Re: Getting started with AVR and C

From	James Kuyper <jameskuyper@verizon.net>
Newsgroups	comp.arch.embedded, comp.lang.c
Subject	Re: Getting started with AVR and C
Date	2012-11-29 22:46 -0500
Organization	A noiseless patient Spider
Message-ID	<k99a7e$cr2$1@dont-email.me> (permalink)
References	(9 earlier) <k96he8$m87$1@speranza.aioe.org> <OdWdnXwRtuUQvSrNnZ2dnUVZ8uSdnZ2d@lyse.net> <k97q71$hn3$1@dont-email.me> <k97qpg$lci$1@dont-email.me> <50B7EEF8.29B9@mindspring.com>

Cross-posted to 2 groups.

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On 11/29/2012 06:25 PM, pete wrote:
> James Kuyper wrote:
>>
>> On 11/29/2012 09:07 AM, James Kuyper wrote:
>> ...
>>> "If an int can represent all values of the original type
>>> (as restricted
>>> by the width, for a bit-field), the value is converted to an int;
>>> otherwise, it is converted to an unsigned int. These are called the
>>> integer promotions.58) All other types are unchanged by the integer
>>> promotions."
>>> (6.3.1.1p2) The first use of "integer promotions" in that
>>> clause is italicized, which is an ISO convention indicating
>>> that the
>>> sentence containing that phrase serves
>>> as the definition of the phrase.
>>
>> I just realized that the meaning of the phrase "All other types"
>> is not
>> clear without the preceding part of that clause which I snipped:
>>
>>> The following may be used in an expression
>>> wherever an int or unsigned int may
>>> be used:
>>> — An object or expression with an integer type
>>> (other than int or unsigned int)
>>> whose integer conversion rank is less than
>>> or equal to the rank of int and unsigned int.
>>> —
>>> A bit-field of type _Bool, int, signed int, or unsigned int.
> 
> I recall reading some posts in this newsgroup a long time ago,
> which claimed that under certain circumstances,
> that it was possible in C99,
> for unsigned int to promote to type signed int.

An unsigned type whose entire range can be represented by an int will
promote to signed int, as can easily be confirmed by checking the above
text, and that point has been raised in this group - there were several
threads that touched on that subject in just this past summer. However,
 anyone who claimed that it could happen to "unsigned int" was mistaken.
That clause explicitly applies only to types "other than int or unsigned
int".

> But that was never the case. 
> 
> In C99
> 6.3.1.1 paragraph 2, read as "less than"
> instead of "less than or equal" as you have above;
> and unsigned int type was covered by "All other types"
> in the last sentence.

n1256.pdf (which is C99 with all three TCs applied, making it MORE
useful than C99 itself) and n1570.pdf (which is essentially identical to
C2011) both have "less than or equal to". The line is marked as being
changed from C99 in n1256.pdf, implying that one of the TCs is the
reason. My copy of C99 itself is inaccessible right now, so I can't
confirm the nature of the change.
-- 
James Kuyper

