Re: Sequence points and commit to memory

From	James Kuyper <jameskuyper@verizon.net>
Newsgroups	comp.lang.c
Subject	Re: Sequence points and commit to memory
Date	2015-05-19 12:10 -0400
Organization	Self
Message-ID	<555B6075.6020403@verizon.net> (permalink)
References	(8 earlier) <mjdouv$gdj$2@dont-email.me> <555A7049.6010405@verizon.net> <mjdv04$3k5$1@speranza.aioe.org> <mjea5a$v64$1@dont-email.me> <mjel16$ats$1@speranza.aioe.org>

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On 05/19/2015 02:25 AM, glen herrmannsfeldt wrote:
> James Kuyper <jameskuyper@verizon.net> wrote:
> 
> (snip)
>>>> On a platform which supports interrupts, a conforming implementation of
>>>> C must generate code that will still produce the behavior defined by the
>>>> standard for the source code. 
> 
> (snip, then I wrote)
>>> How about on CPUs that support imprecise interrupts?
>  
>> I'm unfamiliar with that term. Is there any conceivable method to
>> generate code that has the behavior defined by the standard, even if
>> execution of that code is interrupted by imprecise interrupts? 
> 
> Imprecise interrupts occur on processors with out-of-order execution
> and, further, out-of-order retirement. (Many processors now have
> out-of-order execution, but manage to arrange things such that the
> effects happen in order.)
> 
>> If so,
>> whatever approach needs to be taken to achieve that result is mandatory
>> for conforming implementations of C on those platforms. If not,
>> conforming implementations of C are not possible on those platforms.
> 
> I suspect that the causes of imprecise interrupts already cause UB,
> such that it doesn't matter. They do make debugging harder, though.

In that case, the standard imposes no restrictions on the behavior of
the program, making it trivial to satisfies the standard's requirements,
so a conforming implementation of C doesn't have to worry about them. It
follows that they won't occur in strictly conforming code, so they pose
no problems that matter to such code.

