Re: Exception propagation in C

From	jacob navia <jacob@spamsink.net>
Newsgroups	comp.lang.c, alt.os.development
Subject	Re: Exception propagation in C
Date	2012-01-09 00:19 +0100
Organization	lccwin
Message-ID	<jed8aa$npp$1@speranza.aioe.org> (permalink)
References	(4 earlier) <98257b01-551a-48fe-8474-0e7df1988aa7@f11g2000yql.googlegroups.com> <jdvn0l$bet$1@news.albasani.net> <5b3c65a3-ccf7-40ce-a161-55e106a93c44@w4g2000vbc.googlegroups.com> <je7k70$3nf$1@news.albasani.net> <8d5062d8-9470-4383-8427-26563c7cac7a@m20g2000vbf.googlegroups.com>

Cross-posted to 2 groups.

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Le 08/01/12 23:20, James Harris a écrit :
>
> As mentioned, it's the other way round. Each task needs access to a
> machine word that belongs to the kernel. I can't see anything special
> being needed. Am I missing something?

Yes, you are missing everything:

1) Many people including me have told you that each thread needs an
    exception handler, in a multi-threaded environment. It can't be
    just a machine word somewhere. It must be thread local storage

2) Accessing that machine word by polling, as you propose can't be done
    in one instruction since you need the thread ID to be able to access
    the thread local storage.

3) You need exclusive access to that machine word. You do not want other
    process to write to it when you are reading. Remember that today's
    CPUs have several cores. Having a thread gain exclusive access would
    BLOCK all other threads since they are constantly polling that
    famous machine word... If a thread gains exclusive access to that
    address and then dies without releasing the lock the PROCESS STOPS.
    All threads are blocked.

I could go on but what would be the point?

Can you explain why the existing schemas that have been developed
through many years of usage and debugging do not please you?

Why do you feel compelled to reinvent the wheel by proposing a
square wheel?

HINT: Wheels should be round :-)

HINT: Exception handlers are invoked by the OS or a throw in a given
       thread and walk the stack seeking a handler using the tables
       generated by the compiler

