Re: Unspecified behavior in C

From	James Kuyper <jameskuyper@verizon.net>
Newsgroups	comp.lang.c
Subject	Re: Unspecified behavior in C
Date	2015-07-09 14:20 -0400
Organization	A noiseless patient Spider
Message-ID	<mnmdvn$krp$1@dont-email.me> (permalink)
References	(2 earlier) <ac8f0089-98d6-466a-afb2-eb5bfc12d88a@googlegroups.com> <lnoajmaatx.fsf@kst-u.example.com> <97928b10-0689-4a44-b516-56fdadf9e39a@googlegroups.com> <lnh9pea57n.fsf@kst-u.example.com> <cb5f75e3-44fb-484d-a017-47e53b339c53@googlegroups.com>

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On 07/09/2015 12:15 PM, David Kleinecke wrote:
...
> You are correct. I want all the "unspecified" behavior documented.
>
> My current hypothesis is that in the earlier drafts of the C90
> standard all the behavior now called implementation-defined was 
> called "unspecified". That later on the implementation-defined
> nomenclature was introduced - but not all instances of
> unspecified were updated. ...

I very much doubt that. I suspect that the writers of the C standard
made a decision in each case, while they were first writing it, which
terms to use - and frequently changed their minds during subsequent
discussions.

I can understand why someone who can't imagine why anything should be
left unspecified would think that it must have been done by mistake, but
I'm quite certain that the committee did it deliberately, for reasons
that made sense to them, and to me, if not to you.

...
> as I will say, I think a matter like whether "errno" is a macro is

The standard explicitly specifies that errno is a macro.

> already documented because what errno is is stated in the header
> <errno.h> ...

The text of errno.h (if it even exists - see below) is not considered
part of an implementation's documentation.

> ... which the user can read (in any sane development
> environment).

Standard headers need not be stored in header files, and the standard is
very carefully written to avoid mandating the existence of such files.
It always uses the term "header" to refer to the standard headers, and
"source file" to refer to user-provided files that are #included.  I
believe that there are real implementations which store only an internal
representation of each standard header in the compiler itself, rather
than storing them as separate text files. If there are separate text
files, they might be for documentation purposes only - if you had the
necessary permissions to modify them, it would have no affect on the
compilation of your programs, because it's only the purely internal
representations of the standard headers that matters.

The only things a user really needs to know about standard headers are
the things that can be found out by reading the C standard or by making
appropriate use of the macros #defined by those headers.
-- 
James Kuyper

