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Re: Pointers as error values

From "Morten W. Petersen" <morphex@gmail.com>
Newsgroups comp.lang.c
Subject Re: Pointers as error values
Date 2015-10-30 11:05 +0100
Organization Aioe.org NNTP Server
Message-ID <n0vfdg$eks$1@speranza.aioe.org> (permalink)
References (2 earlier) <n0781l$lg2$1@speranza.aioe.org> <slrnn2fjpm.dkf.usenet@xargs-spam.com> <n08kk2$a6d$1@dont-email.me> <n0tfor$ek6$1@speranza.aioe.org> <46t53b5nqbf6dr81i66cemgup70kclk7qf@4ax.com>

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On 30.10.2015 05:48, Robert Wessel wrote:
[...]
> IOW, you can't do:
>
>    char errors[7];
>    ...
>    ptr = somefunc();
>    if (ptr >= (errors+0)  && ptr <= (errors+6))
>      handle_errror_1_6();
>
> To see if it matches any of those.  If you don't know that the
> pointers are to the same object, (in)equality is the only thing you
> can portably test.
>
> Basically, don't do that.

OK.  And what does portable mean here?  What are the examples of
allocating a small array where each member of that array do not have a
sequential ascending or descending address?

-Morten

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Thread

Pointers as error values "Morten W. Petersen" <morphex@gmail.com> - 2015-10-19 00:53 -0700
  Re: Pointers as error values gazelle@shell.xmission.com (Kenny McCormack) - 2015-10-19 08:26 +0000
    Re: Pointers as error values "Morten W. Petersen" <morphex@gmail.com> - 2015-10-19 02:27 -0700
    Re: Pointers as error values Richard Damon <Richard@Damon-Family.org> - 2015-10-19 23:38 -0400
  Re: Pointers as error values jacobnavia <jacob@jacob.remcomp.fr> - 2015-10-19 10:34 +0200
    Re: Pointers as error values "Morten W. Petersen" <morphex@gmail.com> - 2015-10-19 02:29 -0700
    Re: Pointers as error values mark.bluemel@gmail.com - 2015-10-19 05:53 -0700
  Re: Pointers as error values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-19 10:00 +0000
  Re: Pointers as error values Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-10-19 14:00 +0000
  Re: Pointers as error values gwowen <gwowen@gmail.com> - 2015-10-19 08:02 -0700
    Re: Pointers as error values James Kuyper <jameskuyper@verizon.net> - 2015-10-19 11:53 -0400
  Re: Pointers as error values Ken Brody <kenbrody@spamcop.net> - 2015-10-19 11:25 -0400
  Re: Pointers as error values supercat@casperkitty.com - 2015-10-19 08:41 -0700
  Re: Pointers as error values Keith Thompson <kst-u@mib.org> - 2015-10-19 08:59 -0700
    Re: Pointers as error values "Morten W. Petersen" <morphex@gmail.com> - 2015-10-21 07:32 +0200
      Re: Pointers as error values Ian Collins <ian-news@hotmail.com> - 2015-10-21 19:17 +1300
        Re: Pointers as error values "Morten W. Petersen" <morphex@gmail.com> - 2015-10-21 08:31 +0200
      Re: Pointers as error values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-21 12:46 +0100
      Re: Pointers as error values Robert Wessel <robertwessel2@yahoo.com> - 2015-10-21 09:35 -0500
        Re: Pointers as error values Ken Brody <kenbrody@spamcop.net> - 2015-10-21 15:24 -0400
          Re: Pointers as error values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-22 05:44 +0000
      Re: Pointers as error values Keith Thompson <kst-u@mib.org> - 2015-10-21 10:41 -0700
        Re: Pointers as error values supercat@casperkitty.com - 2015-10-21 11:28 -0700
      Re: Pointers as error values John Temples <usenet@xargs-spam.com> - 2015-10-21 17:45 +0000
        Re: Pointers as error values James Kuyper <jameskuyper@verizon.net> - 2015-10-21 14:15 -0400
          Re: Pointers as error values "Morten W. Petersen" <morphex@gmail.com> - 2015-10-29 16:59 +0100
            Re: Pointers as error values supercat@casperkitty.com - 2015-10-29 12:35 -0700
              Re: Pointers as error values raltbos@xs4all.nl (Richard Bos) - 2015-10-29 21:45 +0000
                Re: Pointers as error values "Morten W. Petersen" <morphex@gmail.com> - 2015-10-30 06:09 +0100
                Re: Pointers as error values Rosario19 <Ros@invalid.invalid> - 2015-10-30 08:59 +0100
                Re: Pointers as error values Rosario19 <Ros@invalid.invalid> - 2015-10-30 09:07 +0100
                Re: Pointers as error values Rosario19 <Ros@invalid.invalid> - 2015-10-30 09:38 +0100
                Re: Pointers as error values Rosario19 <Ros@invalid.invalid> - 2015-10-30 09:40 +0100
                Re: Pointers as error values Robert Wessel <robertwessel2@yahoo.com> - 2015-10-30 04:56 -0500
                Re: Pointers as error values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-30 11:00 +0000
