Re: question about nullptr

From	Keith Thompson <Keith.S.Thompson+u@gmail.com>
Newsgroups	comp.lang.c
Subject	Re: question about nullptr
Date	2024-07-10 14:15 -0700
Organization	None to speak of
Message-ID	<87h6cxuexa.fsf@nosuchdomain.example.com> (permalink)
References	(7 earlier) <9bCiO.7108$sXW9.3805@fx41.iad> <877cdwu9s1.fsf@nosuchdomain.example.com> <v6if96$18hur$1@dont-email.me> <87y16bw1hf.fsf@nosuchdomain.example.com> <86r0c18gbl.fsf@linuxsc.com>

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Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
> Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:
>> Hmm.  I like the idea of a type-agnostic way to express a "zero"
>> value, [but] C's use of 0 for all scalar types strikes me more as
>> an historical accident than a design feature.
>
> I don't think it was an accident at all.  It was chosen to be
> consistent with how if(), while(), !, ?:, and so forth, all act.
> There is a very consistent design philosophy there.  Sometimes
> people who come from a strong Pascal background don't like it,
> but personally I find the C model easier and more convenient to
> work with than the Pascal model.

In early C, int was in a very real sense the default type.  In B,
types weren't even explicit, and IIRC variables were effectively "of
type int", or more precisely a 16-bit PDP-11 word.  (I'm glossing
over some details of B, many of which I don't know).  In that
context 0 made sense as a general-purpose "zero" value.

Modern C has moved away from making int some kind of default
(though it hasn't entirely done so).

What I dislike is the fact that 0 is *both* of the specific type
int *and* is commonly used as a general-purpose scalar 0.

I accept it because it's the way the language is defined, but
IMHO it's perhaps not an historical accident (you're right, it was
deliberate), but more of an historical relic.

Which is why I use 0 for integers, '\0' for characters, 0.0 for
floating-point, and NULL (or nullptr if it's available) for pointers.
If there were some general-purpose zero token that *isn't* of a
specific type (I mentioned "{}" upthread), I'd probably use that.
But it's not enough of a problem that I'd necessarily advocate a
language change.  And if someone else consistently uses 0 in pointer
context, I'll waste about half a second being annoyed and then move on.

