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Groups > comp.lang.c > #124070

Re: NULL as the empty string

From Keith Thompson <kst-u@mib.org>
Newsgroups comp.lang.c
Subject Re: NULL as the empty string
Date 2017-12-09 11:53 -0800
Organization None to speak of
Message-ID <ln374jsmof.fsf@kst-u.example.com> (permalink)
References (8 earlier) <p0f7ki$6t5$1@dont-email.me> <lnr2s4sr4c.fsf@kst-u.example.com> <p0fap8$oin$1@dont-email.me> <ln7etwsmd7.fsf@kst-u.example.com> <p0fuek$65u$1@dont-email.me>

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jacobnavia <jacob@jacob.remcomp.fr> writes:
> Le 09/12/2017 à 02:47, Keith Thompson a écrit :
>> Would it be more convenient to treat a floating-point NaN as equivalent
>> to 0.0?  
[...]
> What is your point here? We are talking about strings, not floating 
> point numbers. I just made a comparison between a representation of 
> something that is a special value (NAN or inf) and the representation of 
> the empty string, that could be the NULL pointer.

My point is that in floating-point we have a clear and useful
distinction between a "null" value, 0.0, and a representation that
isn't a numeric value, NaN.

For char*, we have a clear distinction between a pointer to an
empty string and a pointer that doesn't point to a string at all.
They're logically quite distinct, and in my opinion it's a very
useful distinction.

I concede that it's not a very compelling point.  Still, I don't
think treating a null pointer as if it were a pointer to an empty
string is a good idea.  It's not a *horrible* idea, and if it were
added to a future standard I'd accept it with a little grumbling.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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Thread

NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-11-21 23:52 +0100
  Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-11-21 15:16 -0800
    Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-11-22 00:38 +0100
      Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-11-21 16:02 -0800
        Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-11-22 01:13 +0100
          Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-11-21 16:52 -0800
      Re: NULL as the empty string Robert Wessel <robertwessel2@yahoo.com> - 2017-11-21 18:09 -0600
      Re: NULL as the empty string Siri Cruise <chine.bleu@yahoo.com> - 2017-11-21 16:34 -0800
      Re: NULL as the empty string David Brown <david.brown@hesbynett.no> - 2017-11-22 12:12 +0100
    Re: NULL as the empty string supercat@casperkitty.com - 2017-11-21 15:57 -0800
      Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-11-22 01:06 +0100
        Re: NULL as the empty string supercat@casperkitty.com - 2017-11-22 15:42 -0800
          Re: NULL as the empty string Melzzzzz <Melzzzzz@zzzzz.com> - 2017-11-22 23:49 +0000
            Re: NULL as the empty string supercat@casperkitty.com - 2017-11-22 15:56 -0800
              Re: NULL as the empty string Melzzzzz <Melzzzzz@zzzzz.com> - 2017-11-23 00:06 +0000
                Re: NULL as the empty string supercat@casperkitty.com - 2017-11-23 17:31 -0800
                Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-11-24 09:42 +0100
                Re: NULL as the empty string supercat@casperkitty.com - 2017-11-24 13:47 -0800
    Re: NULL as the empty string Jorgen Grahn <grahn+nntp@snipabacken.se> - 2017-11-22 06:46 +0000
    Re: NULL as the empty string John Bode <jfbode1029@gmail.com> - 2017-12-08 10:27 -0800
      Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-12-08 11:11 -0800
        Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-12-08 21:39 +0100
          Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-12-08 13:03 -0800
            Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-12-08 22:50 +0100
              Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-12-08 15:19 -0800
                Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-12-09 00:35 +0100
                Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-12-08 16:05 -0800
                Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-12-09 01:22 +0100
                Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-12-08 17:39 -0800
                Re: NULL as the empty string John Bode <jfbode1029@gmail.com> - 2017-12-11 12:22 -0800
                Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-12-09 01:29 +0100
                Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-12-08 17:47 -0800
                Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-12-09 07:05 +0100
                Re: NULL as the empty string David Brown <david.brown@hesbynett.no> - 2017-12-09 18:37 +0100
                Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-12-09 11:53 -0800
                Re: NULL as the empty string supercat@casperkitty.com - 2017-12-12 10:49 -0800
                Re: NULL as the empty string Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-12-12 13:39 -0800
                Re: NULL as the empty string supercat@casperkitty.com - 2017-12-12 16:05 -0800
                Re: NULL as the empty string Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-12-13 03:43 -0800
                Re: NULL as the empty string supercat@casperkitty.com - 2017-12-13 08:45 -0800
                Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-12-13 09:12 -0800
                Re: NULL as the empty string Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-12-13 13:27 -0800
                Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-12-13 14:02 -0800
                Re: NULL as the empty string asetofsymbols@gmail.com - 2017-12-13 14:58 -0800
                Re: NULL as the empty string asetofsymbols@gmail.com - 2017-12-13 15:11 -0800
                Re: NULL as the empty string Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-12-14 03:49 -0800
                Re: NULL as the empty string mark.bluemel@gmail.com - 2017-12-14 04:05 -0800
                Re: NULL as the empty string David Brown <david.brown@hesbynett.no> - 2017-12-14 13:09 +0100
                Re: NULL as the empty string Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-12-14 05:02 -0800
                Re: NULL as the empty string David Brown <david.brown@hesbynett.no> - 2017-12-14 14:54 +0100
                Re: NULL as the empty string supercat@casperkitty.com - 2017-12-14 07:38 -0800
                Re: NULL as the empty string Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-12-14 09:50 -0800
                Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-12-14 09:20 -0800
                Re: NULL as the empty string supercat@casperkitty.com - 2017-12-14 09:53 -0800
                Re: NULL as the empty string Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-12-14 12:57 -0800
                Re: NULL as the empty string herrmannsfeldt@gmail.com - 2017-12-14 17:22 -0800
                Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-12-14 17:26 -0800
      Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-12-08 21:23 +0100
        Re: NULL as the empty string Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-12-08 13:41 -0800
          Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-12-08 22:54 +0100
  Re: NULL as the empty string supercat@casperkitty.com - 2017-11-21 15:17 -0800
    Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-11-22 00:26 +0100
      Re: NULL as the empty string supercat@casperkitty.com - 2017-11-21 16:03 -0800
  Re: NULL as the empty string "Pascal J. Bourguignon" <pjb@informatimago.com> - 2017-11-22 00:27 +0100
    Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-11-22 00:42 +0100
      Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-11-21 16:05 -0800
        Re: NULL as the empty string herrmannsfeldt@gmail.com - 2017-12-06 22:33 -0800
          Re: NULL as the empty string supercat@casperkitty.com - 2017-12-07 12:04 -0800
            Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-12-07 23:20 +0100
              Re: NULL as the empty string supercat@casperkitty.com - 2017-12-07 15:04 -0800
  Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-11-21 15:28 -0800
  Re: NULL as the empty string Thiago Adams <thiago.adams@gmail.com> - 2017-11-21 16:04 -0800
  Re: NULL as the empty string Siri Cruise <chine.bleu@yahoo.com> - 2017-11-21 16:25 -0800
    Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-11-22 01:34 +0100
  Re: NULL as the empty string bartc <bc@freeuk.com> - 2017-11-22 00:36 +0000
  Re: NULL as the empty string Öö Tiib <ootiib@hot.ee> - 2017-11-21 23:07 -0800
  NULL as the empty string asetofsymbols@gmail.com - 2017-11-23 22:23 -0800
  Re: NULL as the empty string Geoff <geoff@invalid.invalid> - 2017-12-09 09:05 -0800
    Re: NULL as the empty string Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2017-12-09 12:40 -0500
  Re: NULL as the empty string gordonb.yj0bc@burditt.org (Gordon Burditt) - 2017-12-09 13:50 -0600
  Re: NULL as the empty string Ian Collins <ian-news@hotmail.com> - 2017-12-10 08:59 +1300
    Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-12-09 12:22 -0800
      Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-12-11 01:42 +0100
        Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-12-10 19:20 -0800
          Re: NULL as the empty string jacobnavia <jacob@jacob.remcomp.fr> - 2017-12-11 18:56 +0100
            Re: NULL as the empty string Keith Thompson <kst-u@mib.org> - 2017-12-11 11:19 -0800
        Re: NULL as the empty string supercat@casperkitty.com - 2017-12-15 09:29 -0800
          Re: NULL as the empty string Thiago Adams <thiago.adams@gmail.com> - 2018-01-05 08:28 -0800
            Re: NULL as the empty string supercat@casperkitty.com - 2018-01-05 09:37 -0800
              Re: NULL as the empty string Thiago Adams <thiago.adams@gmail.com> - 2018-01-05 17:08 -0800
    Re: NULL as the empty string supercat@casperkitty.com - 2017-12-15 09:18 -0800

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