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| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Pointers, constant values |
| Date | 2015-10-16 21:07 +0100 |
| Organization | A noiseless patient Spider |
| Message-ID | <87io66r30y.fsf@bsb.me.uk> (permalink) |
| References | <5b2ab074-7644-4798-9b90-a3ae47e1f2b8@googlegroups.com> <ln4mhq7s4z.fsf@kst-u.example.com> <mvr9nb$ra4$1@dont-email.me> <ln8u726308.fsf@kst-u.example.com> <mvrjar$2ji$1@dont-email.me> |
Bartc <bc@freeuk.com> writes:
> On 16/10/2015 20:13, Keith Thompson wrote:
>> Bartc <bc@freeuk.com> writes:
>
>>> int array_sum(int (*array)[], int n);
>>
>> Yes, but there's not much you can do with it, since you haven't
>> specified the length of the array it points to. (I'm a little surprised
>> that that declaration is legal.)
>
> It's a pointer to an unbounded array.
It's a pointer to an incomplete array type and, as such, is compatible
with a pointer to an int array of any length. Talking about an
unbounded array in C sounds very odd to me (but I did know what you
mean).
In C99 there's no reason not to go the whole hog and write
int array_sum(int n, int (*data)[n]) { ... }
Now you *can* ask about sizeof *data, and even the usual ARRAY_SIZE
macro trick will work[1]. Of course the answer will be n, so there's
not much point, but then there was not much point in passing a pointer
to an array in the first place!
[1] I.e.
#define ARRAY_SIZE(a) (sizeof (a) / sizeof (a)[0])
--
Ben.
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Pointers, constant values Alla _ <modelling.data@gmail.com> - 2015-10-16 00:49 -0700
Re: Pointers, constant values Philip Lantz <prl@canterey.us> - 2015-10-16 01:49 -0700
Re: Pointers, constant values James Kuyper <jameskuyper@verizon.net> - 2015-10-16 09:41 -0400
Re: Pointers, constant values supercat@casperkitty.com - 2015-10-16 08:55 -0700
Re: Pointers, constant values Keith Thompson <kst-u@mib.org> - 2015-10-16 08:25 -0700
Re: Pointers, constant values supercat@casperkitty.com - 2015-10-16 09:11 -0700
Re: Pointers, constant values Keith Thompson <kst-u@mib.org> - 2015-10-16 12:06 -0700
Re: Pointers, constant values supercat@casperkitty.com - 2015-10-16 12:55 -0700
Re: Pointers, constant values Bartc <bc@freeuk.com> - 2015-10-16 17:49 +0100
Re: Pointers, constant values Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2015-10-16 13:23 -0400
Re: Pointers, constant values Bartc <bc@freeuk.com> - 2015-10-16 19:34 +0100
Re: Pointers, constant values supercat@casperkitty.com - 2015-10-16 12:05 -0700
Re: Pointers, constant values Keith Thompson <kst-u@mib.org> - 2015-10-16 12:18 -0700
Re: Pointers, constant values Keith Thompson <kst-u@mib.org> - 2015-10-16 12:13 -0700
Re: Pointers, constant values Bartc <bc@freeuk.com> - 2015-10-16 20:33 +0100
Re: Pointers, constant values Keith Thompson <kst-u@mib.org> - 2015-10-16 13:01 -0700
Re: Pointers, constant values Bartc <bc@freeuk.com> - 2015-10-16 21:09 +0100
Re: Pointers, constant values Keith Thompson <kst-u@mib.org> - 2015-10-16 13:41 -0700
Re: Pointers, constant values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-16 21:07 +0100
Re: Pointers, constant values Bartc <bc@freeuk.com> - 2015-10-16 21:20 +0100
Re: Pointers, constant values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-16 22:02 +0100
Re: Pointers, constant values Bartc <bc@freeuk.com> - 2015-10-16 22:21 +0100
Re: Pointers, constant values supercat@casperkitty.com - 2015-10-16 14:39 -0700
Re: Pointers, constant values Keith Thompson <kst-u@mib.org> - 2015-10-16 15:26 -0700
Re: Pointers, constant values supercat@casperkitty.com - 2015-10-16 15:44 -0700
Re: Pointers, constant values Keith Thompson <kst-u@mib.org> - 2015-10-16 16:58 -0700
Re: Pointers, constant values supercat@casperkitty.com - 2015-10-16 17:28 -0700
Re: Pointers, constant values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-16 22:50 +0100
Re: Pointers, constant values supercat@casperkitty.com - 2015-10-16 15:14 -0700
Re: Pointers, constant values Bartc <bc@freeuk.com> - 2015-10-17 01:23 +0100
Re: Pointers, constant values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-17 19:39 +0100
