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Re: on why declare a struct with a single array in it

From Guillaume <message@bottle.org>
Newsgroups comp.lang.c
Subject Re: on why declare a struct with a single array in it
Date 2021-11-13 18:23 +0100
Organization Aioe.org NNTP Server
Message-ID <smosat$1qgm$1@gioia.aioe.org> (permalink)
References <86tughjjm7.fsf@levado.to> <slrnsouusf.1rfm.grahn+nntp@frailea.sa.invalid>

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Le 13/11/2021 à 09:47, Jorgen Grahn a écrit :
> On Fri, 2021-11-12, Meredith Montgomery wrote:
>> Because it's not like they can hide this array in the
>> structure; it's still referenced as
(...)
> There is no information hiding, but that's not a big problem IMO.  Or
> perhaps I have gotten used to it.

Actually, I didn't mention it, but encapsulating data in a struct does 
allow some form of "information hiding" - if we all mean the same thing 
here.

You can define "opaque" types using structs - more precisely, using 
pointers to structs. It's commonly seen in standard libraries, POSIX 
stuff, etc.

Of course, if you have access to the struct definition, there is no 
hiding per se, but you can absolutely distribute a library with only 
opaque data types for the user of the library.

'FILE *' is a common example. Do you ever care what is behind a FILE 
type? It often depends on the platform anyway. You only use it through a 
pointer.

What allows to hide what's inside a struct in C using pointers is the 
fact you can absolutely define a pointer to a struct without defining 
the struct itself:

typedef struct Foo * Foo_t;

As long as you don't need to directly access the underlying struct 
members, that works plenty fine - typical use is through function calls.