Thread

Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-07 14:44 -0700
  Re: Unspecified behavior in C Keith Thompson <kst-u@mib.org> - 2015-07-07 15:34 -0700
    Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-08 08:47 -0700
      Re: Unspecified behavior in C Keith Thompson <kst-u@mib.org> - 2015-07-08 09:11 -0700
        Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-08 10:24 -0700
          Re: Unspecified behavior in C John Bode <jfbode1029@gmail.com> - 2015-07-08 10:46 -0700
          Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-08 13:54 -0400
          Re: Unspecified behavior in C Keith Thompson <kst-u@mib.org> - 2015-07-08 11:12 -0700
            Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-09 09:15 -0700
              Re: Unspecified behavior in C Richard Heathfield <rjh@cpax.org.uk> - 2015-07-09 17:33 +0100
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-10 09:24 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-10 12:54 -0400
              Re: Unspecified behavior in C Keith Thompson <kst-u@mib.org> - 2015-07-09 10:58 -0700
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-10 09:33 -0700
                Re: Unspecified behavior in C Keith Thompson <kst-u@mib.org> - 2015-07-10 12:11 -0700
                Re: Unspecified behavior in C glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-07-10 21:05 +0000
                Re: Unspecified behavior in C Keith Thompson <kst-u@mib.org> - 2015-07-10 17:14 -0700
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-11 09:32 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-11 12:59 -0400
                Re: Unspecified behavior in C Keith Thompson <kst-u@mib.org> - 2015-07-11 17:21 -0700
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-11 09:23 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-11 13:03 -0400
                Re: Unspecified behavior in C Keith Thompson <kst-u@mib.org> - 2015-07-11 17:15 -0700
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-12 09:52 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-12 14:13 -0400
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-13 09:02 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-13 13:18 -0400
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-13 11:09 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-13 15:06 -0400
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-14 08:14 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-14 12:02 -0400
                Re: Unspecified behavior in C Keith Thompson <kst-u@mib.org> - 2015-07-13 12:03 -0700
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-14 07:54 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-14 11:16 -0400
                Re: Unspecified behavior in C Richard Heathfield <rjh@cpax.org.uk> - 2015-07-14 16:17 +0100
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-14 09:16 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-14 12:29 -0400
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-14 14:57 -0400
                Re: Unspecified behavior in C Öö Tiib <ootiib@hot.ee> - 2015-07-14 13:12 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-14 16:30 -0400
                Re: Unspecified behavior in C Öö Tiib <ootiib@hot.ee> - 2015-07-14 15:54 -0700
                Re: Unspecified behavior in C Morris Dovey <mrdovey@iedu.com> - 2015-07-14 21:41 -0500
                Re: Unspecified behavior in C Morris Dovey <mrdovey@iedu.com> - 2015-07-14 21:51 -0500
                Re: Unspecified behavior in C Öö Tiib <ootiib@hot.ee> - 2015-07-15 12:42 -0700
                Re: Unspecified behavior in C Morris Dovey <mrdovey@iedu.com> - 2015-07-15 16:13 -0500
                Re: Unspecified behavior in C Morris Dovey <mrdovey@iedu.com> - 2015-07-16 08:49 -0500
                Re: Unspecified behavior in C Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-20 10:10 -0700
                Re: Unspecified behavior in C Morris Dovey <mrdovey@iedu.com> - 2015-07-20 13:24 -0500
                Re: Unspecified behavior in C Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-23 02:56 -0700
                Re: Unspecified behavior in C Morris Dovey <mrdovey@iedu.com> - 2015-07-23 11:26 -0500
                Re: Unspecified behavior in C Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-26 11:24 -0700
                Re: Unspecified behavior in C Morris Dovey <mrdovey@iedu.com> - 2015-07-23 19:03 -0500
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-15 21:19 -0700
                Re: Unspecified behavior in C Martin Shobe <martin.shobe@yahoo.com> - 2015-07-15 23:45 -0500
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-16 01:37 -0400
                Re: Unspecified behavior in C Richard Heathfield <rjh@cpax.org.uk> - 2015-07-16 09:42 +0100
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-16 17:05 -0700
                Re: Unspecified behavior in C Richard Heathfield <rjh@cpax.org.uk> - 2015-07-17 01:32 +0100
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-16 21:07 -0400
                We're good - don't you worry 'bout a thing, babe (Was: Unspecified behavior in C) gazelle@shell.xmission.com (Kenny McCormack) - 2015-07-17 07:21 +0000
                Re: Unspecified behavior in C raltbos@xs4all.nl (Richard Bos) - 2015-07-19 20:59 +0000
                Re: Unspecified behavior in C Richard Heathfield <rjh@cpax.org.uk> - 2015-07-19 22:02 +0100
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-16 17:59 -0400
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-16 23:09 -0400
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-17 18:48 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-17 23:09 -0400
