Re: C pointer semantics with dynamically allocated struct

From	Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups	comp.lang.c
Subject	Re: C pointer semantics with dynamically allocated struct
Date	2015-10-03 20:36 +0100
Organization	A noiseless patient Spider
Message-ID	<878u7jpwwv.fsf@bsb.me.uk> (permalink)
References	(16 earlier) <9122d591-296e-4acf-a5c3-baf448f6b87c@googlegroups.com> <87si5tqloh.fsf@bsb.me.uk> <fa9f2a9e-716b-41c8-9065-9b80f4385f19@googlegroups.com> <87h9m9qd67.fsf@bsb.me.uk> <39591d0f-05c8-4aaa-99e9-283fade3d012@googlegroups.com>

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"Rick C. Hodgin" <rick.c.hodgin@gmail.com> writes:

> On Friday, October 2, 2015 at 3:32:49 PM UTC-4, Ben Bacarisse wrote:
<snip>
>> Undefined behaviour has a specific technical meaning in the C standard,
>> and accessing a member from a union that is not the last one stored is
>> *not* undefined behaviour.  Lots of people seem to think that C has
>> changed in this regard, but I don't think it has.  It was never UB, and
>> it still is not UB.
>> 
>> After union { float f; uint32_t u; } u = { .f = 3.14 }; the expression
>> u.u does not result in undefined behaviour.  Because uint32_t has no
>> padding bits (and thus no trap representations), u.u is guaranteed to be
>> one of the 2^32 integer values a uint32_t can hold.  Naturally, the C
>> standard declines to say exactly what value it will be, but the
>> behaviour is not undefined, merely unspecified.
>
> I'm curious what the difference is between unspecified and undefined
> behavior in this context.

The standard defines:

  3.4.3
  1 undefined behavior
    behavior, upon use of a nonportable or erroneous program construct
    or of erroneous data, for which this International Standard imposes
    no requirements
  2 NOTE Possible undefined behavior ranges from ignoring the situation
    completely with unpredictable results, to behaving during
    translation or program execution in a documented manner
    characteristic of the environment (with or without the issuance of a
    diagnostic message), to terminating a translation or execution (with
    the issuance of a diagnostic message).

and

  3.4.4
  1 unspecified behavior
    use of an unspecified value, or other behavior where this
    International Standard provides two or more possibilities and
    imposes no further requirements on which is chosen in any instance

So, to make this concrete, if the union access in question were
undefined behaviour, a helpful debugging implementation of C would be
permitted to make a note of the last member stored and use that to stop
the program with a message "ERROR: accessing a different union member
to the one last stored".  This behaviour would be conforming.

However, that is not permitted.  The result of the access is not
undefined by simply unspecified -- some value must be produced form the
object's  bits.

In this case, the standard is being a bit coy because, whilst it is true
that it does not formally impose any further requirements on the value
chosen, a footnotes does explain what is to be expected:

  If the member used to read the contents of a union object is not the
  same as the member last used to store a value in the object, the
  appropriate part of the object representation of the value is
  reinterpreted as an object representation in the new type as described
  in 6.2.6 (a process sometimes called "type punning"). This might be a
  trap representation.

Footnotes are described as being "for information only" rather than
being a formally binding part of the language standard, but it's still
information even if that is all it is.

-- 
Ben.