            Re: Pointers as error values Robert Wessel <robertwessel2@yahoo.com> - 2015-10-29 23:48 -0500
              Re: Pointers as error values "Morten W. Petersen" <morphex@gmail.com> - 2015-10-30 11:05 +0100
                Re: Pointers as error values Richard Damon <Richard@Damon-Family.org> - 2015-10-30 07:45 -0400
                Re: Pointers as error values Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-30 05:04 -0700
                Re: Pointers as error values "Morten W. Petersen" <morphex@gmail.com> - 2015-10-30 16:09 +0100
                Re: Pointers as error values Keith Thompson <kst-u@mib.org> - 2015-10-30 11:16 -0700
                Re: Pointers as error values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-30 20:58 +0000
                Re: Pointers as error values Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-30 17:12 -0400
                Re: Pointers as error values supercat@casperkitty.com - 2015-10-30 14:54 -0700
                Re: Pointers as error values Robert Wessel <robertwessel2@yahoo.com> - 2015-10-30 18:48 -0500
                Re: Pointers as error values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-11-01 04:00 +0000
                Re: Pointers as error values Robert Wessel <robertwessel2@yahoo.com> - 2015-11-01 01:24 -0500
                Re: Pointers as error values "Morten W. Petersen" <morphex@gmail.com> - 2015-10-31 20:35 +0100
                Re: Pointers as error values supercat@casperkitty.com - 2015-10-31 13:33 -0700
                Re: Pointers as error values Richard Damon <Richard@Damon-Family.org> - 2015-10-30 22:19 -0400
                Re: Pointers as error values supercat@casperkitty.com - 2015-10-30 08:22 -0700
                Re: Pointers as error values Geoff <geoff@invalid.invalid> - 2015-10-30 13:11 -0700
                Re: Pointers as error values Geoff <geoff@invalid.invalid> - 2015-10-30 13:23 -0700
      Re: Pointers as error values Geoff <geoff@invalid.invalid> - 2015-10-21 11:13 -0700
        Re: Pointers as error values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-21 20:31 +0100
          Re: Pointers as error values Geoff <geoff@invalid.invalid> - 2015-10-22 07:13 -0700
        Re: Pointers as error values "Morten W. Petersen" <morphex@gmail.com> - 2015-10-26 07:16 +0100
          Re: Pointers as error values Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-10-26 09:37 +0000
      Re: Pointers as error values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-22 05:38 +0000
        Re: Pointers as error values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-22 13:51 +0100
        Re: Pointers as error values Keith Thompson <kst-u@mib.org> - 2015-10-22 08:29 -0700
          Re: Pointers as error values supercat@casperkitty.com - 2015-10-22 09:21 -0700
            Re: Pointers as error values Keith Thompson <kst-u@mib.org> - 2015-10-22 10:52 -0700
              Re: Pointers as error values "Morten W. Petersen" <morphex@gmail.com> - 2015-10-26 07:20 +0100
                Re: Pointers as error values Keith Thompson <kst-u@mib.org> - 2015-10-26 08:09 -0700
                Re: Pointers as error values supercat@casperkitty.com - 2015-10-26 08:40 -0700
                Re: Pointers as error values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-26 20:02 +0000
                Re: Pointers as error values supercat@casperkitty.com - 2015-10-26 13:56 -0700
          Re: Pointers as error values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-22 21:58 +0000
            Re: Pointers as error values James Kuyper <jameskuyper@verizon.net> - 2015-10-22 19:12 -0400
            Re: Pointers as error values asetofsymbols@gmail.com - 2015-10-22 18:36 -0700
              Re: Pointers as error values asetofsymbols@gmail.com - 2015-10-29 12:47 -0700
  Re: Pointers as error values Lőrinczy Zsigmond <nospam@for.me> - 2015-10-20 17:06 +0200
    Re: Pointers as error values Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-20 19:45 +0100
      Re: Pointers as error values supercat@casperkitty.com - 2015-10-20 14:19 -0700
        Re: Pointers as error values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-21 05:28 +0000
          Re: Pointers as error values supercat@casperkitty.com - 2015-10-21 05:48 -0700
            Re: Pointers as error values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-22 05:52 +0000
          Re: Pointers as error values Ken Brody <kenbrody@spamcop.net> - 2015-10-21 15:19 -0400
            Re: Pointers as error values glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-22 06:06 +0000

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