Thread

Getting started with AVR and C Robert Roland <fake@ddress.no> - 2012-11-24 17:41 +0100
  Re: Getting started with AVR and C hamilton <hamilton@nothere.com> - 2012-11-24 09:55 -0700
    Re: Getting started with AVR and C David Brown <david.brown@removethis.hesbynett.no> - 2012-11-25 10:39 +0100
  Re: Getting started with AVR and C Rene <a@b.c> - 2012-11-24 18:03 +0100
    Re: Getting started with AVR and C Rene <a@b.c> - 2012-12-10 13:21 +0100
      Re: Getting started with AVR and C Christopher Head <chead@is.invalid> - 2012-12-10 18:33 -0800
        Re: Getting started with AVR and C Rene <a@b.c> - 2012-12-11 12:34 +0100
  Re: Getting started with AVR and C Tim Wescott <tim@seemywebsite.please> - 2012-11-24 12:44 -0600
  Re: Getting started with AVR and C me@linnix.info-for.us - 2012-11-24 11:12 -0800
  Re: Getting started with AVR and C mike <ham789@netzero.net> - 2012-11-24 11:28 -0800
    Re: Getting started with AVR and C me@linnix.info-for.us - 2012-11-24 11:42 -0800
      Re: Getting started with AVR and C mike <ham789@netzero.net> - 2012-11-25 07:01 -0800
    Re: Getting started with AVR and C David Brown <david.brown@removethis.hesbynett.no> - 2012-11-25 20:14 +0100
  Re: Getting started with AVR and C Ivan Shmakov <oneingray@gmail.com> - 2012-11-25 03:18 +0700
  Re: Getting started with AVR and C Ivan Shmakov <oneingray@gmail.com> - 2012-11-25 04:18 +0700
    Re: Getting started with AVR and C Richard Damon <news.x.richarddamon@xoxy.net> - 2012-11-24 17:09 -0500
    Re: Getting started with AVR and C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-11-24 22:12 +0000
      Re: Getting started with AVR and C Dave Nadler <drn@nadler.com> - 2012-11-24 21:01 -0800
        statement / expression contexts in C Ivan Shmakov <oneingray@gmail.com> - 2012-11-28 12:54 +0700
      Re: Getting started with AVR and C Ivan Shmakov <oneingray@gmail.com> - 2012-11-28 13:37 +0700
        Re: Getting started with AVR and C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-11-28 14:49 +0000
        Re: Getting started with AVR and C Frank Miles <fpm@u.washington.edu> - 2012-11-28 17:53 +0000
          Re: Getting started with AVR and C Grant Edwards <invalid@invalid.invalid> - 2012-11-28 18:05 +0000
            Re: Getting started with AVR and C Tim Wescott <tim@seemywebsite.com> - 2012-11-28 12:56 -0600
              Re: Getting started with AVR and C glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-11-28 21:45 +0000
                Re: Getting started with AVR and C Tim Wescott <tim@seemywebsite.com> - 2012-11-28 15:55 -0600
                Re: Getting started with AVR and C David Brown <david.brown@removethis.hesbynett.no> - 2012-11-29 01:35 +0100
                Re: Getting started with AVR and C Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2012-11-29 01:47 +0100
                Re: Getting started with AVR and C David Brown <david@westcontrol.removethisbit.com> - 2012-11-29 09:24 +0100
                Re: Getting started with AVR and C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-11-29 01:18 +0000
                Re: Getting started with AVR and C Tim Wescott <tim@seemywebsite.com> - 2012-11-28 20:07 -0600
                Re: Getting started with AVR and C Grant Edwards <invalid@invalid.invalid> - 2012-11-29 15:23 +0000
                Re: Getting started with AVR and C James Kuyper <jameskuyper@verizon.net> - 2012-11-29 11:01 -0500
                Re: Getting started with AVR and C Grant Edwards <invalid@invalid.invalid> - 2012-11-29 19:19 +0000
                Re: Getting started with AVR and C James Kuyper <jameskuyper@verizon.net> - 2012-11-29 14:32 -0500
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-11-29 11:44 -0800
                Re: Getting started with AVR and C glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-11-29 21:23 +0000
                Re: Getting started with AVR and C Keith Thompson <kst-u@mib.org> - 2012-11-29 18:15 -0800
                Re: Getting started with AVR and C me@linnix.info-for.us - 2012-11-30 09:26 -0800