Thread

Sequence points and commit to memory "James Harris" <james.harris.1@gmail.com> - 2015-05-14 11:43 +0100
  Re: Sequence points and commit to memory Richard Heathfield <rjh@cpax.org.uk> - 2015-05-14 12:02 +0100
    Re: Sequence points and commit to memory David Brown <david.brown@hesbynett.no> - 2015-05-14 13:39 +0200
      Re: Sequence points and commit to memory Richard Heathfield <rjh@cpax.org.uk> - 2015-05-14 13:18 +0100
        Re: Sequence points and commit to memory David Brown <david.brown@hesbynett.no> - 2015-05-14 23:11 +0200
  Re: Sequence points and commit to memory Stephen Sprunk <stephen@sprunk.org> - 2015-05-14 09:06 -0500
  Re: Sequence points and commit to memory Siri Cruz <chine.bleu@yahoo.com> - 2015-05-14 08:35 -0700
    Re: Sequence points and commit to memory David Kleinecke <dkleinecke@gmail.com> - 2015-05-14 10:23 -0700
      Re: Sequence points and commit to memory Siri Cruz <chine.bleu@yahoo.com> - 2015-05-14 10:44 -0700
        Re: Sequence points and commit to memory David Kleinecke <dkleinecke@gmail.com> - 2015-05-14 11:09 -0700
          Re: Sequence points and commit to memory Keith Thompson <kst-u@mib.org> - 2015-05-14 12:58 -0700
          Re: Sequence points and commit to memory Morris Dovey <mrdovey@iedu.com> - 2015-05-14 16:31 -0500
            Re: Sequence points and commit to memory Keith Thompson <kst-u@mib.org> - 2015-05-14 17:24 -0700
              Re: Sequence points and commit to memory Morris Dovey <mrdovey@iedu.com> - 2015-05-14 20:18 -0500
                Re: Sequence points and commit to memory David Brown <david.brown@hesbynett.no> - 2015-05-15 09:34 +0200
                Re: Sequence points and commit to memory Morris Dovey <mrdovey@iedu.com> - 2015-05-15 10:18 -0500
                Re: 'register' attribute (was: Sequence points and commit to memory) Morris Dovey <mrdovey@iedu.com> - 2015-05-16 01:26 -0500
                Re: 'register' attribute David Brown <david.brown@hesbynett.no> - 2015-05-17 00:02 +0200
                Re: 'register' attribute Morris Dovey <mrdovey@iedu.com> - 2015-05-16 19:29 -0500
            Re: Sequence points and commit to memory David Kleinecke <dkleinecke@gmail.com> - 2015-05-15 09:52 -0700
              Re: Sequence points and commit to memory James Kuyper <jameskuyper@verizon.net> - 2015-05-15 13:27 -0400
                Re: Sequence points and commit to memory Keith Thompson <kst-u@mib.org> - 2015-05-15 10:50 -0700
              Re: Sequence points and commit to memory Morris Dovey <mrdovey@iedu.com> - 2015-05-15 12:32 -0500
      Re: Sequence points and commit to memory David Brown <david.brown@hesbynett.no> - 2015-05-14 23:23 +0200
        Re: Sequence points and commit to memory David Kleinecke <dkleinecke@gmail.com> - 2015-05-15 09:42 -0700
          Re: Sequence points and commit to memory James Kuyper <jameskuyper@verizon.net> - 2015-05-15 13:13 -0400
            Re: Sequence points and commit to memory David Kleinecke <dkleinecke@gmail.com> - 2015-05-16 08:32 -0700
          Re: Sequence points and commit to memory Keith Thompson <kst-u@mib.org> - 2015-05-15 10:35 -0700
          Re: Sequence points and commit to memory Keith Thompson <kst-u@mib.org> - 2015-05-15 11:08 -0700
            Re: Sequence points and commit to memory Robert Wessel <robertwessel2@yahoo.com> - 2015-05-15 16:40 -0500
            Re: Sequence points and commit to memory David Kleinecke <dkleinecke@gmail.com> - 2015-05-16 08:48 -0700
          Re: Sequence points and commit to memory "James Harris" <james.harris.1@gmail.com> - 2015-05-15 21:46 +0100
            Re: Sequence points and commit to memory David Kleinecke <dkleinecke@gmail.com> - 2015-05-16 08:56 -0700
              Re: Sequence points and commit to memory "James Harris" <james.harris.1@gmail.com> - 2015-05-16 19:35 +0100
                Re: Sequence points and commit to memory David Kleinecke <dkleinecke@gmail.com> - 2015-05-18 09:49 -0700
                Re: Sequence points and commit to memory "James Harris" <james.harris.1@gmail.com> - 2015-05-19 09:04 +0100
                Re: Sequence points and commit to memory Keith Thompson <kst-u@mib.org> - 2015-05-19 08:42 -0700
    Re: Sequence points and commit to memory "James Harris" <james.harris.1@gmail.com> - 2015-05-14 22:00 +0100
      Re: Sequence points and commit to memory Siri Cruz <chine.bleu@yahoo.com> - 2015-05-14 14:26 -0700
        Re: Sequence points and commit to memory "James Harris" <james.harris.1@gmail.com> - 2015-05-14 22:33 +0100
      Re: Sequence points and commit to memory David Brown <david.brown@hesbynett.no> - 2015-05-14 23:38 +0200
        Re: Sequence points and commit to memory "James Harris" <james.harris.1@gmail.com> - 2015-05-14 23:04 +0100
          Re: Sequence points and commit to memory Stephen Sprunk <stephen@sprunk.org> - 2015-05-15 13:09 -0500
            Re: Sequence points and commit to memory "James Harris" <james.harris.1@gmail.com> - 2015-05-15 21:56 +0100
              Re: Sequence points and commit to memory James Kuyper <jameskuyper@verizon.net> - 2015-05-15 17:30 -0400
                Re: Sequence points and commit to memory "James Harris" <james.harris.1@gmail.com> - 2015-05-16 07:51 +0100
                Re: Sequence points and commit to memory James Kuyper <jameskuyper@verizon.net> - 2015-05-16 22:10 -0400
                Re: Sequence points and commit to memory David Brown <david.brown@hesbynett.no> - 2015-05-19 00:25 +0200
                Re: Sequence points and commit to memory James Kuyper <jameskuyper@verizon.net> - 2015-05-18 18:55 -0400
                Re: Sequence points and commit to memory David Brown <david.brown@hesbynett.no> - 2015-05-19 09:10 +0200
                Re: Sequence points and commit to memory James Kuyper <jameskuyper@verizon.net> - 2015-05-19 12:05 -0400
