Re: A portable stack in C

From	jacob navia <jacob@spamsink.net>
Newsgroups	comp.lang.c
Subject	Re: A portable stack in C
Date	2011-11-15 12:57 +0100
Organization	lccwin
Message-ID	<j9tk3s$7bl$1@speranza.aioe.org> (permalink)
References	(1 earlier) <j3r3c7tl1v45qjvee173t8759n1074h4ll@4ax.com> <j9t7gd$45e$1@speranza.aioe.org> <j9tdlo$669$1@dont-email.me> <j9temn$o6u$1@speranza.aioe.org> <0.ef2e570d4fa8ea6e44a0.20111115114550GMT.871ut9vcb5.fsf@bsb.me.uk>

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Le 15/11/11 12:45, Ben Bacarisse a écrit :
> jacob navia<jacob@spamsink.net>  writes:
> <snip>
>> Conceptually ANY pointer is an index in a big array called "memory"
>> (or RAM if you like).
>
> C pointers don't fit this concept.  They have a type which contributes
> to the result of operations like *p, sizeof *p and p + 1.
>

The *p operation is just
1) Read the value of the pointer
2) Index the memory
3) read that position.

This is just memory[p] (assuming non segmented memory)

sizeof(*p) <==> sizeof (memory[p]) where you would have
conceptually "memory" as an aray of *p.

The "p + 1" operation is the same:
memory[p+1] where "memory" is an array of objects of type *p.

> C's function pointers don't fit well into the "memory index" model
> either because you can do any array-like operations with them.
>

Function pointers can be emulated as a conceptual table of
machine instructions where p points to the start of the
sequence of instructions of a function.

In general, what I want to emphasize is the equivalence between array
indices and pointers.

And no, pleeze, I do not want to eliminate pointers from C... :-)

