Re: Testing if a pointer is valid

From	jacob navia <jacob@spamsink.net>
Newsgroups	comp.lang.c
Subject	Re: Testing if a pointer is valid
Date	2011-09-19 16:10 +0200
Organization	lccwin
Message-ID	<j57ihc$lv7$1@speranza.aioe.org> (permalink)
References	(10 earlier) <4e76baf8.298487352@text.giganews.com> <878vplxhln.fsf@blp.benpfaff.org> <4e76d2e5.304613339@text.giganews.com> <j56q4f$ljc$1@speranza.aioe.org> <0.7da8fa584f374ad88928.20110919142408BST.87d3ewvf5z.fsf@bsb.me.uk>

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Le 19/09/11 15:24, Ben Bacarisse a écrit :
> jacob navia<jacob@spamsink.net>  writes:
>
>> Le 19/09/11 07:38, Richard Harter a écrit :
>>>
>>> Fair enough, if those are your only choices.  Quite often, however,
>>> the cost of verification is insignificant.
>>
>> Exactly
>>
>>   Choosing the *fast*
>>> library could be a premature optimization.  Now if I actually had two
>>> libraries that did the same thing *and* I was really really concerned
>>> with speed *and* I did performance measurements on both *and* there a
>>> measurable difference, then I might go with the one that doesn't
>>> verify its inputs.  How often does that happen?
>>>
>>
>> Suppose you mark your data with a 64 bit magic number at the start
>> of the data structure.
>>
>> To know if you have a valid pointer you test its validity for
>> reading 64 bits (8 bytes). If the pointer is valid it takes you
>> several assignments, 2 calls to signal and 1 call to setjmp.
>>
>> You can fuse the testing for reading with the reading of the
>> magic number, so, in fact I would say that at most you are spending
>> several hundred cycles in testing pointer validty, what in
>> modern machines is nothing.
>>
>> If your magic numbers are cleverly built, you can also prevent
>> the much more common error of passing a valid pointer to a
>> DIFFERENT kind of object. For instance when writing the serializing
>> part of the container library I write a GUUID (128 bytes) of
>> magic number, what allows me to avoid trying to restore a list
>> container from a file that was actually a saved file from the
>> vector container!
>
> If it was a really clever scheme you'd have run-time type checking.

Well, that is run time type checking obviously. But ONLY when you want
and where you want, not everywhere.

> If
> the language were really clever, you could do this checking at compile
> time.

In most cases this is done in C. In most cases this checking is
unnecessary. But for life critical applications it could be worth
to spend some cycles avoiding crashing you see?

> It's one reason people choose to program in other languages.

Look, there are NO languages that will eliminate bugs. There is NO
silver bullet here.

   I
> am not entirely sure why all the people who program in C do so, but some
> do so because they want minimal run-time overhead

Exactly, and the run time overhead of a few pointer verifications at
a critical interface do not change that C is very fast anyway.

> so the case for doing
> what amounts to some limited run-time type-checking in C is not clear to
> me.

There could be a few applications, specially when debugging.

> There are languages that do it better, both at compile time and at
> run time.

No. I think C is quite good.

> I think you might be aiming at a niche market.
>
> <snip>

I am not "aiming" at any market. I am just discussing a function for
checking pointers if needed. I am not selling anything either. We are
so swamped by marketing that in a simple conversation about pointer
checking we need to do a market research first!

Please Ben, let's keep the discussion sane. I proposed a function for
pointer checking in its own rights, because I was surprised that it
could be so simple. Now, is it the panacea for avoiding bugs?

Surely not.

