Re: More physical source files

From	Keith Thompson <kst-u@mib.org>
Newsgroups	comp.lang.c
Subject	Re: More physical source files
Date	2015-07-03 10:05 -0700
Organization	None to speak of
Message-ID	<ln4mll18ak.fsf@kst-u.example.com> (permalink)
References	(6 earlier) <56d054c6-5316-46eb-b7b4-686bd405149d@googlegroups.com> <lnmvzf21kt.fsf@kst-u.example.com> <de40dc32-3557-4219-8eb8-c40d5481694d@googlegroups.com> <lnegkq160c.fsf@kst-u.example.com> <39cf9193-5d10-4db9-b766-9452d7c1b0bf@googlegroups.com>

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David Kleinecke <dkleinecke@gmail.com> writes:
> On Thursday, July 2, 2015 at 4:42:28 PM UTC-7, Keith Thompson wrote:
[...]
>> A conforming compiler is not permitted to reject a program because it's
>> not strictly conforming.
>> 
>> The definition of a strictly conforming program is (N1570 4p5):
>> 
>>     A strictly conforming program shall use only those features
>>     of the language and library specified in this International
>>     Standard. It shall not produce output dependent on any
>>     unspecified, undefined, or implementation-defined behavior,
>>     and shall not exceed any minimum implementation limit.
>> 
>> But (N1570 4p3):
>> 
>>     A program that is correct in all other aspects, operating on
>>     correct data, containing unspecified behavior shall be a correct
>>     program and act in accordance with 5.1.2.3.
>  
> Once again this paragraph is not in the C90 standard (so far as I 
> can tell). I don't think the C90 standard has a concept of "correct
> program". 

That paragraph was added in C99.

The C90 standard is obsolete, superseded by C99 and later by C11.

I don't believe it was ever the intent that a C compiler could
reject a program because it's not strictly conforming.  That intent
was made explicit in the C99 standard.

> I hadn't noticed this before. Appendix G.1 of the C90 standard lists
> 22 unspecified features. Appendix J.1 of N1570 has many more. One item 
> is "floating type representation". Doesn't that mean that a strictly
> conforming program cannot use floating types? 
>
> If so the floating types are essentially excluded from strict
> conformity. I haven't thought this through - what exactly does  
> "not produce output dependent on any unspecified ... behavior"
> mean?

The representation of floating-point objects is a separate issue from
the behavior of floating-point operations.

A program that outputs the raw representation of a floating-point object
cannot be strictly conforming.  A program that uses floating-point can
be strictly conforming, as long as its output doesn't depend on any
unspecified behavior.