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */

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question about nullptr Thiago Adams <thiago.adams@gmail.com> - 2024-07-06 08:49 -0300
  Re: question about nullptr Bonita Montero <Bonita.Montero@gmail.com> - 2024-07-06 14:13 +0200
  Re: question about nullptr John McCue <jmccue@neutron.jmcunx.com> - 2024-07-06 12:33 +0000
  Re: question about nullptr Kaz Kylheku <643-408-1753@kylheku.com> - 2024-07-06 12:54 +0000
    Re: question about nullptr Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-07-06 15:07 +0200
      Re: question about nullptr scott@slp53.sl.home (Scott Lurndal) - 2024-07-06 14:04 +0000
        Re: question about nullptr Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-07-06 16:42 +0200
          Re: question about nullptr Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-07-06 16:45 +0200
        Re: question about nullptr Andrey Tarasevich <andreytarasevich@hotmail.com> - 2024-07-06 10:50 -0700
          Re: question about nullptr scott@slp53.sl.home (Scott Lurndal) - 2024-07-06 23:04 +0000
            Re: question about nullptr Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-07-06 20:06 -0700
        Re: question about nullptr bart <bc@freeuk.com> - 2024-07-06 19:20 +0100
          Re: question about nullptr scott@slp53.sl.home (Scott Lurndal) - 2024-07-06 23:09 +0000
          Re: question about nullptr Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-07-06 16:31 -0700
        Re: question about nullptr "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-07-06 13:23 -0700
          Re: question about nullptr "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-07-06 13:28 -0700
            Re: question about nullptr Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-07-07 08:01 +0000
              Re: question about nullptr "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-07-08 22:08 -0700
          Re: question about nullptr Richard Damon <richard@damon-family.org> - 2024-07-06 17:04 -0400
            Re: question about nullptr scott@slp53.sl.home (Scott Lurndal) - 2024-07-06 23:10 +0000
          Re: question about nullptr scott@slp53.sl.home (Scott Lurndal) - 2024-07-06 23:03 +0000
          Re: question about nullptr James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-07-06 21:44 -0400
            Re: question about nullptr Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-07-06 19:29 -0700
              Re: question about nullptr "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-07-07 12:53 -0700
          Re: question about nullptr Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-07-07 08:03 +0000
        Re: question about nullptr Ben Bacarisse <ben@bsb.me.uk> - 2024-07-06 23:14 +0100
          Re: question about nullptr scott@slp53.sl.home (Scott Lurndal) - 2024-07-06 23:13 +0000
            Re: question about nullptr Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-07-06 20:10 -0700
            Re: question about nullptr Kaz Kylheku <643-408-1753@kylheku.com> - 2024-07-07 08:46 +0000
            Re: question about nullptr Ben Bacarisse <ben@bsb.me.uk> - 2024-07-07 19:59 +0100
              Re: question about nullptr scott@slp53.sl.home (Scott Lurndal) - 2024-07-07 19:40 +0000
                Re: question about nullptr Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-07-07 15:17 -0700
                Re: question about nullptr Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-07-08 20:11 +0200
                Re: question about nullptr Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-07-08 13:32 -0700
                Re: question about nullptr Michael S <already5chosen@yahoo.com> - 2024-07-08 22:28 +0300
                Re: question about nullptr "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-07-08 15:23 -0700
                Re: question about nullptr Michael S <already5chosen@yahoo.com> - 2024-07-09 10:48 +0300
                Re: question about nullptr Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-07-09 04:32 -0700
                Re: question about nullptr Thiago Adams <thiago.adams@gmail.com> - 2024-07-09 09:10 -0300
                Re: question about nullptr Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-07-09 07:52 -0700
                Re: question about nullptr Thiago Adams <thiago.adams@gmail.com> - 2024-07-09 13:16 -0300
                Re: question about nullptr Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-07-09 14:22 -0700
                Re: question about nullptr Kaz Kylheku <643-408-1753@kylheku.com> - 2024-07-09 22:25 +0000
                Re: question about nullptr Thiago Adams <thiago.adams@gmail.com> - 2024-07-10 08:50 -0300
                Re: question about nullptr Michael S <already5chosen@yahoo.com> - 2024-07-09 15:50 +0300
                Re: question about nullptr Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-07-09 07:50 -0700
                Re: question about nullptr David Brown <david.brown@hesbynett.no> - 2024-07-09 18:19 +0200
                Re: question about nullptr Kaz Kylheku <643-408-1753@kylheku.com> - 2024-07-09 02:49 +0000
                Re: question about nullptr Michael S <already5chosen@yahoo.com> - 2024-07-09 11:00 +0300
                Re: question about nullptr Kaz Kylheku <643-408-1753@kylheku.com> - 2024-07-09 08:21 +0000
                Re: question about nullptr Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-07-09 03:57 -0700
                Re: question about nullptr Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-07-08 20:17 -0700
                Re: question about nullptr Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-07-08 21:01 -0700
                Re: question about nullptr "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-07-08 22:06 -0700
                Re: question about nullptr Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-07-10 07:51 -0700
                Re: question about nullptr Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-07-10 14:23 -0700
                Re: question about nullptr James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-07-10 18:50 -0400
                Re: question about nullptr scott@slp53.sl.home (Scott Lurndal) - 2024-07-08 14:09 +0000
                Re: question about nullptr Andrey Tarasevich <andreytarasevich@hotmail.com> - 2024-07-08 21:45 -0700
                Re: question about nullptr Andrey Tarasevich <andreytarasevich@hotmail.com> - 2024-07-08 21:49 -0700
                Re: question about nullptr Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-07-11 02:42 +0000
                Re: question about nullptr Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-07-08 22:58 -0700