Thread

Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-09-29 09:49 -0700
  Re: C pointer semantics with dynamically allocated struct wssimms@gmail.com - 2015-09-30 21:18 -0700
    Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-01 09:35 -0700
      Re: C pointer semantics with dynamically allocated struct "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-10-01 09:41 -0700
        Re: C pointer semantics with dynamically allocated struct gazelle@shell.xmission.com (Kenny McCormack) - 2015-10-01 18:34 +0000
          Re: C pointer semantics with dynamically allocated struct "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-10-01 12:02 -0700
    Re: C pointer semantics with dynamically allocated struct raltbos@xs4all.nl (Richard Bos) - 2015-10-02 13:03 +0000
      Re: C pointer semantics with dynamically allocated struct "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-10-02 06:20 -0700
        Re: C pointer semantics with dynamically allocated struct Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-02 16:07 +0100
          Re: C pointer semantics with dynamically allocated struct "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-10-02 08:46 -0700
            Re: C pointer semantics with dynamically allocated struct Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-02 17:28 +0100
              Re: C pointer semantics with dynamically allocated struct "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-10-02 10:30 -0700
                Re: C pointer semantics with dynamically allocated struct Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-02 20:32 +0100
                Re: C pointer semantics with dynamically allocated struct "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-10-02 12:58 -0700
                Re: C pointer semantics with dynamically allocated struct Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-02 22:06 +0100
                Re: C pointer semantics with dynamically allocated struct "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-10-03 09:31 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-03 14:31 -0700
                Re: C pointer semantics with dynamically allocated struct "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-10-03 09:27 -0700
                Re: C pointer semantics with dynamically allocated struct Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-03 20:36 +0100
                Re: C pointer semantics with dynamically allocated struct "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-10-03 13:00 -0700
                Re: C pointer semantics with dynamically allocated struct Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-03 23:37 +0100
                Re: C pointer semantics with dynamically allocated struct "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-10-03 17:07 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-03 17:42 -0700
                Re: C pointer semantics with dynamically allocated struct "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-10-03 17:49 -0700
                Re: C pointer semantics with dynamically allocated struct Richard Damon <Richard@Damon-Family.org> - 2015-10-03 23:28 -0400
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-04 00:10 -0700
                Re: C pointer semantics with dynamically allocated struct Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-04 13:24 +0100
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-04 14:07 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-04 14:40 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-04 18:04 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-04 20:10 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-04 22:15 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-05 08:53 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-06 08:45 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-06 12:34 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-06 17:16 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-06 21:47 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-07 11:05 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-07 11:47 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-07 13:50 -0700
                Re: C pointer semantics with dynamically allocated struct James Kuyper <jameskuyper@verizon.net> - 2015-10-07 18:10 -0400
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-07 16:10 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-07 16:33 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-08 09:08 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-08 10:43 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-08 11:50 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-08 12:19 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-07 15:32 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-07 16:21 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-08 08:54 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-08 11:15 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-08 12:38 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-08 13:30 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-08 14:15 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-08 14:53 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-08 15:23 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-08 17:24 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-09 08:02 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-09 09:02 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-09 12:43 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-09 14:21 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-09 15:14 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-13 18:37 -0700
                Re: C pointer semantics with dynamically allocated struct Martin Shobe <martin.shobe@yahoo.com> - 2015-10-07 20:56 -0500
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-07 19:41 -0700
                Re: C pointer semantics with dynamically allocated struct James Kuyper <jameskuyper@verizon.net> - 2015-10-07 23:15 -0400
                Re: C pointer semantics with dynamically allocated struct raltbos@xs4all.nl (Richard Bos) - 2015-10-14 10:05 +0000
                Re: C pointer semantics with dynamically allocated struct Richard Heathfield <rjh@cpax.org.uk> - 2015-10-14 11:23 +0100
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-14 08:24 -0700
                Re: C pointer semantics with dynamically allocated struct raltbos@xs4all.nl (Richard Bos) - 2015-10-16 11:12 +0000
                Re: C pointer semantics with dynamically allocated struct Gareth Owen <gwowen@gmail.com> - 2015-10-16 21:55 +0100
                Re: C pointer semantics with dynamically allocated struct Les Cargill <lcargill99@comcast.com> - 2015-10-16 22:08 -0500
                Re: C pointer semantics with dynamically allocated struct James Kuyper <jameskuyper@verizon.net> - 2015-10-14 11:44 -0400
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-14 11:12 -0700
                Re: C pointer semantics with dynamically allocated struct raltbos@xs4all.nl (Richard Bos) - 2015-10-07 10:34 +0000
                Re: C pointer semantics with dynamically allocated struct James Kuyper <jameskuyper@verizon.net> - 2015-10-07 07:23 -0400
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-07 09:53 -0700
                Re: C pointer semantics with dynamically allocated struct raltbos@xs4all.nl (Richard Bos) - 2015-10-14 10:13 +0000
                Re: C pointer semantics with dynamically allocated struct James Kuyper <jameskuyper@verizon.net> - 2015-10-14 11:36 -0400
                Re: C pointer semantics with dynamically allocated struct Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-04 13:35 +0100
                Re: C pointer semantics with dynamically allocated struct "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-10-04 06:23 -0700
                Re: C pointer semantics with dynamically allocated struct Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-04 15:34 +0100
                Re: C pointer semantics with dynamically allocated struct "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2015-10-04 08:07 -0700
                Re: C pointer semantics with dynamically allocated struct glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-04 14:42 +0000
                Re: C pointer semantics with dynamically allocated struct raltbos@xs4all.nl (Richard Bos) - 2015-10-04 15:37 +0000
                Re: C pointer semantics with dynamically allocated struct Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-05 00:33 +0100
                Re: C pointer semantics with dynamically allocated struct raltbos@xs4all.nl (Richard Bos) - 2015-10-14 10:20 +0000