Thread

Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2011-12-29 09:52 -0800
  Re: Exception propagation in C jacob navia <jacob@spamsink.net> - 2011-12-29 19:40 +0100
    Re: Exception propagation in C BGB <cr88192@hotmail.com> - 2011-12-29 14:03 -0600
  Re: Exception propagation in C BGB <cr88192@hotmail.com> - 2011-12-29 13:07 -0600
    Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2011-12-30 13:38 -0800
      Re: Exception propagation in C BGB <cr88192@hotmail.com> - 2011-12-30 20:24 -0600
        Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2012-01-03 02:19 -0800
          Re: Exception propagation in C BGB <cr88192@hotmail.com> - 2012-01-03 14:04 -0600
            Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2012-01-04 04:26 -0800
              Re: Exception propagation in C BGB <cr88192@hotmail.com> - 2012-01-06 14:05 -0600
                Re: Exception propagation in C jacob navia <jacob@spamsink.net> - 2012-01-06 23:54 +0100
                Re: Exception propagation in C "Ed Coran" <sysdev@new.net> - 2012-01-06 22:24 -0600
                Re: Exception propagation in C jacob navia <jacob@spamsink.net> - 2012-01-07 09:15 +0100
                Re: Exception propagation in C "Ed Coran" <sysdev@new.net> - 2012-01-08 23:45 -0600
                Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2012-01-08 12:52 -0800
                Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2012-01-08 14:20 -0800
                Re: Exception propagation in C jacob navia <jacob@spamsink.net> - 2012-01-09 00:19 +0100
                Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2012-01-08 21:12 -0800
                Re: Exception propagation in C Scott Wood <scott@buserror.net> - 2012-01-08 23:41 -0600
                Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2012-01-09 11:00 -0800
                Re: Exception propagation in C Scott Wood <scott@buserror.net> - 2012-01-10 00:42 -0600
                Re: Exception propagation in C jgk@panix.com (Joe keane) - 2012-01-11 07:40 +0000
                Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2012-01-11 12:59 -0800
                Re: Exception propagation in C "Ed Coran" <sysdev@new.net> - 2012-01-09 00:05 -0600
                Re: Exception propagation in C Ian Collins <ian-news@hotmail.com> - 2012-01-09 20:40 +1300
                Re: Exception propagation in C "Ed Coran" <sysdev@new.net> - 2012-01-09 04:53 -0600
                Re: Exception propagation in C 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-09 05:49 -0800
                Re: Exception propagation in C Scott Wood <scott@buserror.net> - 2012-01-08 17:29 -0600
                Re: Exception propagation in C jacob navia <jacob@spamsink.net> - 2012-01-09 00:37 +0100
                Re: Exception propagation in C Nomen Nescio <nobody@dizum.com> - 2012-01-09 11:36 +0100
                Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2012-01-09 11:08 -0800
          Re: Exception propagation in C Scott Wood <scott@buserror.net> - 2012-01-05 01:25 -0600
            Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2012-01-05 09:18 -0800
      Re: Exception propagation in C "s_dubrovich@yahoo.com" <s_dubrovich@yahoo.com> - 2011-12-30 21:20 -0800
        Re: Exception propagation in C "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2011-12-31 06:19 -0500
        Re: Exception propagation in C Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-01-01 10:32 -0800
      Re: Exception propagation in C "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2011-12-31 05:53 -0500
        Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2012-01-01 16:30 -0800
          Re: Exception propagation in C "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-01-02 01:50 -0500
            Re: Exception propagation in C Scott Wood <scott@buserror.net> - 2012-01-02 02:03 -0600
              Re: Exception propagation in C "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-01-02 15:59 -0500
                Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2012-01-03 04:12 -0800
                Re: Exception propagation in C Scott Wood <scott@buserror.net> - 2012-01-04 23:53 -0600
                Re: Exception propagation in C "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-01-05 06:45 -0500
            Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2012-01-03 04:16 -0800
              Re: Exception propagation in C Keith Thompson <kst-u@mib.org> - 2012-01-03 11:50 -0800
      Re: Exception propagation in C Jens Gustedt <jens.gustedt@loria.fr> - 2011-12-31 13:40 +0100
        Re: Exception propagation in C BGB <cr88192@hotmail.com> - 2011-12-31 10:40 -0600
          Re: Exception propagation in C Jens Gustedt <jens.gustedt@loria.fr> - 2012-01-02 16:49 +0100
            Re: Exception propagation in C BGB <cr88192@hotmail.com> - 2012-01-02 13:02 -0600
              Re: Exception propagation in C Dr Nick <3-nospam@temporary-address.org.uk> - 2012-01-02 19:53 +0000
                Re: Exception propagation in C ImpalerCore <jadill33@gmail.com> - 2012-01-02 13:10 -0800
              Re: Exception propagation in C ImpalerCore <jadill33@gmail.com> - 2012-01-02 12:58 -0800
              Re: Exception propagation in C Jens Gustedt <jens.gustedt@loria.fr> - 2012-01-04 18:01 +0100
                Re: Exception propagation in C BGB <cr88192@hotmail.com> - 2012-01-06 14:38 -0600
                Re: Exception propagation in C "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-01-06 21:40 -0500
  Re: Exception propagation in C Kaz Kylheku <kaz@kylheku.com> - 2011-12-29 21:02 +0000
    Re: Exception propagation in C jacob navia <jacob@spamsink.net> - 2011-12-30 10:38 +0100
    Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2011-12-30 14:38 -0800
  Re: Exception propagation in C "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2011-12-29 18:37 -0500
  Re: Exception propagation in C "BartC" <bc@freeuk.com> - 2011-12-30 01:07 +0000
    Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2011-12-30 14:07 -0800
  Re: Exception propagation in C Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-30 17:53 -0500
    Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2012-01-03 03:56 -0800
  Re: Exception propagation in C jgk@panix.com (Joe keane) - 2012-01-02 09:49 +0000
    Re: Exception propagation in C Kleuske <kleuske@nowhere.net> - 2012-01-02 10:51 +0000
      Re: Exception propagation in C "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-01-02 16:01 -0500
        Re: Exception propagation in C Kleuske <kleuske@nowhere.net> - 2012-01-03 11:14 +0000
      Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2012-01-03 03:59 -0800
        Re: Exception propagation in C Kleuske <kleuske@nowhere.net> - 2012-01-03 12:09 +0000
  Re: Exception propagation in C jgk@panix.com (Joe keane) - 2012-01-03 21:25 +0000
    Re: Exception propagation in C James Harris <james.harris.1@googlemail.com> - 2012-02-15 14:24 -0800
      Re: Exception propagation in C jgk@panix.com (Joe keane) - 2012-02-17 22:38 +0000

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