                Re: question about nullptr Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-07-10 07:36 -0700
                Re: question about nullptr Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-07-10 14:15 -0700
                Re: question about nullptr Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-08-11 20:52 -0700
                Re: question about nullptr Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-07-08 20:07 +0200
                Re: question about nullptr Ben Bacarisse <ben@bsb.me.uk> - 2024-07-08 23:55 +0100
                Re: question about nullptr Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-07-10 17:28 +0200
                Re: question about nullptr Ben Bacarisse <ben@bsb.me.uk> - 2024-07-11 00:25 +0100
                Re: question about nullptr Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-07-12 14:08 +0200
                Re: question about nullptr Ben Bacarisse <ben@bsb.me.uk> - 2024-07-13 00:59 +0100
                Re: question about nullptr Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-07-13 04:01 +0200
                Re: question about nullptr Ben Bacarisse <ben@bsb.me.uk> - 2024-07-15 00:00 +0100
                Re: question about nullptr Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-07-13 04:18 +0200
                Re: question about nullptr Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-07-17 09:26 -0700
                Re: question about nullptr Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-07-08 12:29 +0200
                Re: question about nullptr Ben Bacarisse <ben@bsb.me.uk> - 2024-07-08 17:23 +0100
                Re: question about nullptr James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-07-08 11:03 -0400
                Re: question about nullptr Kaz Kylheku <643-408-1753@kylheku.com> - 2024-07-09 02:45 +0000
                Re: question about nullptr Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-07-08 11:08 +0200
                Re: question about nullptr Ben Bacarisse <ben@bsb.me.uk> - 2024-07-08 11:18 +0100
                Re: question about nullptr Kaz Kylheku <643-408-1753@kylheku.com> - 2024-07-09 02:32 +0000
                Re: question about nullptr "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-07-08 22:02 -0700
                Re: question about nullptr Ben Bacarisse <ben@bsb.me.uk> - 2024-07-09 10:21 +0100
                Re: question about nullptr "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-07-10 17:32 -0700
                Re: question about nullptr Ben Bacarisse <ben@bsb.me.uk> - 2024-07-11 02:12 +0100
                Re: question about nullptr "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-07-10 18:41 -0700
                Re: question about nullptr Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-07-11 02:38 +0000
                Re: question about nullptr Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-07-12 14:11 +0200
                Re: question about nullptr Richard Damon <richard@damon-family.org> - 2024-07-08 07:18 -0400
                Re: question about nullptr Kaz Kylheku <643-408-1753@kylheku.com> - 2024-07-08 07:19 +0000
                Re: question about nullptr Ben Bacarisse <ben@bsb.me.uk> - 2024-07-08 00:42 +0100
          Re: question about nullptr Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-07-06 20:36 -0700
      Re: question about nullptr Kaz Kylheku <643-408-1753@kylheku.com> - 2024-07-06 22:11 +0000
    Re: question about nullptr bart <bc@freeuk.com> - 2024-07-06 14:51 +0100
      Re: question about nullptr Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-07-07 04:55 +0000
        Re: question about nullptr Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-07-07 00:04 -0700
        Re: question about nullptr bart <bc@freeuk.com> - 2024-07-07 18:40 +0100
    Re: question about nullptr Richard Harnden <richard.nospam@gmail.invalid> - 2024-07-12 14:19 +0100
      Re: question about nullptr Kaz Kylheku <643-408-1753@kylheku.com> - 2024-07-12 21:52 +0000
        Re: question about nullptr scott@slp53.sl.home (Scott Lurndal) - 2024-07-12 22:27 +0000
          Re: question about nullptr Kaz Kylheku <643-408-1753@kylheku.com> - 2024-07-12 23:28 +0000
            Re: question about nullptr scott@slp53.sl.home (Scott Lurndal) - 2024-07-13 00:10 +0000
              Re: question about nullptr James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-07-12 20:28 -0400
              Re: question about nullptr Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-07-12 17:30 -0700
      Re: question about nullptr Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-07-13 17:21 -0700
      Re: question about nullptr Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-07-15 22:51 +0000
        Re: question about nullptr Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-07-15 16:32 -0700
        Re: question about nullptr James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-07-15 19:49 -0400
          Re: question about nullptr Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-07-15 18:22 -0700
  Re: question about nullptr Richard Damon <richard@damon-family.org> - 2024-07-06 10:39 -0400
    Re: question about nullptr David Brown <david.brown@hesbynett.no> - 2024-07-06 18:57 +0200
      Re: question about nullptr Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-07-07 08:00 +0000
        Re: question about nullptr David Brown <david.brown@hesbynett.no> - 2024-07-07 12:07 +0200
      Re: question about nullptr Thiago Adams <thiago.adams@gmail.com> - 2024-07-07 08:40 -0300
      Re: question about nullptr Richard Harnden <richard.nospam@gmail.invalid> - 2024-07-09 06:42 +0100
        Re: question about nullptr "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-07-08 23:17 -0700
          Re: question about nullptr Richard Harnden <richard.nospam@gmail.invalid> - 2024-07-09 08:02 +0100
            Re: question about nullptr "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-07-09 00:12 -0700
              Re: question about nullptr Ben Bacarisse <ben@bsb.me.uk> - 2024-07-09 11:14 +0100
                Re: question about nullptr "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-07-09 13:24 -0700
                Re: question about nullptr "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-07-09 13:28 -0700
                Re: question about nullptr Ben Bacarisse <ben@bsb.me.uk> - 2024-07-10 14:27 +0100
                Re: question about nullptr James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-07-10 11:09 -0400

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