Thread

Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-18 00:29 +0200
  Re: Testing if a pointer is valid Harald van Dĳk <truedfx@gmail.com> - 2011-09-17 15:38 -0700
    Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-18 00:57 +0200
      Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-18 16:30 +0000
        Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-18 19:25 +0200
          Re: Testing if a pointer is valid Ian Collins <ian-news@hotmail.com> - 2011-09-19 07:53 +1200
          Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-18 20:00 +0000
            Re: Testing if a pointer is valid Ian Collins <ian-news@hotmail.com> - 2011-09-19 08:23 +1200
              Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-18 20:32 +0000
                Re: Testing if a pointer is valid cri@tiac.net (Richard Harter) - 2011-09-18 23:28 +0000
                Re: Testing if a pointer is valid blp@cs.stanford.edu (Ben Pfaff) - 2011-09-18 16:38 -0700
                Re: Testing if a pointer is valid cri@tiac.net (Richard Harter) - 2011-09-19 04:27 +0000
                Re: Testing if a pointer is valid blp@cs.stanford.edu (Ben Pfaff) - 2011-09-18 21:48 -0700
                Re: Testing if a pointer is valid cri@tiac.net (Richard Harter) - 2011-09-19 05:38 +0000
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-19 09:14 +0200
                Re: Testing if a pointer is valid "BartC" <bc@freeuk.com> - 2011-09-19 10:10 +0100
                Re: Testing if a pointer is valid Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-09-19 05:07 -0700
                Re: Testing if a pointer is valid Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-19 14:24 +0100
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-19 16:10 +0200
                Re: Testing if a pointer is valid "BartC" <bc@freeuk.com> - 2011-09-19 16:50 +0100
                Re: Testing if a pointer is valid Ben Pfaff <blp@cs.stanford.edu> - 2011-09-19 08:11 -0700
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-19 17:21 +0200
                Re: Testing if a pointer is valid "BartC" <bc@freeuk.com> - 2011-09-19 16:27 +0100
                Re: Testing if a pointer is valid Keith Thompson <kst-u@mib.org> - 2011-09-19 10:14 -0700
                Re: Testing if a pointer is valid "BartC" <bc@freeuk.com> - 2011-09-19 19:56 +0100
                Re: Testing if a pointer is valid blp@cs.stanford.edu (Ben Pfaff) - 2011-09-19 13:20 -0700
                Re: Testing if a pointer is valid Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-09-20 18:31 +0300
                Re: Testing if a pointer is valid "BartC" <bc@freeuk.com> - 2011-09-20 17:44 +0100
                Re: Testing if a pointer is valid Keith Thompson <kst-u@mib.org> - 2011-09-20 17:06 -0700
                Re: Testing if a pointer is valid "BartC" <bc@freeuk.com> - 2011-09-21 01:37 +0100
                Re: Testing if a pointer is valid Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-09-22 22:03 +0300
                Re: Testing if a pointer is valid Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-09-28 02:33 -0700
                Re: Testing if a pointer is valid ImpalerCore <jadill33@gmail.com> - 2011-09-19 13:01 -0700
                Re: Testing if a pointer is valid ImpalerCore <jadill33@gmail.com> - 2011-09-19 14:42 -0700
                Re: Testing if a pointer is valid Ian Collins <ian-news@hotmail.com> - 2011-09-20 10:08 +1200
                Re: Testing if a pointer is valid ImpalerCore <jadill33@gmail.com> - 2011-09-20 07:55 -0700
                Re: Testing if a pointer is valid cri@tiac.net (Richard Harter) - 2011-09-19 16:39 +0000
                Re: Testing if a pointer is valid blp@cs.stanford.edu (Ben Pfaff) - 2011-09-19 09:48 -0700
                Re: Testing if a pointer is valid ImpalerCore <jadill33@gmail.com> - 2011-09-19 12:49 -0700
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-19 22:45 +0200
                Re: Testing if a pointer is valid ImpalerCore <jadill33@gmail.com> - 2011-09-19 14:02 -0700
                Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-19 07:14 +0000
