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| From | BartC <bc@freeuk.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: pointers |
| Date | 2016-10-26 20:30 +0100 |
| Organization | A noiseless patient Spider |
| Message-ID | <nur07o$l02$1@dont-email.me> (permalink) |
| References | (18 earlier) <nuq549$dp9$1@dont-email.me> <lnoa276qow.fsf@kst-u.example.com> <nuqq5u$sas$1@dont-email.me> <0111c223-4f39-4649-9cbc-387ca701d62c@googlegroups.com> <nuqv5h$gs7$1@dont-email.me> |
On 26/10/2016 20:12, BartC wrote:
> On 26/10/2016 19:44, supercat@casperkitty.com wrote:
>> but that would uselessly accept things that weren't pointers to pointers.
>> If & and * operatons could be nested, that would allow
>>
>> #define try_resize(p,size) try_resize ((void**)& &**(p),(size))
> (However, as I deal with chains of & and * in my non-C compiler, all
> matched & and * pairs will be eliminated before type-checking is done.
> So it couldn't be used for that kind of validation.)
That's not quite right: while * (or its equivalent) has to look 'behind'
to see if there is a & which may affect it, that isn't the case with &
which only looks forwards.
So in C:
int A;
enum {B};
*&A; // valid
*&B; // not valid
If you needed A or B to be lvalues, you can't tell just by looking at A;
or B; in the source. But *&A; or *&B; will guard that without affecting
the value.
Probably there are better examples...
But it shows that allowing chains of & and * can't hurt.
--
Bartc
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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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