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Groups > comp.lang.c > #78096

Re: Right C version for GCC

From David Brown <david.brown@hesbynett.no>
Newsgroups comp.lang.c
Subject Re: Right C version for GCC
Date 2015-12-07 17:30 +0100
Organization A noiseless patient Spider
Message-ID <n44c3c$9lp$1@dont-email.me> (permalink)
References (9 earlier) <s4c86bhebtgjcs5udkhrlnc85aqeli6v4v@4ax.com> <n429fq$b5s$1@dont-email.me> <slrnn69ed2.5q5.grahn+nntp@frailea.sa.invalid> <n43gv9$1ga$1@dont-email.me> <ebb1b3a4-359f-4a17-a91e-a6f0470c4041@googlegroups.com>

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On 07/12/15 16:30, supercat@casperkitty.com wrote:
> On Monday, December 7, 2015 at 2:48:03 AM UTC-6, David Brown wrote:
>> On the other hand, this means that if you have a large bss section, the
>> chip's watchdog can reset the chip before main() has started and you can
>> easily kick the dog (or disable it).  I cannot fathom why anyone would
>> make watchdog hardware enabled out of reset - that's a design flaw in
>> the hardware.
> 
> I would have said the opposite--watchdogs should be enabled out of reset
> unless code explicitly disables them.  Otherwise a bodged reset could
> leave the chip in a random-code-execution state with watchdog disabled,
> though a good design should provide options of making the watchdog enable
> state permanent until the next reset, the next power-off, or until the
> next time code wants to change it, rather than forcing code to commit to
> one particular pattern.

If there is a chance that your reset (hardware) could be botched, your
hardware is broken and the watchdog will not fix it.  At best, it will
hide the problem.

If there is a chance that your reset software handling could be botched,
your software is broken and the watchdog will not fix it.  At best, it
will hide the problem.

Watchdogs can be a useful guard against very rare hardware events, such
as cosmic rays or unexpected hardware glitches.  Even then, they are
seldom particularly helpful, because most such glitches will not cause a
normal, safely operating system to enter a state where it is still
operating safely (noting that "completely stopped" may be considered a
safe operating condition) but the watchdog is no longer being regularly
kicked.

I have heard the description of a watchdog as being akin to hitting a
dead man repeatedly over the head with a hammer, in the hope that /this/
time he wakes up.

I certainly cannot think of a single occasion in which I know a system
has been restarted by a watchdog, in which there was not a serious
underlying bug in the hardware or software which should have been fixed.
 And I can think of a great many occasions in which unexpected watchdog
timeouts have caused trouble.

If someone wants to use a watchdog on a chip, then they should be free
to enable it - but in the majority of my systems the first step of the
code is to disable the watchdog.

> 
>> (Technically, this is not a compiler issue but a library issue - it's
>> the library's C startup code that clears bss.  But to most users, it
>> appears as a compiler bug.)
> 
> The compiler and library form an "implementation".
> 

I am not sure that the startup code in the library is considered part of
the C implementation, it doesn't matter one way or the other.