Thread

A portable stack in C "io_x" <a@b.c.invalid> - 2011-11-14 17:54 +0100
  Re: A portable stack in C Barry Schwarz <schwarzb@dqel.com> - 2011-11-14 20:55 -0800
    Re: A portable stack in C jacob navia <jacob@spamsink.net> - 2011-11-15 09:22 +0100
      Re: A portable stack in C Ike Naar <ike@iceland.freeshell.org> - 2011-11-15 09:00 +0000
        Re: A portable stack in C jacob navia <jacob@spamsink.net> - 2011-11-15 11:26 +0100
      Re: A portable stack in C "BartC" <bc@freeuk.com> - 2011-11-15 10:05 +0000
        Re: A portable stack in C jacob navia <jacob@spamsink.net> - 2011-11-15 11:25 +0100
          Re: A portable stack in C "BartC" <bc@freeuk.com> - 2011-11-15 11:08 +0000
          Re: A portable stack in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-11-15 11:45 +0000
            Re: A portable stack in C jacob navia <jacob@spamsink.net> - 2011-11-15 12:57 +0100
              Re: A portable stack in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-11-15 12:39 +0000
                Re: A portable stack in C jacob navia <jacob@spamsink.net> - 2011-11-15 14:26 +0100
                Re: A portable stack in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-11-15 15:31 +0000
                Re: A portable stack in C Keith Thompson <kst-u@mib.org> - 2011-11-15 12:53 -0800
                Re: A portable stack in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-11-15 21:15 +0000
                Re: A portable stack in C Keith Thompson <kst-u@mib.org> - 2011-11-15 14:29 -0800
                Re: A portable stack in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-11-15 22:59 +0000
                Re: A portable stack in C James Kuyper <jameskuyper@verizon.net> - 2011-11-15 17:30 -0500
                Re: A portable stack in C Willem <willem@toad.stack.nl> - 2011-11-15 22:33 +0000
                Re: A portable stack in C Keith Thompson <kst-u@mib.org> - 2011-11-15 15:07 -0800
                Re: A portable stack in C Seebs <usenet-nospam@seebs.net> - 2011-11-15 22:37 +0000
                Re: A portable stack in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-11-15 23:01 +0000
              Re: A portable stack in C "BartC" <bc@freeuk.com> - 2011-11-15 18:45 +0000
            Re: A portable stack in C Keith Thompson <kst-u@mib.org> - 2011-11-15 12:41 -0800
          Re: A portable stack in C Richard Damon <news.x.richarddamon@xoxy.net> - 2011-11-15 23:07 -0500
            Re: A portable stack in C Keith Thompson <kst-u@mib.org> - 2011-11-15 20:18 -0800
            Re: A portable stack in C Robert Wessel <robertwessel2@yahoo.com> - 2011-11-15 22:53 -0600
              Re: A portable stack in C "BartC" <bc@freeuk.com> - 2011-11-16 12:00 +0000
                Re: A portable stack in C falk@rahul.net (Edward A. Falk) - 2011-11-16 16:08 +0000
              Re: A portable stack in C David Thompson <dave.thompson2@verizon.net> - 2012-01-19 02:41 -0500
      Re: A portable stack in C Thomas David Rivers <rivers@dignus.com> - 2011-11-15 11:21 -0500
      Re: A portable stack in C Barry Schwarz <schwarzb@dqel.com> - 2011-11-15 17:53 -0800
    Re: A portable stack in C "io_x" <a@b.c.invalid> - 2011-11-15 19:21 +0100
      Re: A portable stack in C Barry Schwarz <schwarzb@dqel.com> - 2011-11-15 17:53 -0800
        Re: A portable stack in C "io_x" <a@b.c.invalid> - 2011-11-18 08:13 +0100
  Re: A portable stack in C Rui Maciel <rui.maciel@gmail.com> - 2011-11-15 10:14 +0000
    Re: A portable stack in C "io_x" <a@b.c.invalid> - 2011-11-15 19:20 +0100
  Re: A portable stack in C Acid Washed China Blue Jeans <chine.bleu@yahoo.com> - 2011-11-15 08:13 -0800
  Re: A portable stack in C Kaz Kylheku <kaz@kylheku.com> - 2011-11-15 16:27 +0000
    Re: A portable stack in C "io_x" <a@b.c.invalid> - 2011-11-15 19:21 +0100
    Re: A portable stack in C Keith Thompson <kst-u@mib.org> - 2011-11-15 13:19 -0800
  Re: A portable stack in C blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-11-17 15:45 +0000
    Re: A portable stack in C John Gordon <gordon@panix.com> - 2011-11-17 15:56 +0000
    Re: A portable stack in C "io_x" <a@b.c.invalid> - 2011-11-17 18:02 +0100
      Re: A portable stack in C "BartC" <bc@freeuk.com> - 2011-11-17 17:35 +0000
        Re: A portable stack in C Vincenzo Mercuri <vincenzo.mercuri@yahoo.it> - 2011-11-17 18:45 +0100
        Re: A portable stack in C Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-11-18 00:27 -0800
          Re: A portable stack in C "io_x" <a@b.c.invalid> - 2011-11-18 10:40 +0100
            Re: A portable stack in C "io_x" <a@b.c.invalid> - 2011-11-20 07:22 +0100
            Re: A portable stack in C Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-11-21 00:38 -0800
              Re: A portable stack in C "Jo" <none@none.none> - 2011-11-21 03:44 -0600
                Re: A portable stack in C Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-11-21 13:00 +0200
                Re: A portable stack in C "Jo" <none@none.none> - 2011-11-21 06:07 -0600
              Re: A portable stack in C "Jo" <none@none.none> - 2011-11-21 03:50 -0600
              Re: A portable stack in C "Jo" <none@none.none> - 2011-11-21 07:48 -0600
              Re: A portable stack in C "io_x" <a@b.c.invalid> - 2011-11-21 20:11 +0100
          Re: A portable stack in C "BartC" <bc@freeuk.com> - 2011-11-18 12:47 +0000
          Re: A portable stack in C "Jo" <none@none.none> - 2011-11-18 23:31 -0600
      Re: A portable stack in C blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-11-18 14:45 +0000
        Re: A portable stack in C James Kuyper <jameskuyper@verizon.net> - 2011-11-18 10:14 -0500
        Re: A portable stack in C Keith Thompson <kst-u@mib.org> - 2011-11-18 12:20 -0800
          Re: A portable stack in C blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-11-19 17:23 +0000
            Re: A portable stack in C Seebs <usenet-nospam@seebs.net> - 2011-11-19 18:49 +0000
              Re: A portable stack in C "Jo" <none@none.none> - 2011-11-19 22:41 -0600
              Re: A portable stack in C "io_x" <a@b.c.invalid> - 2011-11-20 07:27 +0100
                Re: A portable stack in C "io_x" <a@b.c.invalid> - 2011-11-21 20:12 +0100
            Re: A portable stack in C "io_x" <a@b.c.invalid> - 2011-11-20 07:50 +0100
          Re: A portable stack in C "Jo" <none@none.none> - 2011-11-21 01:24 -0600
            Re: A portable stack in C Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-11-21 05:22 -0800
              Re: A portable stack in C "Jo" <none@none.none> - 2011-11-22 03:31 -0600
  Re: A portable stack in C 88888 Dihedral <dihedral88888@googlemail.com> - 2011-11-21 06:38 -0800

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