Re: Issues with setting variables to true or false: how does the compiler understands it

From	Keith Thompson <kst-u@mib.org>
Newsgroups	comp.lang.c
Subject	Re: Issues with setting variables to true or false: how does the compiler understands it
Date	2015-10-27 13:41 -0700
Organization	None to speak of
Message-ID	<lnk2q8cae8.fsf@kst-u.example.com> (permalink)
References	(11 earlier) <3f17ab8c-150b-47a2-ab76-03dc2a0b5091@googlegroups.com> <n0ogv0$44b$1@dont-email.me> <48b8f74a-d34b-4c8a-82f7-40522ed2cf16@googlegroups.com> <n0ojfi$dvu$1@dont-email.me> <405bd34c-e92d-43e9-b0cc-ee60744267b4@googlegroups.com>

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supercat@casperkitty.com writes:
> On Tuesday, October 27, 2015 at 2:34:24 PM UTC-5, Bart wrote:
>> Then it would be a binary file IMO. You have to draw the line somewhere.
>
> What exactly constitutes a "text" file, and what is the basis for limiting
> things to that?

I'm not aware of any universal rigorous definition.  The C standard
(N1570 7.21.2p2) makes no guarantees for characters other than printable
characters, '\t', and '\n', or for space characters at the end of a
line.  Of course implementations can and do make further guarantees.

> At least in the MS-DOS world it was hardly uncommon to have files which
> contain mostly printable characters separated by newlines but also contain
> a few printer-setup codes, word-processor formatting codes, etc.  There's
> no particular reason something like a "grep" utility shouldn't be usable
> with such files.

And in fact GNU grep (to pick the example I'm most familiar with)
handles non-printable characters, including null characters, in a
reasonable way.  I'm sure the code that implements this handling is a
bit more complex than a more naive implementation would be.

>> And you don't want to discard the use of a fast strlen call because of 
>> that very rare possibility.
>
> Having to follow every fgets call with strlen is, at minimum, a nuisance
> compared with having a function which simply returns the proper information
> directly.

Every fgets call needs to be followed by a call to strlen *only* if you
always need to find and remove the '\n'.  That's not always necessary.

[...]

-- 
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"