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-11-30 13:22 -0800
                Re: Getting started with AVR and C me@linnix.info-for.us - 2012-11-30 14:10 -0800
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-11-30 15:16 -0800
                Re: Getting started with AVR and C Mel Wilson <mwilson@the-wire.com> - 2012-11-30 17:36 -0500
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-11-30 15:18 -0800
                Re: Getting started with AVR and C upsidedown@downunder.com - 2012-12-01 10:08 +0200
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-12-01 00:45 -0800
                Re: Getting started with AVR and C Ed Beroset <beroset@mindspring.com> - 2012-12-01 08:00 -0500
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-12-01 13:22 -0800
                Re: Getting started with AVR and C Mark Borgerson <mborgerson@comcast.net> - 2012-12-01 17:33 -0800
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-12-01 17:43 -0800
                Re: Getting started with AVR and C Mark Borgerson <mborgerson@comcast.net> - 2012-12-02 14:13 -0800
                Re: Getting started with AVR and C Walter Banks <walter@bytecraft.com> - 2012-12-04 20:34 -0500
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-12-04 18:25 -0800
                Re: Getting started with AVR and C Walter Banks <walter@bytecraft.com> - 2012-12-05 07:55 -0500
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-12-05 12:11 -0800
                Re: Getting started with AVR and C Mark Borgerson <mborgerson@comcast.net> - 2012-12-05 07:52 -0800
                Re: Getting started with AVR and C Walter Banks <walter@bytecraft.com> - 2012-12-05 11:02 -0500
                Re: Getting started with AVR and C upsidedown@downunder.com - 2012-12-05 21:28 +0200
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-12-05 12:21 -0800
                Re: Getting started with AVR and C upsidedown@downunder.com - 2012-12-05 23:05 +0200
                Re: Getting started with AVR and C Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2012-12-05 23:22 +0200
                Re: Getting started with AVR and C Niklas Holsti <niklas.holsti@tidorum.invalid> - 2012-12-06 00:00 +0200
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-12-05 12:17 -0800
                Re: Getting started with AVR and C upsidedown@downunder.com - 2012-12-05 23:10 +0200
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-12-05 15:25 -0800
                Re: Getting started with AVR and C upsidedown@downunder.com - 2012-12-06 07:15 +0200
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-12-05 21:52 -0800
                Re: Getting started with AVR and C Lanarcam <lanarcam1@yahoo.fr> - 2012-12-06 20:59 +0100
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-12-06 12:38 -0800
                Re: Getting started with AVR and C George Neuner <gneuner2@comcast.net> - 2012-12-06 20:39 -0500
                Re: Getting started with AVR and C Walter Banks <walter@bytecraft.com> - 2012-12-06 22:31 -0500
                Re: Getting started with AVR and C Mel Wilson <mwilson@the-wire.com> - 2012-12-05 16:32 -0500
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-12-05 15:25 -0800
                Re: Getting started with AVR and C dp <dp@tgi-sci.com> - 2012-12-05 17:04 -0800
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-12-05 22:01 -0800
                Re: Getting started with AVR and C Ian Malcolm <See.My.Sig.for.email@totally.invalid> - 2012-12-06 14:05 +0000
                Re: Getting started with AVR and C dp <dp@tgi-sci.com> - 2012-12-06 10:28 -0800
                Re: Getting started with AVR and C Mark Borgerson <mborgerson@comcast.net> - 2012-12-06 16:58 -0800
                Re: Getting started with AVR and C Mark Borgerson <mborgerson@comcast.net> - 2012-12-06 07:34 -0800
                Re: Getting started with AVR and C Walter Banks <walter@bytecraft.com> - 2012-12-06 10:55 -0500
                Re: Getting started with AVR and C Rich Webb <bbew.ar@mapson.nozirev.ten> - 2012-12-06 11:11 -0500
