Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.c > #384903

Re: Threads across programming languages

Path csiph.com!news.swapon.de!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups comp.lang.c
Subject Re: Threads across programming languages
Date Thu, 23 May 2024 08:54:35 -0700
Organization A noiseless patient Spider
Lines 76
Message-ID <86v834v804.fsf@linuxsc.com> (permalink)
References <GIL-20240429161553@ram.dialup.fu-berlin.de> <v0ogum$1rc5n$1@dont-email.me> <v0ovvl$1ur12$4@dont-email.me> <v0p06i$1uq6q$5@dont-email.me> <v0shti$2vrco$2@raubtier-asyl.eternal-september.org> <v0spsh$31ds4$3@dont-email.me> <v0stic$325kv$3@raubtier-asyl.eternal-september.org> <v0svtn$32o8h$1@dont-email.me> <v0t091$32qj6$1@raubtier-asyl.eternal-september.org> <v0u90h$3c1r5$4@dont-email.me> <v0v28q$3ku1r$1@raubtier-asyl.eternal-september.org> <v105sc$3skqi$1@dont-email.me> <v10adm$3to7r$1@raubtier-asyl.eternal-september.org> <v124a6$drbu$1@dont-email.me> <v125f4$e2kl$1@raubtier-asyl.eternal-september.org> <v12a4e$f4f1$2@dont-email.me> <v12hf0$gtpa$1@raubtier-asyl.eternal-september.org> <20240503180102.00002f98@yahoo.com> <86zfsnqhn6.fsf@linuxsc.com> <87fruely54.fsf@nosuchdomain.example.com>
MIME-Version 1.0
Content-Type text/plain; charset=us-ascii
Injection-Date Thu, 23 May 2024 17:54:37 +0200 (CEST)
Injection-Info dont-email.me; posting-host="e3ccaa8757308aabad5512a33960ab38"; logging-data="1927551"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19dr1+QRDU/93efOoF4JnJuEVgjv58gfrI="
User-Agent Gnus/5.11 (Gnus v5.11) Emacs/22.4 (gnu/linux)
Cancel-Lock sha1:uTPcTgwk6JxnA9odvpGOcelN060= sha1:2W7P9Ki+95xldsuuv4YGfl5iB3o=
Xref csiph.com comp.lang.c:384903

Show key headers only | View raw

Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:

> Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
> [...]
>
>> First, a pointer is not an object.  In both C and C++, any pointer,
>> including a function pointer, is a scalar value.  A pointer value
>> might be held in an object but it doesn't have to be.  In most cases
>> function pointers are not stored in objects but simply used to call
>> the function pointed to.
>
> [...]
>
> Certainly a pointer value is not an object.  Certainly a pointer
> object *is* an object.  It's not uncommon to informally refer to a
> pointer object as "a pointer".  I presume you would consider such
> usage to be incorrect, and I don't disagree, but it is fairly
> common.

Good usage will be precise and logically consistent, adhere to the
rules of normal English usage, and align with how terminology and
phrasing is used in the C standard.  On the flip side, it is best
to try to avoid phrasing that is haphazard, careless, confusing,
or sloppy.

I don't remember ever seeing the phrase "pointer object" used to
mean a pointer value, either informally or otherwise.  The C
standard does use the phrase "pointer object" in some places, but
it means something quite different from a pointer, namely, an
object that has pointer type (and not a pointer itself).  A local
declaration such as

   int *p;

introduces the identifier 'p' as (a way to designate) a pointer
object, but there is no pointer value anywhere in sight.

> I often find it useful to avoid referring to "pointers", and
> instead refer to "pointer types", "pointer values", "pointer
> objects", and so on (likewise for arrays).

I have the impression that you are someone who is unusually averse
to ambiguity.  I appreciate that your suggestions are given with
the idea that they will help with clarity of communication.
Unfortunately they don't always help, and sometimes make things
worse rather than better.  Your comment here is a case in point.
The C standard uses the word pointer (or pointers) in a little
over 900 places.  In most of those, pointer is used as a simple
noun;  whether in each case it refers to a type or a run-time
value is clear from context.  Notably, the C standard uses the
phrase "pointer value" in just a few places (I see five in n1570).
It seems clear that the Standard's use of this phrase is meant
to connote something different than just "pointer" by itself, and
also that this (rather rare) usage wasn't chosen by accident.  So
the rule you describe muddies the water rather than helping,
because it's not consistent with usage followed in the C standard.

> The C standard does not, as far as I can tell, provide a
> definition for the standalone term "pointer".  (I could have
> missed something;  I checked section 3, "Terms, definitions, and
> symbols", and the index.)  But the standard does, in several
> places, use the term "pointer" to refer to a pointer value.  I
> don't know whether it's consistent.

Yes, AFAICT the C standard doesn't define "pointer" as a standalone
noun.  But it is clear from context that "pointer" by itself means
basically the same thing as an address, as can be seen from the
description of unary &, in 6.5.3.2 p3, or in the second sentence
of the second paragraph of the footnote to 6.3.2.1 p1.

The C standard does, however, define the word "object" to mean
a region of storage in the execution environment.  Whatever it
is that a pointer might be, it's clear that it isn't a region
of storage in the execution environment.  The idea that a pointer
object might be a pointer, rather than an object, is nonsensical
on its face, and deserves to be called out as such.

Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

Re: Threads across programming languages Paavo Helde <eesnimi@osa.pri.ee> - 2024-04-29 19:13 +0300
  Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-04-29 20:29 +0000
    Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-04-29 13:33 -0700
      Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-04-29 22:41 +0000
        Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-04-29 16:46 -0700
          Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-04-30 00:11 +0000
      Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-01 06:54 +0200
        Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-01 07:10 +0000
          Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-01 10:13 +0200
            Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-01 08:53 +0000
              Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-01 10:59 +0200
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-01 20:34 +0000
                Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-02 05:45 +0200
                Re: Threads across programming languages David Brown <david.brown@hesbynett.no> - 2024-05-02 15:53 +0200
                Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-02 17:10 +0200
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-02 23:24 +0000
                Re: Threads across programming languages David Brown <david.brown@hesbynett.no> - 2024-05-03 09:38 +0200
                Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-03 09:58 +0200
                Re: Threads across programming languages David Brown <david.brown@hesbynett.no> - 2024-05-03 11:18 +0200
                Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-03 13:23 +0200
                Re: Threads across programming languages Michael S <already5chosen@yahoo.com> - 2024-05-03 18:01 +0300
                Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-03 17:18 +0200
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-03 22:20 +0000
                Re: Threads across programming languages Paavo Helde <eesnimi@osa.pri.ee> - 2024-05-04 20:41 +0300
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-05 01:41 +0000
                Re: Threads across programming languages Paavo Helde <eesnimi@osa.pri.ee> - 2024-05-05 10:38 +0300
                Re: Threads across programming languages Michael S <already5chosen@yahoo.com> - 2024-05-05 12:37 +0300
                Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-05 13:00 +0200
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-13 00:43 +0000
                Re: Threads across programming languages Michael S <already5chosen@yahoo.com> - 2024-05-13 15:04 +0300
                Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-13 16:52 +0200
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-17 22:18 +0000
                Re: Threads across programming languages Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-21 21:27 -0700
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-17 22:17 +0000
                Re: Threads across programming languages Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-15 08:53 -0700
                Re: Threads across programming languages Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-18 08:11 -0700
                Re: Threads across programming languages Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-05-18 12:26 -0700
                Re: Threads across programming languages Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-23 08:54 -0700
                Re: Threads across programming languages Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-05-23 16:31 -0700
                Re: Threads across programming languages Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-05-30 17:27 +0100
                Re: Threads across programming languages Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-05-30 14:21 -0700
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-02 23:21 +0000
                Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-03 08:45 +0200
                Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-03 09:05 +0200
                Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-03 09:09 +0200
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-04 02:33 +0000
                Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-03 20:05 -0700
                Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-03 20:07 -0700
                Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-03 20:09 -0700
                Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-04 06:00 +0200
                Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-03 21:19 -0700
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-05 01:40 +0000
                Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-04 22:23 -0700
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-02 05:39 +0000
                Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-02 07:53 +0200
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-02 23:16 +0000
                Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-03 09:00 +0200
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-04 02:30 +0000
                Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-03 20:36 -0700
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-04 04:46 +0000
                Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-03 21:50 -0700
                Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-04 06:00 +0200
                Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-03 21:27 -0700
                Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-02 13:28 -0700
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-02 23:15 +0000
                Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-02 16:58 -0700
                Re: Threads across programming languages Kaz Kylheku <643-408-1753@kylheku.com> - 2024-05-03 00:15 +0000
                Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-02 17:22 -0700
                Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-03 00:07 -0700
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-03 02:25 +0000
                Re: Threads across programming languages Ross Finlayson <ross.a.finlayson@gmail.com> - 2024-05-03 12:33 -0700
                Re: Threads across programming languages Ross Finlayson <ross.a.finlayson@gmail.com> - 2024-05-07 20:48 -0700
                Re: Threads across programming languages David Brown <david.brown@hesbynett.no> - 2024-05-03 10:34 +0200
                Re: Threads across programming languages Michael S <already5chosen@yahoo.com> - 2024-05-03 18:05 +0300
                Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-03 17:20 +0200
                Re: Threads across programming languages Michael S <already5chosen@yahoo.com> - 2024-05-03 18:47 +0300
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-03 22:19 +0000
                Re: Threads across programming languages bart <bc@freeuk.com> - 2024-05-04 00:27 +0100
                Re: Threads across programming languages Michael S <already5chosen@yahoo.com> - 2024-05-04 22:04 +0300
                Re: Threads across programming languages David Brown <david.brown@hesbynett.no> - 2024-05-05 14:56 +0200
                Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-04 17:36 +0200
                Re: Threads across programming languages Michael S <already5chosen@yahoo.com> - 2024-05-04 22:11 +0300
                Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-04 12:59 -0700
                Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-01 22:20 -0700
                Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-01 22:22 -0700
              Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-01 11:55 -0700
        Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-01 11:55 -0700
    Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-01 06:53 +0200
      Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-01 07:09 +0000
        Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-01 10:11 +0200
          Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-01 08:53 +0000
            Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-01 11:00 +0200
              Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-01 20:31 +0000
                Re: Threads across programming languages scott@slp53.sl.home (Scott Lurndal) - 2024-05-01 21:00 +0000
                Re: Threads across programming languages Michael S <already5chosen@yahoo.com> - 2024-05-02 00:05 +0300
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-01 23:05 +0000
                Re: Threads across programming languages Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-02 05:46 +0200
                Re: Threads across programming languages "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-05-02 13:33 -0700
                Re: Threads across programming languages Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-05-03 22:22 +0000
  Re: Threads across programming languages scott@slp53.sl.home (Scott Lurndal) - 2024-04-30 16:48 +0000

csiph-web