Thread

Issues with setting variables to true or false: how does the compiler understands it Alla _ <modelling.data@gmail.com> - 2015-10-24 02:17 -0700
  Issues with setting variables to true or false: how does the compiler understands it asetofsymbols@gmail.com - 2015-10-24 03:29 -0700
    Re: Issues with setting variables to true or false: how does the compiler understands it Alla _ <modelling.data@gmail.com> - 2015-10-24 03:38 -0700
  Re: Issues with setting variables to true or false: how does the compiler understands it Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-24 04:30 -0700
    Re: Issues with setting variables to true or false: how does the compiler understands it gazelle@shell.xmission.com (Kenny McCormack) - 2015-10-24 12:04 +0000
  Issues with setting variables to true or false: how does the compiler understands it asetofsymbols@gmail.com - 2015-10-24 04:59 -0700
    Re: Issues with setting variables to true or false: how does the compiler understands it Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-24 14:28 +0100
      Re: Issues with setting variables to true or false: how does the compiler understands it asetofsymbols@gmail.com - 2015-10-24 07:26 -0700
        Re: Issues with setting variables to true or false: how does the compiler understands it Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-24 17:06 +0100
  Re: Issues with setting variables to true or false: how does the compiler understands it James Kuyper <jameskuyper@verizon.net> - 2015-10-24 11:56 -0400
    Re: Issues with setting variables to true or false: how does the compiler understands it Keith Thompson <kst-u@mib.org> - 2015-10-24 12:02 -0700
      Re: Issues with setting variables to true or false: how does the compiler understands it supercat@casperkitty.com - 2015-10-24 15:45 -0700
        Re: Issues with setting variables to true or false: how does the compiler understands it Keith Thompson <kst-u@mib.org> - 2015-10-24 16:28 -0700
          Re: Issues with setting variables to true or false: how does the compiler understands it Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-24 16:44 -0700
            Re: Issues with setting variables to true or false: how does the compiler understands it supercat@casperkitty.com - 2015-10-24 19:34 -0700
          Re: Issues with setting variables to true or false: how does the compiler understands it supercat@casperkitty.com - 2015-10-24 19:30 -0700
            Re: Issues with setting variables to true or false: how does the compiler understands it Keith Thompson <kst-u@mib.org> - 2015-10-24 20:33 -0700
          Re: Issues with setting variables to true or false: how does the compiler understands it Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-28 11:16 -0700
            Re: Issues with setting variables to true or false: how does the compiler understands it Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-28 15:12 -0400
              Re: Issues with setting variables to true or false: how does the compiler understands it Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-10-29 12:18 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it raltbos@xs4all.nl (Richard Bos) - 2015-10-29 21:51 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-30 08:38 -0700
              Re: Issues with setting variables to true or false: how does the compiler understands it Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-30 05:34 -0700
            Re: Issues with setting variables to true or false: how does the compiler understands it Keith Thompson <kst-u@mib.org> - 2015-10-28 14:08 -0700
              Re: Issues with setting variables to true or false: how does the compiler understands it Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-30 06:14 -0700
            Re: Issues with setting variables to true or false: how does the compiler understands it glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-28 21:50 +0000
              Re: Issues with setting variables to true or false: how does the compiler understands it supercat@casperkitty.com - 2015-10-28 15:08 -0700
                Re: Issues with setting variables to true or false: how does the compiler understands it glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-28 22:47 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it Robert Wessel <robertwessel2@yahoo.com> - 2015-10-28 18:35 -0500
                Re: Issues with setting variables to true or false: how does the compiler understands it supercat@casperkitty.com - 2015-10-28 18:12 -0700
                Re: Issues with setting variables to true or false: how does the compiler understands it glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-29 01:35 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it Robert Wessel <robertwessel2@yahoo.com> - 2015-10-28 21:12 -0500
                Re: Issues with setting variables to true or false: how does the compiler understands it supercat@casperkitty.com - 2015-10-28 19:52 -0700
                Re: Issues with setting variables to true or false: how does the compiler understands it supercat@casperkitty.com - 2015-10-28 18:01 -0700
              Re: Issues with setting variables to true or false: how does the compiler understands it Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-30 03:47 -0700
  Re: Issues with setting variables to true or false: how does the compiler understands it Barry Schwarz <schwarzb@dqel.com> - 2015-10-24 09:54 -0700
  Re: Issues with setting variables to true or false: how does the compiler understands it Keith Thompson <kst-u@mib.org> - 2015-10-24 12:13 -0700
  Re: Issues with setting variables to true or false: how does the compiler understands it Richard Heathfield <rjh@cpax.org.uk> - 2015-10-24 21:50 +0100
  Re: Issues with setting variables to true or false: how does the compiler understands it Alla _ <modelling.data@gmail.com> - 2015-10-25 04:04 -0700
    Re: Issues with setting variables to true or false: how does the compiler understands it Barry Schwarz <schwarzb@dqel.com> - 2015-10-25 08:32 -0700
      Re: Issues with setting variables to true or false: how does the compiler understands it Richard Heathfield <rjh@cpax.org.uk> - 2015-10-25 18:19 +0000