                Re: Getting started with AVR and C Rocky <RobertGush@gmail.com> - 2012-12-06 21:38 -0800
                Re: Getting started with AVR and C dp <dp@tgi-sci.com> - 2012-12-07 03:49 -0800
                Re: Getting started with AVR and C Robert Wessel <robertwessel2@yahoo.com> - 2012-12-01 02:58 -0600
                Re: Getting started with AVR and C upsidedown@downunder.com - 2012-12-01 17:28 +0200
                Re: Getting started with AVR and C Robert Wessel <robertwessel2@yahoo.com> - 2012-12-01 11:55 -0600
                Re: Getting started with AVR and C upsidedown@downunder.com - 2012-11-29 22:17 +0200
                Re: Getting started with AVR and C Keith Thompson <kst-u@mib.org> - 2012-11-29 12:36 -0800
                Re: Getting started with AVR and C Stephen Sprunk <stephen@sprunk.org> - 2012-11-29 16:22 -0600
                Re: Getting started with AVR and C Keith Thompson <kst-u@mib.org> - 2012-11-29 18:36 -0800
                Re: Getting started with AVR and C "Boudewijn Dijkstra" <sp4mtr4p.boudewijn@indes.com> - 2012-12-11 10:53 +0100
                Re: Getting started with AVR and C John Devereux <john@devereux.me.uk> - 2012-12-11 14:53 +0000
                Unicode Ivan Shmakov <oneingray@gmail.com> - 2012-12-14 23:25 +0700
                Re: Getting started with AVR and C Richard Damon <news.x.richarddamon@xoxy.net> - 2012-12-15 14:30 -0500
                Re: Getting started with AVR and C Keith Thompson <kst-u@mib.org> - 2012-12-15 12:24 -0800
                Re: Getting started with AVR and C Richard Damon <news.x.richarddamon@xoxy.net> - 2012-12-15 18:02 -0500
                Re: Getting started with AVR and C Keith Thompson <kst-u@mib.org> - 2012-12-15 15:45 -0800
                Re: Getting started with AVR and C Richard Damon <news.x.richarddamon@xoxy.net> - 2012-12-16 22:55 -0500
                Re: Getting started with AVR and C Keith Thompson <kst-u@mib.org> - 2012-12-16 23:20 -0800
                Re: Getting started with AVR and C Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-12-17 12:27 +0200
                Re: Getting started with AVR and C John Devereux <john@devereux.me.uk> - 2012-12-17 11:17 +0000
                Re: Getting started with AVR and C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-17 14:07 +0000
                Re: Getting started with AVR and C Nobody <nobody@nowhere.com> - 2012-12-16 03:28 +0000
                Re: Getting started with AVR and C upsidedown@downunder.com - 2012-12-16 10:40 +0200
                Re: Getting started with AVR and C glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-11-29 02:31 +0000
                Re: Getting started with AVR and C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-11-29 03:36 +0000
                Re: Getting started with AVR and C glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-11-29 03:55 +0000
                Re: Getting started with AVR and C Christopher Head <chead@is.invalid> - 2012-11-28 23:24 -0800
                Re: Getting started with AVR and C David Brown <david@westcontrol.removethisbit.com> - 2012-11-29 09:37 +0100
                Re: Getting started with AVR and C glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-11-29 11:31 +0000
                Re: Getting started with AVR and C David Brown <david@westcontrol.removethisbit.com> - 2012-11-29 13:44 +0100
                Re: Getting started with AVR and C Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2012-11-29 13:22 +0100
                Re: Getting started with AVR and C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-11-29 13:32 +0000
                Re: Getting started with AVR and C Keith Thompson <kst-u@mib.org> - 2012-11-29 11:28 -0800
                Re: Getting started with AVR and C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-11-29 13:20 +0000
                Re: Getting started with AVR and C James Kuyper <jameskuyper@verizon.net> - 2012-11-29 09:07 -0500
                Re: Getting started with AVR and C James Kuyper <jameskuyper@verizon.net> - 2012-11-29 09:17 -0500
