers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-10-25 19:09 +0100
Re: pointers supercat@casperkitty.com - 2016-10-24 11:33 -0700
Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 12:22 -0700
Re: pointers James Kuyper <jameskuyper@verizon.net> - 2016-10-24 10:23 -0400
Re: pointers "James R. Kuyper" <jameskuyper@verizon.net> - 2016-10-23 12:31 -0400
Re: pointers Richard Heathfield <rjh@cpax.org.uk> - 2016-10-23 17:38 +0100
Re: pointers Lorinczy Zsigmond <zsiga@nospam.for.me> - 2016-10-24 14:02 +0200
Re: pointers John Bode <jfbode1029@gmail.com> - 2016-10-24 13:34 -0700
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