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Groups > comp.lang.c > #10494

Re: Testing if a pointer is valid

From Ben Pfaff <blp@cs.stanford.edu>
Newsgroups comp.lang.c
Subject Re: Testing if a pointer is valid
Date 2011-09-19 08:11 -0700
Message-ID <87zki0wos1.fsf@blp.benpfaff.org> (permalink)
References (8 earlier) <4e767e68.282983130@text.giganews.com> <87d3exxvxq.fsf@blp.benpfaff.org> <4e76baf8.298487352@text.giganews.com> <878vplxhln.fsf@blp.benpfaff.org> <4e76d2e5.304613339@text.giganews.com>

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cri@tiac.net (Richard Harter) writes:

> On Sun, 18 Sep 2011 21:48:36 -0700, blp@cs.stanford.edu (Ben Pfaff)
> wrote:
>
>>cri@tiac.net (Richard Harter) writes:
>>
>>> Mon ami, you miscomprehend.  I did not claim nor do I suppose that I
>>> can determine whether every pointer is valid.  That is not the issue.
>>> It is the viewpoint.  Let me quote:
>>>
>>>     That's the users responsibility, not one the author of the library
>>>     should concern himself with. If the user passes crap to the
>>>     library, a crash (or at least a SIGSEGV) is what's called for.
>>>
>>> The issue is:  As a library author do you validate your input as best
>>> you can and provide a graceful response to input error - again as best
>>> as you can?  Or do you, perhaps, take the view that if "the user
>>> passes crap" it is their lookout.
>>>
>>> If the library author takes the view that the onus is on the crap
>>> passing user and therefore doesn't have to care whether about
>>> validating input or about designing the library software to be robust.
>>> Given my druthers, I'd rather not use software written by such an
>>> author.
>>
>>Personally, I believe that the author of a library should
>>document his assumptions on the input to a library, including the
>>degree to which the library tolerates deviations.  Usually, I
>>would rather carefully use a *fast* library that does not verify
>>its input, instead of a slower library that does.  The former I
>>can transform into the latter with wrapper functions, if
>>necessary; the latter I'm stuck with.
>
> Fair enough, if those are your only choices.  Quite often, however,
> the cost of verification is insignificant.  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?

It's pretty easy to come up with examples of functions that are
trivial if you don't check the arguments and nontrivial if you
do.  An excerpt from a library of mine is below.  Each of these
functions is only one or two machine instructions when inlined.
If the functions were modified to check for null pointers and for
invalid pointers, then they would at least double in code size
(making them less suitable as inline functions) and presumably in
execution time also.

Elsewhere in this thread, Jacob Navia suggested using 64-bit
magic numbers to mark memory regions of a particular type.  That
would also increase the size of this data structure by 40% with
the C implementation that I most commonly use.  Perhaps not
fatal, but definitely significant.

    /* A node in the range set. */
    struct range_set_node
      {
        struct bt_node bt_node;             /* Binary tree node. */
        unsigned long int start;            /* Start of region. */
        unsigned long int end;              /* One past end of region. */
      };

    /* Returns the position of the first 1-bit in NODE. */
    static inline unsigned long int
    range_set_node_get_start (const struct range_set_node *node)
    {
      return node->start;
    }

    /* Returns one past the position of the last 1-bit in NODE. */
    static inline unsigned long int
    range_set_node_get_end (const struct range_set_node *node)
    {
      return node->end;
    }

    /* Returns the number of contiguous 1-bits in NODE. */
    static inline unsigned long int
    range_set_node_get_width (const struct range_set_node *node)
    {
      return node->end - node->start;
    }


-- 
Ben Pfaff 
http://benpfaff.org

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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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