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Thread

Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-08 16:49 +0100
  Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-08 19:29 +0100
  Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-08 11:46 -0800
    Re: Right C version for GCC Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-11-08 20:03 +0000
      Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-08 12:18 -0800
    Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-08 21:14 +0100
      Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-08 12:25 -0800
        Re: Right C version for GCC supercat@casperkitty.com - 2015-11-08 13:06 -0800
          Re: Right C version for GCC Philip Lantz <prl@canterey.us> - 2015-11-08 14:52 -0800
            Re: Right C version for GCC supercat@casperkitty.com - 2015-11-08 15:12 -0800
              Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-09 09:38 +0100
              Re: Right C version for GCC Nick Bowler <nbowler@draconx.ca> - 2015-11-09 19:04 +0000
                Re: Right C version for GCC supercat@casperkitty.com - 2015-11-09 11:27 -0800
            Re: Right C version for GCC BartC <bc@freeuk.com> - 2015-11-09 00:00 +0000
        Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-08 16:35 -0800
    Re: Right C version for GCC supercat@casperkitty.com - 2015-11-08 12:37 -0800
      Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-08 12:58 -0800
        Re: Right C version for GCC supercat@casperkitty.com - 2015-11-08 13:19 -0800
    Re: Right C version for GCC Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-08 21:49 +0000
      Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-08 14:14 -0800
        Re: Right C version for GCC Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-09 01:02 +0000
          Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-09 02:26 -0800
            Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-09 12:53 +0100
            Re: Right C version for GCC Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-09 15:00 +0000
              Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-09 08:55 -0800
                Re: Right C version for GCC Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-09 17:07 +0000
                Re: Right C version for GCC supercat@casperkitty.com - 2015-11-09 09:51 -0800
                Re: Right C version for GCC jacobnavia <jacob@jacob.remcomp.fr> - 2015-11-09 19:01 +0100
                Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-09 19:16 +0100
                Re: Right C version for GCC supercat@casperkitty.com - 2015-11-09 11:24 -0800
                Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-09 20:30 +0100
                Re: Right C version for GCC jacobnavia <jacob@jacob.remcomp.fr> - 2015-11-09 20:40 +0100
            Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-09 08:56 -0800
              Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-09 09:41 -0800
                Re: Right C version for GCC gazelle@shell.xmission.com (Kenny McCormack) - 2015-11-09 17:44 +0000
                Re: Right C version for GCC Philipp Klaus Krause <pkk@spth.de> - 2015-11-09 18:53 +0100
                Re: Right C version for GCC Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-09 18:00 +0000
                Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-09 10:27 -0800
                Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-09 11:17 -0800
                Re: Right C version for GCC glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-11-09 22:59 +0000
                Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-09 11:15 -0800
                Re: Right C version for GCC Philipp Klaus Krause <pkk@spth.de> - 2015-11-12 16:47 +0100
                Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-12 09:24 -0800
                Re: Right C version for GCC Philipp Klaus Krause <pkk@spth.de> - 2015-11-13 12:54 +0100
                Re: Right C version for GCC Tim Rentsch <txr@alumni.caltech.edu> - 2015-11-13 12:01 -0800
                Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-14 10:47 -0800
                Re: Right C version for GCC Philipp Klaus Krause <pkk@spth.de> - 2015-11-14 21:32 +0100
                Re: Right C version for GCC Tim Rentsch <txr@alumni.caltech.edu> - 2015-11-14 16:57 -0800
                Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-09 11:07 -0800
                Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-09 20:18 +0100
                Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-09 11:27 -0800
                Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-09 20:41 +0100
                Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-09 12:07 -0800
                Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-09 21:12 +0100
                Re: Right C version for GCC glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-11-09 23:13 +0000
                Re: Right C version for GCC James Kuyper <jameskuyper@verizon.net> - 2015-11-09 19:02 -0500
                Re: Right C version for GCC raltbos@xs4all.nl (Richard Bos) - 2015-11-10 17:52 +0000
                Re: Right C version for GCC glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-11-10 21:34 +0000
                Re: Right C version for GCC raltbos@xs4all.nl (Richard Bos) - 2015-11-17 22:28 +0000
                Re: Right C version for GCC glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-11-18 00:51 +0000