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Thread

on why declare a struct with a single array in it Meredith Montgomery <mmontgomery@levado.to> - 2021-11-12 15:48 -0300
  Re: on why declare a struct with a single array in it Guillaume <message@bottle.org> - 2021-11-12 19:56 +0100
    Re: on why declare a struct with a single array in it Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-11-12 19:31 +0000
      Re: on why declare a struct with a single array in it David Brown <david.brown@hesbynett.no> - 2021-11-12 21:07 +0100
        Re: on why declare a struct with a single array in it pozz <pozzugno@gmail.com> - 2021-11-18 15:53 +0100
          Re: on why declare a struct with a single array in it David Brown <david.brown@hesbynett.no> - 2021-11-18 16:13 +0100
            Re: on why declare a struct with a single array in it Manfred <noname@add.invalid> - 2021-11-18 16:26 +0100
              Re: on why declare a struct with a single array in it pozz <pozzugno@gmail.com> - 2021-11-18 17:22 +0100
                Re: on why declare a struct with a single array in it Manfred <noname@add.invalid> - 2021-11-18 18:04 +0100
                Re: on why declare a struct with a single array in it Meredith Montgomery <mmontgomery@levado.to> - 2021-11-19 16:00 -0300
                Re: on why declare a struct with a single array in it David Brown <david.brown@hesbynett.no> - 2021-11-18 22:58 +0100
                Re: on why declare a struct with a single array in it Guillaume <message@bottle.org> - 2021-11-19 17:53 +0100
                Re: on why declare a struct with a single array in it Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-11-19 11:27 -0800
                Re: on why declare a struct with a single array in it scott@slp53.sl.home (Scott Lurndal) - 2021-11-19 20:46 +0000
                Re: on why declare a struct with a single array in it Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-11-19 12:52 -0800
                Re: on why declare a struct with a single array in it David Brown <david.brown@hesbynett.no> - 2021-11-20 13:36 +0100
                Re: on why declare a struct with a single array in it Bart <bc@freeuk.com> - 2021-11-20 14:49 +0000
                Re: on why declare a struct with a single array in it Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-11-20 15:52 -0800
                Re: on why declare a struct with a single array in it Bart <bc@freeuk.com> - 2021-11-21 00:19 +0000
                Re: on why declare a struct with a single array in it Richard Damon <Richard@Damon-Family.org> - 2021-11-20 20:44 -0500
                Re: on why declare a struct with a single array in it David Brown <david.brown@hesbynett.no> - 2021-11-21 14:51 +0100
                Re: on why declare a struct with a single array in it Manfred <noname@add.invalid> - 2021-11-21 19:32 +0100
                Re: on why declare a struct with a single array in it David Brown <david.brown@hesbynett.no> - 2021-11-21 21:51 +0100
                Re: on why declare a struct with a single array in it Manfred <noname@add.invalid> - 2021-11-22 03:17 +0100
                Re: on why declare a struct with a single array in it David Brown <david.brown@hesbynett.no> - 2021-11-22 11:31 +0100
                Re: on why declare a struct with a single array in it Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2021-12-10 04:21 -0800
                Re: on why declare a struct with a single array in it David Brown <david.brown@hesbynett.no> - 2021-12-10 14:43 +0100
                Re: on why declare a struct with a single array in it Bart <bc@freeuk.com> - 2021-11-22 11:56 +0000
                Re: on why declare a struct with a single array in it Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-10 01:47 -0800
                Re: on why declare a struct with a single array in it Bart <bc@freeuk.com> - 2021-12-10 10:55 +0000
                Re: on why declare a struct with a single array in it David Brown <david.brown@hesbynett.no> - 2021-12-10 14:51 +0100
                Re: on why declare a struct with a single array in it Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-11 06:56 -0800
                Re: on why declare a struct with a single array in it Bart <bc@freeuk.com> - 2021-12-11 16:04 +0000
                Re: on why declare a struct with a single array in it Bart <bc@freeuk.com> - 2021-12-11 17:23 +0000
                Re: on why declare a struct with a single array in it Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-01-21 05:30 -0800
                Re: on why declare a struct with a single array in it Bart <bc@freeuk.com> - 2022-01-21 13:49 +0000
                Re: on why declare a struct with a single array in it "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-12-11 12:17 -0800
                Re: on why declare a struct with a single array in it gazelle@shell.xmission.com (Kenny McCormack) - 2021-12-12 13:00 +0000
                Re: on why declare a struct with a single array in it Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-12 08:25 -0800
                Re: on why declare a struct with a single array in it gazelle@shell.xmission.com (Kenny McCormack) - 2021-12-12 17:38 +0000
                Re: on why declare a struct with a single array in it Dick <thiebauddick2@aol.com> - 2021-12-12 16:19 -0500
                Re: on why declare a struct with a single array in it gazelle@shell.xmission.com (Kenny McCormack) - 2021-12-13 08:06 +0000
                Re: on why declare a struct with a single array in it Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2021-12-13 01:30 -0800
                Re: on why declare a struct with a single array in it David Brown <david.brown@hesbynett.no> - 2021-12-13 09:34 +0100
                Re: on why declare a struct with a single array in it Robert Latest <boblatest@yahoo.com> - 2021-12-13 18:53 +0000
                Re: on why declare a struct with a single array in it gazelle@shell.xmission.com (Kenny McCormack) - 2021-12-13 20:38 +0000
                Re: on why declare a struct with a single array in it Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-15 00:38 -0800
                Re: on why declare a struct with a single array in it gazelle@shell.xmission.com (Kenny McCormack) - 2021-12-15 11:21 +0000
                Re: on why declare a struct with a single array in it Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-15 10:26 -0800
                Re: on why declare a struct with a single array in it Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-15 10:45 -0800
                Re: on why declare a struct with a single array in it Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-10 10:52 -0800
                Re: on why declare a struct with a single array in it Guillaume <message@bottle.org> - 2021-11-22 04:06 +0100
                Re: on why declare a struct with a single array in it Bart <bc@freeuk.com> - 2021-11-22 11:32 +0000
                Re: on why declare a struct with a single array in it Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-11-22 13:00 -0800
                Re: on why declare a struct with a single array in it "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-11-21 13:08 -0800
                Re: on why declare a struct with a single array in it Richard Damon <Richard@Damon-Family.org> - 2021-11-20 20:44 -0500
                Re: on why declare a struct with a single array in it Bart <bc@freeuk.com> - 2021-11-21 12:22 +0000
                Re: on why declare a struct with a single array in it Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2021-11-20 20:13 -0700
                Re: on why declare a struct with a single array in it Bart <bc@freeuk.com> - 2021-11-21 12:35 +0000
                Re: on why declare a struct with a single array in it Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2021-11-21 10:53 -0700
                Re: on why declare a struct with a single array in it Bart <bc@freeuk.com> - 2021-11-21 18:49 +0000
                Re: on why declare a struct with a single array in it "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-11-21 13:04 -0800
                Re: on why declare a struct with a single array in it Bart <bc@freeuk.com> - 2021-11-21 14:42 +0000
                Re: on why declare a struct with a single array in it Guillaume <message@bottle.org> - 2021-11-21 01:34 +0100
                Re: on why declare a struct with a single array in it Bart <bc@freeuk.com> - 2021-11-21 00:48 +0000
                Re: on why declare a struct with a single array in it "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-11-20 16:58 -0800
                Re: on why declare a struct with a single array in it David Brown <david.brown@hesbynett.no> - 2021-11-21 14:40 +0100
                Re: on why declare a struct with a single array in it "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-11-21 12:59 -0800
                Re: on why declare a struct with a single array in it scott@slp53.sl.home (Scott Lurndal) - 2021-11-21 15:58 +0000
                Re: on why declare a struct with a single array in it gazelle@shell.xmission.com (Kenny McCormack) - 2021-11-20 10:55 +0000
  Re: on why declare a struct with a single array in it Jorgen Grahn <grahn+nntp@snipabacken.se> - 2021-11-13 08:47 +0000
    Re: on why declare a struct with a single array in it Guillaume <message@bottle.org> - 2021-11-13 18:23 +0100
  Re: on why declare a struct with a single array in it Kaz Kylheku <480-992-1380@kylheku.com> - 2021-11-13 17:55 +0000
  Re: on why declare a struct with a single array in it Anton Shepelev <anton.txt@g{oogle}mail.com> - 2021-11-19 13:14 +0300
    Re: on why declare a struct with a single array in it Meredith Montgomery <mmontgomery@levado.to> - 2021-11-19 16:07 -0300

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