                Re: Testing if a pointer is valid cri@tiac.net (Richard Harter) - 2011-09-19 16:13 +0000
                Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-19 17:36 +0000
                Re: Testing if a pointer is valid cri@tiac.net (Richard Harter) - 2011-09-19 20:09 +0000
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-19 20:36 +0200
                Re: Testing if a pointer is valid Ian Collins <ian-news@hotmail.com> - 2011-09-20 08:05 +1200
                Re: Testing if a pointer is valid cri@tiac.net (Richard Harter) - 2011-09-19 20:18 +0000
                Re: Testing if a pointer is valid Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-09-19 23:37 +0000
                Re: Testing if a pointer is valid Kenneth Brody <kenbrody@spamcop.net> - 2011-09-21 12:23 -0400
                Re: Testing if a pointer is valid Kenneth Brody <kenbrody@spamcop.net> - 2011-09-21 12:09 -0400
                Re: Testing if a pointer is valid websnarf <websnarf@gmail.com> - 2011-09-26 22:01 -0700
                Re: Testing if a pointer is valid Kenneth Brody <kenbrody@spamcop.net> - 2011-09-19 13:51 -0400
                Re: Testing if a pointer is valid cri@tiac.net (Richard Harter) - 2011-09-19 20:11 +0000
                Re: Testing if a pointer is valid Nobody <nobody@nowhere.com> - 2011-09-19 22:21 +0100
                Re: Testing if a pointer is valid cri@tiac.net (Richard Harter) - 2011-09-20 00:05 +0000
          Re: Testing if a pointer is valid Nobody <nobody@nowhere.com> - 2011-09-18 23:34 +0100
          Re: Testing if a pointer is valid pacman@kosh.dhis.org (Alan Curry) - 2011-09-18 22:47 +0000
          Re: Testing if a pointer is valid tom st denis <tom@iahu.ca> - 2011-09-19 04:50 -0700
          Re: Testing if a pointer is valid Kenneth Brody <kenbrody@spamcop.net> - 2011-09-19 13:42 -0400
            Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-19 20:30 +0200
              Re: Testing if a pointer is valid Ian Collins <ian-news@hotmail.com> - 2011-09-20 08:09 +1200
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-19 22:38 +0200
                Re: Testing if a pointer is valid Ike Naar <ike@iceland.freeshell.org> - 2011-09-19 20:50 +0000
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-19 22:53 +0200
                Re: Testing if a pointer is valid Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-19 22:30 +0100
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-20 00:05 +0200
                Re: Testing if a pointer is valid Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-20 00:31 +0100
                Re: Testing if a pointer is valid Ike Naar <ike@iceland.freeshell.org> - 2011-09-19 22:43 +0000
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-20 00:59 +0200
                Re: Testing if a pointer is valid Ian Collins <ian-news@hotmail.com> - 2011-09-20 11:50 +1200
                Re: Testing if a pointer is valid blp@cs.stanford.edu (Ben Pfaff) - 2011-09-19 19:03 -0700
                Re: Testing if a pointer is valid Ian Collins <ian-news@hotmail.com> - 2011-09-20 14:11 +1200
                Re: Testing if a pointer is valid Keith Thompson <kst-u@mib.org> - 2011-09-19 21:49 -0700
                Re: Testing if a pointer is valid Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-09-28 06:17 -0700
                Re: Testing if a pointer is valid Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-09-28 07:02 -0700
                Re: Testing if a pointer is valid Ike Naar <ike@sverige.freeshell.org> - 2011-09-20 07:26 +0000
                Re: Testing if a pointer is valid Kenneth Brody <kenbrody@spamcop.net> - 2011-09-21 12:31 -0400
                Re: Testing if a pointer is valid Kenneth Brody <kenbrody@spamcop.net> - 2011-09-21 12:26 -0400
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-21 21:20 +0200
                Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-21 19:40 +0000
                Re: Testing if a pointer is valid Ian Collins <ian-news@hotmail.com> - 2011-09-22 07:46 +1200
                Re: Testing if a pointer is valid "Rosario Pulvirenti" <NoInUseno1Spam@non.usare.invalid> - 2011-09-22 07:38 +0200
