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Groups > comp.lang.c++ > #70821

Re: What is the data structure of a NULL?

Newsgroups comp.lang.c++
Date 2019-12-30 06:03 -0800
References (4 earlier) <slrnr0gbbl.tg9.nedlatham@woden.valhalla.oz> <87k16fr9za.fsf@nosuchdomain.example.com> <slrnr0h0v1.to9.nedlatham@woden.valhalla.oz> <qubjcd$glg$1@dont-email.me> <slrnr0isv8.uul.nedlatham@woden.valhalla.oz>
Message-ID <91dfd68d-0094-4edf-bef1-31bf55b24aa1@googlegroups.com> (permalink)
Subject Re: What is the data structure of a NULL?
From James Kuyper <jameskuyper@alumni.caltech.edu>

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Ned Latham wrote:
> James Kuyper wrote:
...
> > Can you give an example of code involving a null pointer that you could
> > not have used if you had not known how null pointers are represented? I
> > write code that deals correctly with null pointers all the time, and to
> > the best of my knowledge, not a single line of code I've ever written
> > would need a re-write if ported to a system which uses a different
> > representation for null pointers.

> http://www.users.on.net/~nedlatham/Software/mclib/Documents/sourcecode.html

> Check AVLC and ListC, also read
> http://www.users.on.net/~nedlatham/Software/mclib/Documents/mclists.html

That is not the kind of response I was asking for. Let me be more explicit:
I'm looking for a single C++ construct, from a single line of code, that
you were only able to use because of what you know about how null pointers
are represented on the target implementation. That is, inherently, a
construct that would not produce the desired result if the code were ported
to an implementation that uses a different way to represent null pointers.
It's fine if you need to provide additional lines of code, or even system
documentation, to provide the proper context for that construct. However,
I need you to actually identify the particular construct you're referring
to. Can you give me the exact location in that body of code of at least
one such construct? Better yet, could you quote that line of code?

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Thread

What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-27 13:24 -0800
  Re: What is the data structure of a NULL? Ian Collins <ian-news@hotmail.com> - 2019-12-28 10:36 +1300
    Re: What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-27 13:55 -0800
      Re: What is the data structure of a NULL? Bo Persson <bo@bo-persson.se> - 2019-12-28 11:28 +0100
    Re: What is the data structure of a NULL? James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-12-27 20:50 -0500
      Re: What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-28 17:14 -0800
      Re: What is the data structure of a NULL? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-01-10 20:56 -0800
  Re: What is the data structure of a NULL? "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-12-27 22:42 +0100
    Re: What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-27 13:55 -0800
      Re: What is the data structure of a NULL? "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-12-27 23:10 +0100
      Re: What is the data structure of a NULL? Öö Tiib <ootiib@hot.ee> - 2019-12-27 14:15 -0800
        Re: What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-27 14:24 -0800
          Re: What is the data structure of a NULL? Öö Tiib <ootiib@hot.ee> - 2019-12-27 14:41 -0800
          Re: What is the data structure of a NULL? Manfred <noname@add.invalid> - 2019-12-28 20:11 +0100
            Re: What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-28 17:16 -0800
              Re: What is the data structure of a NULL? Manfred <noname@invalid.add> - 2019-12-29 17:52 +0100
                Re: What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-29 12:21 -0800
      Re: What is the data structure of a NULL? Bart <bc@freeuk.com> - 2019-12-28 01:46 +0000
        Re: What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-28 17:17 -0800
          Re: What is the data structure of a NULL? Bart <bc@freeuk.com> - 2019-12-29 01:42 +0000
            Re: What is the data structure of a NULL? T <T@invalid.invalid> - 2019-12-28 18:39 -0800
  Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-28 02:14 -0800
    Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-28 08:33 -0600
      Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-28 13:22 -0800
        Re: What is the data structure of a NULL? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2019-12-28 16:02 -0800
          Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-28 22:37 -0600
        Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-28 22:37 -0600
          Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-28 21:12 -0800
            Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-29 04:45 -0600
              Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-29 13:31 -0800
                Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-29 21:34 -0600
                Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-29 22:48 -0800
              Re: What is the data structure of a NULL? James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-12-29 20:20 -0500
                Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-29 21:50 -0600
                Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-29 22:46 -0800
                Re: What is the data structure of a NULL? David Brown <david.brown@hesbynett.no> - 2019-12-30 10:25 +0100
                Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-30 05:20 -0600
                Re: What is the data structure of a NULL? David Brown <david.brown@hesbynett.no> - 2019-12-30 17:24 +0100
                Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-30 17:22 -0600
                Re: What is the data structure of a NULL? David Brown <david.brown@hesbynett.no> - 2019-12-31 13:57 +0100
                Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-31 07:33 -0600
                Re: What is the data structure of a NULL? David Brown <david.brown@hesbynett.no> - 2019-12-31 15:45 +0100
                Re: What is the data structure of a NULL? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-12-30 18:16 +0000
                Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-30 10:45 -0800
                Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-30 17:29 -0600
                Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-30 21:48 -0800
                Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-30 04:19 -0600
                Re: What is the data structure of a NULL? David Brown <david.brown@hesbynett.no> - 2019-12-30 17:27 +0100
                Re: What is the data structure of a NULL? Öö Tiib <ootiib@hot.ee> - 2019-12-30 03:25 -0800
                Re: What is the data structure of a NULL? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-12-31 21:54 +0000
                Re: What is the data structure of a NULL? James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-12-30 06:03 -0800
                Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-30 17:01 -0600
                Re: What is the data structure of a NULL? James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-12-30 21:42 -0500
                Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-31 06:03 -0600
                Re: What is the data structure of a NULL? Öö Tiib <ootiib@hot.ee> - 2019-12-31 06:17 -0800
                Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-31 10:46 -0600
                Re: What is the data structure of a NULL? Melzzzzz <Melzzzzz@zzzzz.com> - 2019-12-31 16:57 +0000
                Re: What is the data structure of a NULL? David Brown <david.brown@hesbynett.no> - 2019-12-31 18:15 +0100
                Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-31 11:20 -0800
                Re: What is the data structure of a NULL? David Brown <david.brown@hesbynett.no> - 2020-01-01 17:01 +0100
                Re: What is the data structure of a NULL? Ned Latham <nedlatham@woden.valhalla.oz> - 2019-12-31 11:21 -0600
                Re: What is the data structure of a NULL? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-12-31 21:37 +0000
                Re: What is the data structure of a NULL? James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-12-31 15:21 -0800
                Re: What is the data structure of a NULL? Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2019-12-31 17:26 +0000
                Re: What is the data structure of a NULL? James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-12-31 23:30 -0500
                Re: What is the data structure of a NULL? Manfred <noname@add.invalid> - 2020-01-01 18:10 +0100
                Re: What is the data structure of a NULL? James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-01-01 12:21 -0500
                Re: What is the data structure of a NULL? Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2019-12-31 15:20 +0000
                Re: What is the data structure of a NULL? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2019-12-31 11:11 -0800
                Re: What is the data structure of a NULL? Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2019-12-31 19:47 +0000
                Re: What is the data structure of a NULL? James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-12-31 10:27 -0800

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