                Re: Unspecified behavior in C raltbos@xs4all.nl (Richard Bos) - 2015-07-19 20:57 +0000
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-19 17:22 -0400
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-19 18:57 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-19 22:16 -0400
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-19 19:30 -0700
                Re: Unspecified behavior in C John Bode <jfbode1029@gmail.com> - 2015-07-30 14:20 -0700
                Re: Unspecified behavior in C Keith Thompson <kst-u@mib.org> - 2015-07-30 15:30 -0700
                Re: Unspecified behavior in C John Bode <jfbode1029@gmail.com> - 2015-07-30 15:53 -0700
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-30 16:46 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-31 00:59 -0400
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-31 17:15 -0700
                Re: Unspecified behavior in C Keith Thompson <kst-u@mib.org> - 2015-07-31 18:28 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-31 23:28 -0400
                Re: Unspecified behavior in C Tim Rentsch <txr@alumni.caltech.edu> - 2015-08-04 04:07 -0700
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-08-04 18:02 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-08-04 21:27 -0400
                Re: Unspecified behavior in C Tim Rentsch <txr@alumni.caltech.edu> - 2015-08-24 09:33 -0700
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-08-24 17:11 -0700
                Re: Unspecified behavior in C Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-06 12:44 -0700
                Re: Unspecified behavior in C Ken Brody <kenbrody@spamcop.net> - 2015-08-03 12:09 -0400
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-08-03 13:26 -0400
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-08-03 17:53 -0700
                Re: Unspecified behavior in C Keith Thompson <kst-u@mib.org> - 2015-08-03 18:44 -0700
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-08-04 17:59 -0700
                Re: Unspecified behavior in C Richard Heathfield <rjh@cpax.org.uk> - 2015-08-05 02:23 +0100
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-08-04 21:39 -0400
                Re: Unspecified behavior in C Keith Thompson <kst-u@mib.org> - 2015-08-04 19:27 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-08-04 00:25 -0400
                Re: Unspecified behavior in C Ken Brody <kenbrody@spamcop.net> - 2015-08-04 11:55 -0400
                Re: Unspecified behavior in C Philip Lantz <prl@canterey.us> - 2015-08-04 10:31 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-08-04 13:32 -0400
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-08-04 22:46 -0400
                Re: Unspecified behavior in C Ken Brody <kenbrody@spamcop.net> - 2015-08-10 12:16 -0400
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-08-10 13:26 -0400
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-08-03 17:46 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-08-05 12:34 -0400
                Re: Unspecified behavior in C Richard Heathfield <rjh@cpax.org.uk> - 2015-07-14 17:57 +0100
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-14 10:31 -0700
                Re: Unspecified behavior in C Richard Heathfield <rjh@cpax.org.uk> - 2015-07-14 18:50 +0100
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-15 20:59 -0700
                Re: Unspecified behavior in C Keith Thompson <kst-u@mib.org> - 2015-07-14 11:34 -0700
                Re: Unspecified behavior in C raltbos@xs4all.nl (Richard Bos) - 2015-07-19 20:46 +0000
                Re: Unspecified behavior in C Keith Thompson <kst-u@mib.org> - 2015-07-12 12:07 -0700
                Re: Unspecified behavior in C glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-07-12 19:53 +0000
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-12 16:12 -0400
              Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-09 14:20 -0400
                Re: Unspecified behavior in C Keith Thompson <kst-u@mib.org> - 2015-07-09 12:18 -0700
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-10 09:47 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-10 13:36 -0400
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-11 09:19 -0700
                Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-11 12:56 -0400
                Re: Unspecified behavior in C gordonb.j19di@burditt.org (Gordon Burditt) - 2015-07-11 20:36 -0500
                Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-12 10:10 -0700
              Re: Unspecified behavior in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-07-09 20:13 +0100
          Re: Unspecified behavior in C raltbos@xs4all.nl (Richard Bos) - 2015-07-09 11:17 +0000
        Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-08 10:37 -0700
          Re: Unspecified behavior in C John Bode <jfbode1029@gmail.com> - 2015-07-08 10:51 -0700
          Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-08 14:14 -0400
          Re: Unspecified behavior in C Keith Thompson <kst-u@mib.org> - 2015-07-08 12:19 -0700
      Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-08 12:14 -0400
        Re: Unspecified behavior in C David Kleinecke <dkleinecke@gmail.com> - 2015-07-08 10:40 -0700
          Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-08 14:29 -0400
            Re: Unspecified behavior in C raltbos@xs4all.nl (Richard Bos) - 2015-07-09 11:20 +0000
      Re: Unspecified behavior in C Robert Wessel <robertwessel2@yahoo.com> - 2015-07-09 02:30 -0500
  Re: Unspecified behavior in C James Kuyper <jameskuyper@verizon.net> - 2015-07-07 22:30 -0400

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