                Re: Testing if a pointer is valid Ian Collins <ian-news@hotmail.com> - 2011-09-20 09:05 +1200
              Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-20 07:16 +0000
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-20 09:50 +0200
                Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-20 10:38 +0000
                Re: Testing if a pointer is valid Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-09-20 04:29 -0700
                Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-20 12:04 +0000
                Re: Testing if a pointer is valid Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-09-20 05:25 -0700
                Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-20 16:49 +0000
                Re: Testing if a pointer is valid Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-09-22 22:35 +0300
                Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-23 07:59 +0000
                Re: Testing if a pointer is valid Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-09-23 12:33 +0300
                Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-23 12:23 +0000
                Re: Testing if a pointer is valid Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-09-23 17:34 +0300
                Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-23 17:08 +0000
                Re: Testing if a pointer is valid James Kuyper <jameskuyper@verizon.net> - 2011-09-23 06:49 -0400
                Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-23 12:20 +0000
                Re: Testing if a pointer is valid Seebs <usenet-nospam@seebs.net> - 2011-09-26 22:59 +0000
                Re: Testing if a pointer is valid Michael Press <rubrum@pacbell.net> - 2011-09-30 01:27 -0700
                Re: Testing if a pointer is valid Willem <willem@toad.stack.nl> - 2011-09-30 08:38 +0000
                Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-10-04 12:40 +0000
              Re: Testing if a pointer is valid Kenneth Brody <kenbrody@spamcop.net> - 2011-09-21 12:00 -0400
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-21 21:17 +0200
        Re: Testing if a pointer is valid cri@tiac.net (Richard Harter) - 2011-09-18 23:21 +0000
          Re: Testing if a pointer is valid Keith Thompson <kst-u@mib.org> - 2011-09-18 17:32 -0700
            Re: Testing if a pointer is valid Joe Wright <joewwright@comcast.net> - 2011-09-18 23:10 -0400
              Re: Testing if a pointer is valid gazelle@shell.xmission.com (Kenny McCormack) - 2011-09-19 03:34 +0000
                Re: Testing if a pointer is valid Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2011-09-18 22:32 -0600
                Re: Testing if a pointer is valid gazelle@shell.xmission.com (Kenny McCormack) - 2011-09-20 14:18 +0000
                Re: Testing if a pointer is valid August Karlstrom <fusionfile@gmail.com> - 2011-09-20 18:15 +0200
                Re: Testing if a pointer is valid "BartC" <bc@freeuk.com> - 2011-09-20 17:49 +0100
                Re: Testing if a pointer is valid Willem <willem@toad.stack.nl> - 2011-09-20 17:02 +0000
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-20 20:35 +0200
                Re: Testing if a pointer is valid Ike Naar <ike@iceland.freeshell.org> - 2011-09-20 20:30 +0000
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-20 22:35 +0200
                Re: Testing if a pointer is valid Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-09-22 22:07 +0300
                Re: Testing if a pointer is valid James Kuyper <jameskuyper@verizon.net> - 2011-09-22 16:11 -0400
                Re: Testing if a pointer is valid Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-09-23 12:28 +0300
                Re: Testing if a pointer is valid James Kuyper <jameskuyper@verizon.net> - 2011-09-23 06:44 -0400
                Re: Testing if a pointer is valid Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-09-23 17:33 +0300
                Re: Testing if a pointer is valid James Kuyper <jameskuyper@verizon.net> - 2011-09-23 11:31 -0400
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-23 20:09 +0200
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-23 20:02 +0200