Re: Pointers, constant values Bartc <bc@freeuk.com> - 2015-10-17 22:42 +0100
Re: Pointers, constant values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-18 00:31 +0100
Re: Pointers, constant values Bartc <bc@freeuk.com> - 2015-10-18 02:11 +0100
Re: Pointers, constant values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-18 11:59 +0100
Re: Pointers, constant values Bartc <bc@freeuk.com> - 2015-10-18 12:12 +0100
Re: Pointers, constant values Bartc <bc@freeuk.com> - 2015-10-18 12:28 +0100
Re: Pointers, constant values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-18 23:16 +0100
Re: Pointers, constant values Bartc <bc@freeuk.com> - 2015-10-18 23:34 +0100
Re: Pointers, constant values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-19 01:45 +0100
Re: Pointers, constant values Bartc <bc@freeuk.com> - 2015-10-19 11:51 +0100
Re: Pointers, constant values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-19 12:55 +0100
Re: Pointers, constant values Bartc <bc@freeuk.com> - 2015-10-19 13:51 +0100
Re: Pointers, constant values Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-19 06:02 -0700
Re: Pointers, constant values supercat@casperkitty.com - 2015-10-19 07:02 -0700
Re: Pointers, constant values Bartc <bc@freeuk.com> - 2015-10-19 15:39 +0100
Re: Pointers, constant values supercat@casperkitty.com - 2015-10-19 08:54 -0700
Re: Pointers, constant values Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-19 09:14 -0700
Re: Pointers, constant values supercat@casperkitty.com - 2015-10-19 10:21 -0700
Re: Pointers, constant values Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-19 12:57 -0700
Re: Pointers, constant values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-19 21:20 +0000
Re: Pointers, constant values supercat@casperkitty.com - 2015-10-20 20:50 -0700
Re: Pointers, constant values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-21 04:58 +0000
Re: Pointers, constant values Keith Thompson <kst-u@mib.org> - 2015-10-19 08:40 -0700
Re: Pointers, constant values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-19 20:17 +0100
Re: Pointers, constant values supercat@casperkitty.com - 2015-10-17 16:44 -0700
Re: Pointers, constant values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-18 11:52 +0100
Re: Pointers, constant values Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-18 05:15 -0700
Re: Pointers, constant values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-18 21:54 +0100
Re: Pointers, constant values Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-18 16:09 -0700
Re: Pointers, constant values supercat@casperkitty.com - 2015-10-18 07:55 -0700
Re: Pointers, constant values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-18 21:47 +0100
Re: Pointers, constant values supercat@casperkitty.com - 2015-10-18 15:37 -0700
Re: Pointers, constant values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-19 00:10 +0100
Re: Pointers, constant values supercat@casperkitty.com - 2015-10-18 19:04 -0700
Re: Pointers, constant values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-16 21:13 +0100
Re: Pointers, constant values Ian Collins <ian-news@hotmail.com> - 2015-10-17 11:27 +1300
Re: Pointers, constant values Bartc <bc@freeuk.com> - 2015-10-17 00:56 +0100
Re: Pointers, constant values Les Cargill <lcargill99@comcast.com> - 2015-10-16 12:37 -0500
Re: Pointers, constant values James Kuyper <jameskuyper@verizon.net> - 2015-10-16 14:22 -0400
Re: Pointers, constant values Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-10-16 18:57 +0000
Re: Pointers, constant values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-16 20:40 +0100
Re: Pointers, constant values Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-10-16 20:46 +0000
Re: Pointers, constant values Keith Thompson <kst-u@mib.org> - 2015-10-16 14:24 -0700
Re: Pointers, constant values Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-10-19 12:43 +0000
Re: Pointers, constant values Siri Cruz <chine.bleu@yahoo.com> - 2015-10-16 13:20 -0700
Re: Pointers, constant values supercat@casperkitty.com - 2015-10-17 13:59 -0700
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