                Re: Right C version for GCC James Kuyper <jameskuyper@verizon.net> - 2015-11-17 22:26 -0500
                Re: Right C version for GCC Philipp Klaus Krause <pkk@spth.de> - 2015-11-18 11:06 +0100
                Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-09 15:37 -0800
                Re: Right C version for GCC Ian Collins <ian-news@hotmail.com> - 2015-11-10 12:54 +1300
                Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-09 16:14 -0800
                Re: Right C version for GCC supercat@casperkitty.com - 2015-11-09 16:37 -0800
                Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-09 16:56 -0800
                Re: Right C version for GCC supercat@casperkitty.com - 2015-11-09 17:25 -0800
                Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-10 10:37 +0100
                Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-09 18:06 -0800
                Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-09 18:51 -0800
                Re: Right C version for GCC supercat@casperkitty.com - 2015-11-10 08:40 -0800
                Re: Right C version for GCC raltbos@xs4all.nl (Richard Bos) - 2015-11-10 17:55 +0000
                Re: Right C version for GCC raltbos@xs4all.nl (Richard Bos) - 2015-11-10 17:50 +0000
                Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-12 14:32 +0100
          Re: Right C version for GCC Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-11-09 10:35 +0000
      Re: Right C version for GCC Philipp Klaus Krause <pkk@spth.de> - 2015-11-08 23:57 +0100
        Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-09 00:47 +0100
          Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-09 13:01 +0100
            Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-09 13:18 +0100
              Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-09 14:01 +0100
        Re: Right C version for GCC Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-09 00:55 +0000
          Re: Right C version for GCC Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-11-09 10:42 +0000
            Re: Right C version for GCC Chad <cdalten@gmail.com> - 2015-11-09 03:03 -0800
              Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-09 03:27 -0800
                Re: Right C version for GCC BartC <bc@freeuk.com> - 2015-11-09 12:28 +0000
                Re: Right C version for GCC Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-11-10 09:07 +0000
              Re: Right C version for GCC James Kuyper <jameskuyper@verizon.net> - 2015-11-09 07:37 -0500
            Re: Right C version for GCC Philipp Klaus Krause <pkk@spth.de> - 2015-11-09 16:57 +0100
      Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-09 12:39 +0100
        Re: Right C version for GCC James Kuyper <jameskuyper@verizon.net> - 2015-11-09 13:18 -0500
          Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-10 10:49 +0100
            Re: Right C version for GCC Les Cargill <lcargill99@comcast.com> - 2015-11-10 19:33 -0600
              Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-11 13:34 +0100
                Re: Right C version for GCC supercat@casperkitty.com - 2015-11-11 06:53 -0800
    Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-08 17:00 -0800
      Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-09 13:37 +0100
      Re: Right C version for GCC Philipp Klaus Krause <pkk@spth.de> - 2015-11-09 13:53 +0100
    Re: Right C version for GCC BartC <bc@freeuk.com> - 2015-11-09 21:54 +0000
      Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-09 15:45 -0800
        Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-10 11:14 +0100
          Re: Right C version for GCC BartC <bc@freeuk.com> - 2015-11-10 10:53 +0000
          Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-10 03:14 -0800
            Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-10 13:00 +0100
              Re: Right C version for GCC BartC <bc@freeuk.com> - 2015-11-10 12:39 +0000
                Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-10 15:11 +0100
                Re: Right C version for GCC Philipp Klaus Krause <pkk@spth.de> - 2015-11-10 16:16 +0100
                Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-10 16:35 +0100
                Re: Right C version for GCC supercat@casperkitty.com - 2015-11-10 08:54 -0800
                Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-10 18:56 +0100
                Re: Right C version for GCC Philipp Klaus Krause <pkk@spth.de> - 2015-11-10 23:27 +0100
                Re: Right C version for GCC raltbos@xs4all.nl (Richard Bos) - 2015-11-17 22:32 +0000
                Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-18 08:44 +0100
                Re: Right C version for GCC raltbos@xs4all.nl (Richard Bos) - 2015-11-19 10:43 +0000
                Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-19 12:29 +0100
                Re: Right C version for GCC raltbos@xs4all.nl (Richard Bos) - 2015-11-20 11:01 +0000
                Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-21 15:50 +0100
                Re: Right C version for GCC Philipp Klaus Krause <pkk@spth.de> - 2015-11-18 11:13 +0100
              Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-10 07:25 -0800
                Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-10 16:42 +0100
                Re: Right C version for GCC supercat@casperkitty.com - 2015-11-10 08:48 -0800
                Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-11 01:08 -0800
                Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-11 13:43 +0100
                Re: Right C version for GCC Les Cargill <lcargill99@comcast.com> - 2015-11-11 08:27 -0600
                Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-11 16:27 +0100
                Re: Right C version for GCC David Thompson <dave.thompson2@verizon.net> - 2015-12-06 07:57 -0500
                Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-12-06 22:34 +0100
                Re: Right C version for GCC Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-12-06 22:41 +0000
                Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-12-07 09:47 +0100
                Re: Right C version for GCC supercat@casperkitty.com - 2015-12-07 07:30 -0800
                Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-12-07 17:30 +0100
                Re: Right C version for GCC supercat@casperkitty.com - 2015-12-07 10:17 -0800
                Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-12-07 21:29 +0100
                Re: Right C version for GCC supercat@casperkitty.com - 2015-12-07 13:16 -0800
                Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-12-07 23:35 +0100
                Re: Right C version for GCC jadill33@gmail.com - 2015-12-07 10:41 -0800
                Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-12-07 21:35 +0100
  Re: Right C version for GCC Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-11-08 20:11 +0000
  Re: Right C version for GCC Ian Collins <ian-news@hotmail.com> - 2015-11-09 09:57 +1300
    Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-08 13:06 -0800
      Re: Right C version for GCC Ian Collins <ian-news@hotmail.com> - 2015-11-09 10:16 +1300
        Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-08 22:59 +0100
          Re: Right C version for GCC Ian Collins <ian-news@hotmail.com> - 2015-11-09 12:13 +1300
            Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-09 00:43 +0100
              Re: Right C version for GCC Ian Collins <ian-news@hotmail.com> - 2015-11-09 13:00 +1300
                Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-09 12:02 +0100
                Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-09 09:00 -0800
                Re: Right C version for GCC Ian Collins <ian-news@hotmail.com> - 2015-11-10 07:25 +1300
                Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-09 19:35 +0100
                Re: Right C version for GCC Ian Collins <ian-news@hotmail.com> - 2015-11-10 08:55 +1300
                Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-09 21:00 +0100
                Re: Right C version for GCC Ian Collins <ian-news@hotmail.com> - 2015-11-10 09:04 +1300
                Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-09 21:11 +0100
                Re: Right C version for GCC Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-09 20:18 +0000
                Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-09 21:21 +0100
                Re: Right C version for GCC Ian Collins <ian-news@hotmail.com> - 2015-11-10 09:30 +1300
                Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-09 12:53 -0800
                Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-09 12:30 -0800
                Re: Right C version for GCC supercat@casperkitty.com - 2015-11-09 13:02 -0800
                Re: Right C version for GCC BartC <bc@freeuk.com> - 2015-11-09 21:35 +0000
                Re: Right C version for GCC supercat@casperkitty.com - 2015-11-09 14:41 -0800
                Re: Right C version for GCC BartC <bc@freeuk.com> - 2015-11-09 23:31 +0000
                Re: Right C version for GCC supercat@casperkitty.com - 2015-11-09 16:33 -0800
                Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-10 11:16 +0100
                Re: Right C version for GCC Ian Collins <ian-news@hotmail.com> - 2015-11-11 08:04 +1300
                Re: Right C version for GCC raltbos@xs4all.nl (Richard Bos) - 2015-11-10 18:04 +0000
                Re: Right C version for GCC raltbos@xs4all.nl (Richard Bos) - 2015-11-10 18:03 +0000
                Re: Right C version for GCC Ian Collins <ian-news@hotmail.com> - 2015-11-11 08:23 +1300
          Re: Right C version for GCC David Brown <david.brown@hesbynett.no> - 2015-11-09 13:41 +0100
      Re: Right C version for GCC supercat@casperkitty.com - 2015-11-08 13:24 -0800
      Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-08 23:00 +0100
        Re: Right C version for GCC Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-08 15:18 -0800
          Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-09 00:35 +0100
          Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-08 17:03 -0800
            Re: Right C version for GCC Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-11-09 12:42 +0000
  Re: Right C version for GCC Keith Thompson <kst-u@mib.org> - 2015-11-08 17:51 -0800
  Re: Right C version for GCC Les Cargill <lcargill99@comcast.com> - 2015-11-09 12:20 -0600
    Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-09 19:36 +0100
    Re: Right C version for GCC BartC <bc@freeuk.com> - 2015-11-09 18:47 +0000
  Re: Right C version for GCC Stephen Sprunk <stephen@sprunk.org> - 2015-11-11 00:55 -0600
    Re: Right C version for GCC "Morten W. Petersen" <morphex@gmail.com> - 2015-11-12 14:39 +0100

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