                Re: Testing if a pointer is valid Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-09-23 13:49 -0700
                Re: Testing if a pointer is valid Ian Collins <ian-news@hotmail.com> - 2011-09-24 09:01 +1200
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-23 23:08 +0200
                Re: Testing if a pointer is valid Ian Collins <ian-news@hotmail.com> - 2011-09-24 09:43 +1200
                Re: Testing if a pointer is valid Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-23 22:13 +0100
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-23 23:45 +0200
                Re: Testing if a pointer is valid Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-24 00:01 +0100
                Re: Testing if a pointer is valid Ian Collins <ian-news@hotmail.com> - 2011-09-24 09:47 +1200
                Re: Testing if a pointer is valid James Kuyper <jameskuyper@verizon.net> - 2011-09-23 17:22 -0400
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-23 23:47 +0200
                Re: Testing if a pointer is valid Ian Collins <ian-news@hotmail.com> - 2011-09-24 09:50 +1200
                Re: Testing if a pointer is valid James Kuyper <jameskuyper@verizon.net> - 2011-09-23 18:06 -0400
                Re: Testing if a pointer is valid Ian Collins <ian-news@hotmail.com> - 2011-09-24 10:25 +1200
                Re: Testing if a pointer is valid James Kuyper <jameskuyper@verizon.net> - 2011-09-24 08:02 -0400
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-24 14:13 +0200
                Re: Testing if a pointer is valid Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-24 14:07 +0100
                Re: Testing if a pointer is valid cri@tiac.net (Richard Harter) - 2011-09-24 13:15 +0000
                Re: Testing if a pointer is valid Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-24 15:20 +0100
                Re: Testing if a pointer is valid James Kuyper <jameskuyper@verizon.net> - 2011-09-24 11:28 -0400
                Re: Testing if a pointer is valid Willem <willem@toad.stack.nl> - 2011-09-24 15:45 +0000
                Re: Testing if a pointer is valid Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-09-24 20:07 +0300
                Re: Testing if a pointer is valid Richard Damon <news.x.richarddamon@xoxy.net> - 2011-09-24 14:31 -0400
                Re: Testing if a pointer is valid Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-24 21:49 +0100
                Re: Testing if a pointer is valid Keith Thompson <kst-u@mib.org> - 2011-09-24 14:40 -0700
                Re: Testing if a pointer is valid Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-25 01:14 +0100
                Re: Testing if a pointer is valid Tim Rentsch <txr@alumni.caltech.edu> - 2012-01-24 13:44 -0800
                Re: Testing if a pointer is valid Richard Damon <news.x.richarddamon@xoxy.net> - 2011-09-24 20:23 -0400
                Re: Testing if a pointer is valid Willem <willem@toad.stack.nl> - 2011-09-24 18:44 +0000
                Re: Testing if a pointer is valid James Kuyper <jameskuyper@verizon.net> - 2011-09-25 07:04 -0400
                Re: Testing if a pointer is valid cri@tiac.net (Richard Harter) - 2011-09-24 17:30 +0000
                Re: Testing if a pointer is valid Keith Thompson <kst-u@mib.org> - 2011-09-24 12:34 -0700
                Re: Testing if a pointer is valid Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-09-25 01:00 -0700
                Re: Testing if a pointer is valid Ian Collins <ian-news@hotmail.com> - 2011-09-25 21:30 +1300
                Re: Testing if a pointer is valid Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-09-25 05:08 -0700
                Re: Testing if a pointer is valid Ian Collins <ian-news@hotmail.com> - 2011-09-26 08:39 +1300
                Re: Testing if a pointer is valid Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-09-24 20:04 +0300
                Re: Testing if a pointer is valid James Kuyper <jameskuyper@verizon.net> - 2011-09-23 17:09 -0400
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-23 23:43 +0200
                Re: Testing if a pointer is valid Michael Press <rubrum@pacbell.net> - 2011-09-27 20:48 -0700