                Re: Sequence points and commit to memory David Brown <david.brown@hesbynett.no> - 2015-05-19 18:42 +0200
              Re: Sequence points and commit to memory Stephen Sprunk <stephen@sprunk.org> - 2015-05-16 16:33 -0500
                Re: Sequence points and commit to memory David Brown <david.brown@hesbynett.no> - 2015-05-19 00:27 +0200
                Re: Sequence points and commit to memory James Kuyper <jameskuyper@verizon.net> - 2015-05-18 19:05 -0400
                Re: Sequence points and commit to memory glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-05-19 00:09 +0000
                Re: Sequence points and commit to memory Richard Heathfield <rjh@cpax.org.uk> - 2015-05-19 01:11 +0100
                Re: Sequence points and commit to memory Tim Rentsch <txr@alumni.caltech.edu> - 2015-05-23 07:02 -0700
                Re: Sequence points and commit to memory James Kuyper <jameskuyper@verizon.net> - 2015-05-18 23:21 -0400
                Re: Sequence points and commit to memory glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-05-19 06:25 +0000
                Re: Sequence points and commit to memory David Brown <david.brown@hesbynett.no> - 2015-05-19 08:58 +0200
                Re: Sequence points and commit to memory glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-05-19 23:20 +0000
                Re: Sequence points and commit to memory David Brown <david.brown@hesbynett.no> - 2015-05-20 12:31 +0200
                Re: Sequence points and commit to memory James Kuyper <jameskuyper@verizon.net> - 2015-05-19 12:10 -0400
                Re: Sequence points and commit to memory glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-05-19 23:24 +0000
                Re: Sequence points and commit to memory David Brown <david.brown@hesbynett.no> - 2015-05-19 09:05 +0200
                Re: Sequence points and commit to memory Keith Thompson <kst-u@mib.org> - 2015-05-19 08:37 -0700
                Re: Sequence points and commit to memory James Kuyper <jameskuyper@verizon.net> - 2015-05-19 12:14 -0400
                Re: Sequence points and commit to memory David Brown <david.brown@hesbynett.no> - 2015-05-19 19:02 +0200
            Re: Sequence points and commit to memory Robert Wessel <robertwessel2@yahoo.com> - 2015-05-15 16:46 -0500
          Re: Sequence points and commit to memory David Brown <david.brown@hesbynett.no> - 2015-05-17 00:20 +0200
            Re: Sequence points and commit to memory "James Harris" <james.harris.1@gmail.com> - 2015-05-17 18:19 +0100
              Re: Sequence points and commit to memory Philip Lantz <prl@canterey.us> - 2015-05-17 16:11 -0700
                Re: Sequence points and commit to memory "James Harris" <james.harris.1@gmail.com> - 2015-05-18 08:30 +0100
                Re: Sequence points and commit to memory David Kleinecke <dkleinecke@gmail.com> - 2015-05-18 10:31 -0700
                Re: Sequence points and commit to memory Keith Thompson <kst-u@mib.org> - 2015-05-18 11:11 -0700
                Re: Sequence points and commit to memory David Kleinecke <dkleinecke@gmail.com> - 2015-05-19 09:37 -0700
                Re: Sequence points and commit to memory Ian Collins <ian-news@hotmail.com> - 2015-05-19 17:40 +1200
                Re: Sequence points and commit to memory Morris Dovey <mrdovey@iedu.com> - 2015-05-19 01:31 -0500
                Re: Sequence points and commit to memory Ian Collins <ian-news@hotmail.com> - 2015-05-19 20:38 +1200
                Re: Sequence points and commit to memory Morris Dovey <mrdovey@iedu.com> - 2015-05-19 10:50 -0500
                Re: Sequence points and commit to memory David Brown <david.brown@hesbynett.no> - 2015-05-19 00:46 +0200
              Re: Sequence points and commit to memory David Brown <david.brown@hesbynett.no> - 2015-05-19 00:35 +0200
      Re: Sequence points and commit to memory Robert Wessel <robertwessel2@yahoo.com> - 2015-05-15 16:42 -0500
        Re: Sequence points and commit to memory "James Harris" <james.harris.1@gmail.com> - 2015-05-16 07:58 +0100
          Re: Sequence points and commit to memory Robert Wessel <robertwessel2@yahoo.com> - 2015-05-16 02:18 -0500
            Re: Sequence points and commit to memory "James Harris" <james.harris.1@gmail.com> - 2015-05-16 08:36 +0100
              Re: Sequence points and commit to memory Robert Wessel <robertwessel2@yahoo.com> - 2015-05-17 04:31 -0500
                Re: Sequence points and commit to memory "James Harris" <james.harris.1@gmail.com> - 2015-05-17 18:24 +0100
                Re: Sequence points and commit to memory David Brown <david.brown@hesbynett.no> - 2015-05-19 00:55 +0200
  Re: Sequence points and commit to memory Keith Thompson <kst-u@mib.org> - 2015-05-14 11:26 -0700
    Re: Sequence points and commit to memory "James Harris" <james.harris.1@gmail.com> - 2015-05-14 22:07 +0100
      Re: Sequence points and commit to memory Keith Thompson <kst-u@mib.org> - 2015-05-14 14:22 -0700
        Re: Sequence points and commit to memory "James Harris" <james.harris.1@gmail.com> - 2015-05-14 22:36 +0100
    Re: Sequence points and commit to memory Tim Rentsch <txr@alumni.caltech.edu> - 2015-05-22 08:16 -0700
      Re: Sequence points and commit to memory Keith Thompson <kst-u@mib.org> - 2015-05-22 11:31 -0700
  Re: Sequence points and commit to memory James Kuyper <jameskuyper@verizon.net> - 2015-05-15 00:05 -0400
    Re: Sequence points and commit to memory "James Harris" <james.harris.1@gmail.com> - 2015-05-15 22:25 +0100
      Re: Sequence points and commit to memory James Kuyper <jameskuyper@verizon.net> - 2015-05-15 17:56 -0400
  Re: Sequence points and commit to memory Nobody <nobody@nowhere.invalid> - 2015-05-17 10:04 +0100
  Re: Sequence points and commit to memory Tim Rentsch <txr@alumni.caltech.edu> - 2015-05-24 08:11 -0700

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