      Re: Issues with setting variables to true or false: how does the compiler understands it Alla _ <modelling.data@gmail.com> - 2015-10-25 11:30 -0700
        Re: Issues with setting variables to true or false: how does the compiler understands it Richard Heathfield <rjh@cpax.org.uk> - 2015-10-25 18:56 +0000
          Re: Issues with setting variables to true or false: how does the compiler understands it Alla _ <modelling.data@gmail.com> - 2015-10-25 20:59 -0700
            Re: Issues with setting variables to true or false: how does the compiler understands it Anand Hariharan <mailto.anand.hariharan@gmail.com> - 2015-10-25 21:49 -0700
              Re: Issues with setting variables to true or false: how does the compiler understands it Richard Heathfield <rjh@cpax.org.uk> - 2015-10-26 08:10 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it Anand Hariharan <mailto.anand.hariharan@gmail.com> - 2015-10-26 16:05 -0700
                Re: Issues with setting variables to true or false: how does the compiler understands it Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-27 00:34 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it Keith Thompson <kst-u@mib.org> - 2015-10-27 09:04 -0700
                Re: Issues with setting variables to true or false: how does the compiler understands it Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-27 21:24 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-26 18:16 -0700
                Re: Issues with setting variables to true or false: how does the compiler understands it Richard Heathfield <rjh@cpax.org.uk> - 2015-10-27 02:33 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it Keith Thompson <kst-u@mib.org> - 2015-10-27 09:08 -0700
          Re: Issues with setting variables to true or false: how does the compiler understands it Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-26 11:22 +0000
            Re: Issues with setting variables to true or false: how does the compiler understands it Richard Heathfield <rjh@cpax.org.uk> - 2015-10-26 11:35 +0000
              Re: Issues with setting variables to true or false: how does the compiler understands it Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-26 17:00 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it Richard Heathfield <rjh@cpax.org.uk> - 2015-10-26 17:59 +0000
          Re: Issues with setting variables to true or false: how does the compiler understands it Keith Thompson <kst-u@mib.org> - 2015-10-26 07:55 -0700
            Re: Issues with setting variables to true or false: how does the compiler understands it Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-26 17:06 +0000
            Re: Issues with setting variables to true or false: how does the compiler understands it supercat@casperkitty.com - 2015-10-26 10:56 -0700
            Re: Issues with setting variables to true or false: how does the compiler understands it glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-26 20:14 +0000
              Re: Issues with setting variables to true or false: how does the compiler understands it Keith Thompson <kst-u@mib.org> - 2015-10-26 17:09 -0700
          Re: Issues with setting variables to true or false: how does the compiler understands it Bartc <bc@freeuk.com> - 2015-10-26 23:39 +0000
            Re: Issues with setting variables to true or false: how does the compiler understands it Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-10-27 12:31 +0000
              Re: Issues with setting variables to true or false: how does the compiler understands it Richard Heathfield <rjh@cpax.org.uk> - 2015-10-27 12:45 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-27 13:24 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it Richard Heathfield <rjh@cpax.org.uk> - 2015-10-27 13:41 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-10-27 19:43 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-27 19:47 +0000
              Re: Issues with setting variables to true or false: how does the compiler understands it Bartc <bc@freeuk.com> - 2015-10-27 13:20 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it Richard Heathfield <rjh@cpax.org.uk> - 2015-10-27 13:28 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-27 13:54 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it supercat@casperkitty.com - 2015-10-27 07:51 -0700
                Re: Issues with setting variables to true or false: how does the compiler understands it Bartc <bc@freeuk.com> - 2015-10-27 16:46 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it supercat@casperkitty.com - 2015-10-27 10:52 -0700
                Re: Issues with setting variables to true or false: how does the compiler understands it Bartc <bc@freeuk.com> - 2015-10-27 18:51 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it supercat@casperkitty.com - 2015-10-27 12:17 -0700
                Re: Issues with setting variables to true or false: how does the compiler understands it Bartc <bc@freeuk.com> - 2015-10-27 19:34 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it supercat@casperkitty.com - 2015-10-27 13:10 -0700
                Re: Issues with setting variables to true or false: how does the compiler understands it Keith Thompson <kst-u@mib.org> - 2015-10-27 13:41 -0700
                Re: Issues with setting variables to true or false: how does the compiler understands it Bartc <bc@freeuk.com> - 2015-10-27 23:11 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it Keith Thompson <kst-u@mib.org> - 2015-10-27 19:02 -0700
                Re: Issues with setting variables to true or false: how does the compiler understands it gazelle@shell.xmission.com (Kenny McCormack) - 2015-10-28 07:09 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-10-28 11:27 +0000
                Re: Issues with setting variables to true or false: how does the compiler understands it Keith Thompson <kst-u@mib.org> - 2015-10-27 12:27 -0700
                Re: Issues with setting variables to true or false: how does the compiler understands it supercat@casperkitty.com - 2015-10-27 13:18 -0700

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