                Re: Testing if a pointer is valid Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-10-03 19:59 +0300
                Re: Testing if a pointer is valid Michael Press <rubrum@pacbell.net> - 2011-10-03 17:32 -0700
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-24 13:53 +0100
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-20 21:18 +0100
                Re: Testing if a pointer is valid Willem <willem@toad.stack.nl> - 2011-09-20 20:35 +0000
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-20 22:45 +0200
                Re: Testing if a pointer is valid Willem <willem@toad.stack.nl> - 2011-09-21 08:09 +0000
                Re: Testing if a pointer is valid Noob <root@127.0.0.1> - 2011-09-22 13:04 +0200
                Re: Testing if a pointer is valid Robert Wessel <robertwessel2@yahoo.com> - 2011-09-22 11:38 -0500
                Re: Testing if a pointer is valid Noob <root@127.0.0.1> - 2011-09-23 10:41 +0200
                Re: Testing if a pointer is valid Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-09-22 22:20 +0300
                Re: Testing if a pointer is valid Willem <willem@toad.stack.nl> - 2011-09-22 22:15 +0000
                Re: Testing if a pointer is valid Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-09-23 12:30 +0300
                Re: Testing if a pointer is valid Seebs <usenet-nospam@seebs.net> - 2011-09-26 22:59 +0000
                Re: Testing if a pointer is valid Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-27 02:06 +0100
                Re: Testing if a pointer is valid cri@tiac.net (Richard Harter) - 2011-09-27 03:39 +0000
                Re: Testing if a pointer is valid "Rosario Pulvirenti" <NoInUseno1Spam@non.usare.invalid> - 2011-10-03 19:51 +0200
                Re: Testing if a pointer is valid Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-10-03 19:11 +0100
                Re: Testing if a pointer is valid "Rosario Pulvirenti" <NoInUseno1Spam@non.usare.invalid> - 2011-10-04 16:20 +0200
                Re: Testing if a pointer is valid China Blue Corn Chips <chine.bleu@yahoo.com> - 2011-10-04 08:11 -0700
                Re: Testing if a pointer is valid James Kuyper <jameskuyper@verizon.net> - 2011-10-04 12:19 -0400
                Re: Testing if a pointer is valid Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-09-27 13:56 +0300
                Re: Testing if a pointer is valid Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-27 13:13 +0100
                Re: Testing if a pointer is valid Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-09-27 12:08 +0300
                Re: Testing if a pointer is valid Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-09-29 01:00 -0700
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-20 21:59 +0100
                Re: Testing if a pointer is valid Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-09-22 22:08 +0300
                Re: Testing if a pointer is valid Willem <willem@toad.stack.nl> - 2011-09-20 17:00 +0000
                Re: Testing if a pointer is valid August Karlstrom <fusionfile@gmail.com> - 2011-09-20 20:32 +0200
                Re: Testing if a pointer is valid gazelle@shell.xmission.com (Kenny McCormack) - 2011-09-20 18:53 +0000
                Re: Testing if a pointer is valid August Karlstrom <fusionfile@gmail.com> - 2011-09-20 22:55 +0200
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-20 21:50 +0100
                Re: Testing if a pointer is valid gazelle@shell.xmission.com (Kenny McCormack) - 2011-09-21 15:48 +0000
                Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-21 16:12 +0000
                Re: Testing if a pointer is valid Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-09-21 09:42 -0700
                Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-21 18:01 +0000
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-21 21:00 +0100
                Re: Testing if a pointer is valid August Karlstrom <fusionfile@gmail.com> - 2011-09-21 21:32 +0200
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-22 12:40 +0100