-- 
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

More physical source files David Kleinecke <dkleinecke@gmail.com> - 2015-06-27 11:19 -0700
  Re: More physical source files Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-06-27 11:54 -0700
    Re: More physical source files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-06-27 21:20 +0100
  Re: More physical source files Bartc <bc@freeuk.com> - 2015-06-27 20:24 +0100
    Re: More physical source files David Kleinecke <dkleinecke@gmail.com> - 2015-06-29 07:14 -0700
      Re: More physical source files Keith Thompson <kst-u@mib.org> - 2015-06-29 08:16 -0700
        Re: More physical source files David Kleinecke <dkleinecke@gmail.com> - 2015-06-30 08:24 -0700
          Re: More physical source files Robert Wessel <robertwessel2@yahoo.com> - 2015-06-30 12:15 -0500
          Re: More physical source files Keith Thompson <kst-u@mib.org> - 2015-06-30 15:14 -0700
            Re: More physical source files David Kleinecke <dkleinecke@gmail.com> - 2015-07-01 08:38 -0700
              Re: More physical source files glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-07-01 16:43 +0000
                Re: More physical source files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-07-01 18:52 +0100
                Re: More physical source files Keith Thompson <kst-u@mib.org> - 2015-07-01 11:21 -0700
                Re: More physical source files glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-07-01 18:36 +0000
                Re: More physical source files Richard Damon <Richard@Damon-Family.org> - 2015-07-01 22:33 -0400
                Re: More physical source files glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-07-02 19:11 +0000
              Re: More physical source files Keith Thompson <kst-u@mib.org> - 2015-07-01 11:08 -0700
                Re: More physical source files Richard Damon <Richard@Damon-Family.org> - 2015-07-01 22:30 -0400
                Re: More physical source files David Kleinecke <dkleinecke@gmail.com> - 2015-07-02 08:29 -0700
                Re: More physical source files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-07-02 17:56 +0100
                Re: More physical source files James Kuyper <jameskuyper@verizon.net> - 2015-07-02 13:21 -0400
                Re: More physical source files David Kleinecke <dkleinecke@gmail.com> - 2015-07-03 08:54 -0700
                Re: More physical source files James Kuyper <jameskuyper@verizon.net> - 2015-07-04 12:23 -0400
                Re: More physical source files Martin Shobe <martin.shobe@yahoo.com> - 2015-07-04 11:36 -0500
                Re: More physical source files Keith Thompson <kst-u@mib.org> - 2015-07-02 16:42 -0700
                Re: More physical source files David Kleinecke <dkleinecke@gmail.com> - 2015-07-03 08:54 -0700
                Re: More physical source files Keith Thompson <kst-u@mib.org> - 2015-07-03 10:05 -0700
                Re: More physical source files glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-07-03 21:57 +0000
                Re: More physical source files James Kuyper <jameskuyper@verizon.net> - 2015-07-04 00:30 -0400
                Re: More physical source files David Kleinecke <dkleinecke@gmail.com> - 2015-07-04 08:08 -0700
                Re: More physical source files Richard Damon <Richard@Damon-Family.org> - 2015-07-04 12:21 -0400
                Re: More physical source files David Kleinecke <dkleinecke@gmail.com> - 2015-07-05 09:22 -0700
                Re: More physical source files David Kleinecke <dkleinecke@gmail.com> - 2015-07-05 09:49 -0700
                Re: More physical source files Keith Thompson <kst-u@mib.org> - 2015-07-05 18:16 -0700
                Re: More physical source files David Kleinecke <dkleinecke@gmail.com> - 2015-07-06 08:37 -0700
                Re: More physical source files James Kuyper <jameskuyper@verizon.net> - 2015-07-06 12:56 -0400
                Re: More physical source files Keith Thompson <kst-u@mib.org> - 2015-07-06 11:59 -0700
                Re: More physical source files James Kuyper <jameskuyper@verizon.net> - 2015-07-06 15:45 -0400
                Re: More physical source files Keith Thompson <kst-u@mib.org> - 2015-07-06 13:14 -0700
                Re: More physical source files Philip Lantz <prl@canterey.us> - 2015-07-07 01:10 -0700
                Re: More physical source files David Kleinecke <dkleinecke@gmail.com> - 2015-07-07 08:00 -0700
                Re: More physical source files David Kleinecke <dkleinecke@gmail.com> - 2015-07-07 07:55 -0700
                Re: More physical source files James Kuyper <jameskuyper@verizon.net> - 2015-07-07 13:13 -0400
                Re: More physical source files David Kleinecke <dkleinecke@gmail.com> - 2015-07-08 08:35 -0700
                Re: More physical source files James Kuyper <jameskuyper@verizon.net> - 2015-07-08 12:31 -0400
                Re: More physical source files David Kleinecke <dkleinecke@gmail.com> - 2015-07-09 08:50 -0700
                Re: More physical source files Richard Heathfield <rjh@cpax.org.uk> - 2015-07-09 16:56 +0100
                Re: More physical source files Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-09 13:31 -0700
                Re: More physical source files Keith Thompson <kst-u@mib.org> - 2015-07-09 15:03 -0700
                Re: More physical source files Ian Collins <ian-news@hotmail.com> - 2015-07-10 10:54 +1200
                Re: More physical source files James Kuyper <jameskuyper@verizon.net> - 2015-07-09 14:32 -0400
                Re: More physical source files James Kuyper <jameskuyper@verizon.net> - 2015-07-05 13:41 -0400
                Re: More physical source files Richard Damon <Richard@Damon-Family.org> - 2015-07-05 14:17 -0400
                Re: More physical source files Keith Thompson <kst-u@mib.org> - 2015-07-04 12:36 -0700
                Re: More physical source files Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-04 15:19 -0700
                Re: More physical source files Keith Thompson <kst-u@mib.org> - 2015-07-04 15:42 -0700
                Re: More physical source files James Kuyper <jameskuyper@verizon.net> - 2015-07-04 19:04 -0400
                Re: More physical source files Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-05 03:25 -0700
                Re: More physical source files Keith Thompson <kst-u@mib.org> - 2015-07-05 09:18 -0700
                Re: More physical source files James Kuyper <jameskuyper@verizon.net> - 2015-07-05 14:11 -0400
                Re: More physical source files Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-05 13:41 -0700
                Re: More physical source files James Kuyper <jameskuyper@verizon.net> - 2015-07-04 12:50 -0400
      Re: More physical source files Bartc <bc@freeuk.com> - 2015-06-29 17:20 +0100
  Re: More physical source files Rosario19 <Ros@invalid.invalid> - 2015-06-28 11:57 +0200

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