                Re: Getting started with AVR and C pete <pfiland@mindspring.com> - 2012-11-29 18:25 -0500
                Re: Getting started with AVR and C James Kuyper <jameskuyper@verizon.net> - 2012-11-29 22:46 -0500
                Re: Getting started with AVR and C lawrence.jones@siemens.com - 2012-11-30 11:47 -0500
                Re: Getting started with AVR and C Keith Thompson <kst-u@mib.org> - 2012-11-29 11:38 -0800
                Re: Getting started with AVR and C James Kuyper <jameskuyper@verizon.net> - 2012-11-29 15:21 -0500
              Re: Getting started with AVR and C Grant Edwards <invalid@invalid.invalid> - 2012-11-28 22:26 +0000
                Re: Getting started with AVR and C Tim Wescott <tim@seemywebsite.com> - 2012-11-28 17:32 -0600
                Re: Getting started with AVR and C James Kuyper <jameskuyper@verizon.net> - 2012-11-28 19:02 -0500
                Re: Getting started with AVR and C Tim Wescott <tim@seemywebsite.com> - 2012-11-28 18:29 -0600
                Re: Getting started with AVR and C James Kuyper <jameskuyper@verizon.net> - 2012-11-28 23:39 -0500
                Re: Getting started with AVR and C Tim Wescott <tim@seemywebsite.please> - 2012-11-29 00:59 -0600
                Re: Getting started with AVR and C James Kuyper <jameskuyper@verizon.net> - 2012-11-29 07:57 -0500
                Re: Getting started with AVR and C Tim Wescott <tim@seemywebsite.com> - 2012-11-29 13:02 -0600
                Re: Getting started with AVR and C Grant Edwards <invalid@invalid.invalid> - 2012-11-29 15:19 +0000
                Re: Getting started with AVR and C Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-11-29 12:03 +0200
                Re: Getting started with AVR and C glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-11-29 11:39 +0000
                Re: Getting started with AVR and C James Kuyper <jameskuyper@verizon.net> - 2012-11-29 08:04 -0500
                Re: Getting started with AVR and C Grant Edwards <invalid@invalid.invalid> - 2012-11-29 15:17 +0000
              Re: Getting started with AVR and C Tim Wescott <tim@seemywebsite.com> - 2012-11-28 19:19 -0600
                Re: Getting started with AVR and C James Kuyper <jameskuyper@verizon.net> - 2012-11-28 23:44 -0500
          Re: Getting started with AVR and C James Kuyper <jameskuyper@verizon.net> - 2012-11-28 13:15 -0500
            Re: Getting started with AVR and C Arlet Ottens <usenet+5@c-scape.nl> - 2012-11-28 19:17 +0100
              Re: Getting started with AVR and C Tim Wescott <tim@seemywebsite.com> - 2012-11-28 19:30 -0600
                Re: Getting started with AVR and C Grant Edwards <invalid@invalid.invalid> - 2012-11-29 15:29 +0000
                Re: Getting started with AVR and C John Devereux <john@devereux.me.uk> - 2012-11-29 16:36 +0000
                Re: Getting started with AVR and C upsidedown@downunder.com - 2012-11-29 22:40 +0200
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-11-29 13:55 -0800
                Re: Getting started with AVR and C Grant Edwards <invalid@invalid.invalid> - 2012-11-29 22:06 +0000
                Re: Getting started with AVR and C Jon Kirwan <jonk@infinitefactors.org> - 2012-11-29 14:22 -0800
                Re: Getting started with AVR and C Grant Edwards <invalid@invalid.invalid> - 2012-11-29 21:59 +0000
                Re: Getting started with AVR and C John Devereux <john@devereux.me.uk> - 2012-11-30 08:29 +0000
    Re: Getting started with AVR and C Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-11-25 05:41 -0800
    Re: Getting started with AVR and C Rosario1903 <Rosario@invalid.invalid> - 2012-11-27 10:21 +0100
  Re: Getting started with AVR and C dbr@kbrx.com - 2012-11-24 21:49 +0000
    Re: Getting started with AVR and C MK <mk@nospam.co.uk> - 2012-11-25 12:24 +0000
      Re: Getting started with AVR and C Ian Malcolm <See.My.Sig.for.email@totally.invalid> - 2012-11-26 00:08 +0000

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