                Re: Testing if a pointer is valid gazelle@shell.xmission.com (Kenny McCormack) - 2011-09-22 13:00 +0000
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-22 14:54 +0100
                Re: Testing if a pointer is valid gazelle@shell.xmission.com (Kenny McCormack) - 2011-09-22 14:03 +0000
                Re: Testing if a pointer is valid Keith Thompson <kst-u@mib.org> - 2011-09-22 11:39 -0700
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-24 13:44 +0100
                Re: Testing if a pointer is valid Keith Thompson <kst-u@mib.org> - 2011-09-24 12:23 -0700
                Re: Testing if a pointer is valid Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-09-29 04:52 -0700
                Re: Testing if a pointer is valid Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-09-29 04:51 -0700
                Re: Testing if a pointer is valid Willem <willem@toad.stack.nl> - 2011-09-20 19:32 +0000
                Re: Testing if a pointer is valid August Karlstrom <fusionfile@gmail.com> - 2011-09-20 22:48 +0200
                Re: Testing if a pointer is valid James Kuyper <jameskuyper@verizon.net> - 2011-09-20 17:29 -0400
                Re: Testing if a pointer is valid August Karlstrom <fusionfile@gmail.com> - 2011-09-20 23:45 +0200
                Re: Testing if a pointer is valid James Kuyper <jameskuyper@verizon.net> - 2011-09-21 10:35 -0400
                Re: Testing if a pointer is valid Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-09-29 05:04 -0700
                Re: Testing if a pointer is valid Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-09-29 04:54 -0700
                Re: Testing if a pointer is valid Keith Thompson <kst-u@mib.org> - 2011-09-20 17:19 -0700
                Re: Testing if a pointer is valid August Karlstrom <fusionfile@gmail.com> - 2011-09-21 23:26 +0200
                Re: Testing if a pointer is valid Keith Thompson <kst-u@mib.org> - 2011-09-21 14:35 -0700
                Re: Testing if a pointer is valid August Karlstrom <fusionfile@gmail.com> - 2011-09-22 00:09 +0200
                Re: Testing if a pointer is valid James Kuyper <jameskuyper@verizon.net> - 2011-09-21 19:08 -0400
                Re: Testing if a pointer is valid cri@tiac.net (Richard Harter) - 2011-09-21 05:25 +0000
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-20 21:11 +0100
                Re: Testing if a pointer is valid August Karlstrom <fusionfile@gmail.com> - 2011-09-20 23:01 +0200
                Re: Testing if a pointer is valid Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-09-21 03:11 -0700
                Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-21 12:16 +0200
                Re: Testing if a pointer is valid Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-09-21 03:23 -0700
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-21 20:44 +0100
                Re: Testing if a pointer is valid August Karlstrom <fusionfile@gmail.com> - 2011-09-21 22:53 +0200
                Re: Testing if a pointer is valid James Kuyper <jameskuyper@verizon.net> - 2011-09-21 23:08 -0400
                Re: Testing if a pointer is valid Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-09-21 21:14 -0700
                Re: Testing if a pointer is valid James Kuyper <jameskuyper@verizon.net> - 2011-09-22 07:17 -0400
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-22 16:37 +0100
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-22 16:25 +0100
                Re: Testing if a pointer is valid Keith Thompson <kst-u@mib.org> - 2011-09-22 11:36 -0700
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-24 13:37 +0100
                Re: Testing if a pointer is valid cri@tiac.net (Richard Harter) - 2011-09-24 13:50 +0000
                Re: Testing if a pointer is valid gazelle@shell.xmission.com (Kenny McCormack) - 2011-09-24 14:47 +0000
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-24 20:43 +0100
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-24 20:26 +0100
                Re: Testing if a pointer is valid Richard Damon <news.x.richarddamon@xoxy.net> - 2011-09-24 20:53 -0400
                Re: Testing if a pointer is valid Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-25 02:30 +0100
                Re: Testing if a pointer is valid Richard Damon <news.x.richarddamon@xoxy.net> - 2011-09-24 22:24 -0400
                Re: Testing if a pointer is valid Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-25 12:36 +0100
                Re: Testing if a pointer is valid Keith Thompson <kst-u@mib.org> - 2011-09-21 13:56 -0700
                Re: Testing if a pointer is valid "Rosario Pulvirenti" <NoInUseno1Spam@non.usare.invalid> - 2011-09-22 07:38 +0200
                Re: Testing if a pointer is valid Keith Thompson <kst-u@mib.org> - 2011-09-22 02:06 -0700
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-22 15:24 +0100
                Re: Testing if a pointer is valid Keith Thompson <kst-u@mib.org> - 2011-09-22 11:35 -0700
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-24 13:25 +0100
                Re: Testing if a pointer is valid Seebs <usenet-nospam@seebs.net> - 2011-09-26 22:59 +0000
                Re: Testing if a pointer is valid Tim Rentsch <txr@alumni.caltech.edu> - 2012-01-24 13:30 -0800
                Re: Testing if a pointer is valid Nobody <nobody@nowhere.com> - 2011-09-22 18:23 +0100
                Re: Testing if a pointer is valid gazelle@shell.xmission.com (Kenny McCormack) - 2011-09-21 15:40 +0000
                Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-21 20:20 +0100
              Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-19 06:39 +0000
                Re: Testing if a pointer is valid Keith Thompson <kst-u@mib.org> - 2011-09-19 10:06 -0700
                Re: Testing if a pointer is valid Kleuskes & Moos <kleuske@somewhere.else.net> - 2011-09-20 07:03 +0000
              Re: Testing if a pointer is valid pete <pfiland@mindspring.com> - 2011-09-19 19:17 -0400
              Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-20 20:57 +0100
            Re: Testing if a pointer is valid cri@tiac.net (Richard Harter) - 2011-09-19 05:14 +0000
              Re: Testing if a pointer is valid Ian Collins <ian-news@hotmail.com> - 2011-09-19 18:02 +1200
                Re: Testing if a pointer is valid cri@tiac.net (Richard Harter) - 2011-09-19 06:18 +0000
            Re: Testing if a pointer is valid August Karlstrom <fusionfile@gmail.com> - 2011-09-19 17:50 +0200
              Re: Testing if a pointer is valid August Karlstrom <fusionfile@gmail.com> - 2011-09-19 20:45 +0200
            Re: Testing if a pointer is valid Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-09-28 08:05 -0700
              Re: Testing if a pointer is valid Keith Thompson <kst-u@mib.org> - 2011-09-28 09:14 -0700
          Re: Testing if a pointer is valid Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-09-18 23:52 -0700
          Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-20 20:45 +0100
            Re: Testing if a pointer is valid August Karlstrom <fusionfile@gmail.com> - 2011-09-20 23:35 +0200
              Re: Testing if a pointer is valid Rui Maciel <rui.maciel@gmail.com> - 2011-09-21 19:53 +0100
  Re: Testing if a pointer is valid "BartC" <bc@freeuk.com> - 2011-09-17 23:54 +0100
    Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-18 00:59 +0200
  Re: Testing if a pointer is valid Heikki Kallasjoki <fis+usenet@zem.fi> - 2011-09-17 23:35 +0000
    Re: Testing if a pointer is valid jacob navia <jacob@spamsink.net> - 2011-09-18 01:47 +0200
  Re: Testing if a pointer is valid Geoff <geoff@invalid.invalid> - 2011-09-17 17:15 -0700
  Re: Testing if a pointer is valid Максим Фомин <maxim@maxim-fomin.ru> - 2011-09-18 00:43 -0700
  Re: Testing if a pointer is valid "Rosario Pulvirenti" <NoInUseno1Spam@non.usare.invalid> - 2011-09-18 10:34 +0200
    Re: Testing if a pointer is valid "Rosario Pulvirenti" <NoInUseno1Spam@non.usare.invalid> - 2011-09-20 09:28 +0200
  Re: Testing if a pointer is valid Ike Naar <ike@iceland.freeshell.org> - 2011-09-18 12:55 +0000
  Re: Testing if a pointer is valid "Joel C. Salomon" <joelcsalomon@gmail.com> - 2011-09-19 10:29 -0400
  Re: Testing if a pointer is valid China Blue Corn Chips <chine.bleu@yahoo.com> - 2011-09-20 00:22 -0700

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