                Re: C pointer semantics with dynamically allocated struct Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-14 13:55 +0100
                Re: C pointer semantics with dynamically allocated struct Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-04 22:06 -0700
                Re: C pointer semantics with dynamically allocated struct raltbos@xs4all.nl (Richard Bos) - 2015-10-14 10:30 +0000
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-14 08:39 -0700
                Re: C pointer semantics with dynamically allocated struct glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-14 23:47 +0000
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-15 10:20 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-15 11:10 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-15 12:11 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-15 12:35 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-15 13:52 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-15 14:35 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-15 15:51 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-16 06:48 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-16 08:50 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-16 10:06 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-16 12:45 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-16 13:56 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-16 14:29 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-16 14:52 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-16 15:32 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-16 15:59 -0700
                Re: C pointer semantics with dynamically allocated struct glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-17 00:03 +0000
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-17 00:08 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-17 15:26 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-17 16:38 -0700
                Re: C pointer semantics with dynamically allocated struct glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-16 23:43 +0000
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-16 23:57 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-17 14:50 -0700
                Re: C pointer semantics with dynamically allocated struct Ian Collins <ian-news@hotmail.com> - 2015-10-18 10:55 +1300
                Re: C pointer semantics with dynamically allocated struct James Kuyper <jameskuyper@verizon.net> - 2015-10-17 18:24 -0400
                Re: C pointer semantics with dynamically allocated struct Richard Damon <Richard@Damon-Family.org> - 2015-10-17 18:39 -0400
                Re: C pointer semantics with dynamically allocated struct James Kuyper <jameskuyper@verizon.net> - 2015-10-17 18:56 -0400
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-17 16:17 -0700
                Re: C pointer semantics with dynamically allocated struct James Kuyper <jameskuyper@verizon.net> - 2015-10-18 11:46 -0400
                Re: C pointer semantics with dynamically allocated struct Richard Damon <Richard@Damon-Family.org> - 2015-10-17 19:44 -0400
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-17 16:48 -0700
                Re: C pointer semantics with dynamically allocated struct Richard Heathfield <rjh@cpax.org.uk> - 2015-10-18 01:14 +0100
                Re: C pointer semantics with dynamically allocated struct Richard Damon <Richard@Damon-Family.org> - 2015-10-17 20:22 -0400
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-17 17:26 -0700
                Re: C pointer semantics with dynamically allocated struct Richard Heathfield <rjh@cpax.org.uk> - 2015-10-18 01:44 +0100
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-17 20:09 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-18 11:24 -0700
                Re: C pointer semantics with dynamically allocated struct glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-19 04:42 +0000
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-19 16:24 -0700
                Re: C pointer semantics with dynamically allocated struct glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-20 02:20 +0000
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-19 19:53 -0700
                Re: C pointer semantics with dynamically allocated struct glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-20 09:41 +0000
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-17 19:53 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-17 16:07 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-17 14:55 -0700
                Re: C pointer semantics with dynamically allocated struct glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-18 04:28 +0000
                Re: C pointer semantics with dynamically allocated struct Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-15 12:49 -0700
                Re: C pointer semantics with dynamically allocated struct Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-15 12:26 -0700
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-15 12:48 -0700
                Re: C pointer semantics with dynamically allocated struct Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-17 08:21 -0700
                Re: C pointer semantics with dynamically allocated struct Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-04 22:23 -0700
          Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-02 09:10 -0700
            Re: C pointer semantics with dynamically allocated struct Martin Shobe <martin.shobe@yahoo.com> - 2015-10-02 11:58 -0500
              Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-02 11:38 -0700
                Re: C pointer semantics with dynamically allocated struct Martin Shobe <martin.shobe@yahoo.com> - 2015-10-05 09:36 -0500
                Re: C pointer semantics with dynamically allocated struct Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-12 09:47 -0700
                Re: C pointer semantics with dynamically allocated struct glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-13 02:51 +0000
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-12 23:45 -0700
                Re: C pointer semantics with dynamically allocated struct Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-15 13:54 -0700
                Re: C pointer semantics with dynamically allocated struct glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-16 01:07 +0000
                Re: C pointer semantics with dynamically allocated struct Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-19 15:33 -0700
            Re: C pointer semantics with dynamically allocated struct Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-02 19:21 +0100
              Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-02 12:10 -0700
                Re: C pointer semantics with dynamically allocated struct Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-02 21:24 +0100
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-02 14:32 -0700
                Re: C pointer semantics with dynamically allocated struct Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-02 23:43 +0100
                Re: C pointer semantics with dynamically allocated struct supercat@casperkitty.com - 2015-10-02 16:49 -0700
                Re: C pointer semantics with dynamically allocated struct Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-03 02:01 +0100
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-03 00:38 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-02 16:10 -0700
                Re: C pointer semantics with dynamically allocated struct Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-04 21:54 -0700
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-05 08:19 -0700
          Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-02 15:16 -0700
            Re: C pointer semantics with dynamically allocated struct glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-02 22:52 +0000
              Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-03 00:48 -0700
                Re: C pointer semantics with dynamically allocated struct glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-03 08:22 +0000
                Re: C pointer semantics with dynamically allocated struct Keith Thompson <kst-u@mib.org> - 2015-10-03 12:05 -0700
              Re: C pointer semantics with dynamically allocated struct Richard Damon <Richard@Damon-Family.org> - 2015-10-03 16:38 -0400
            Re: C pointer semantics with dynamically allocated struct Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-03 00:00 +0100
              Re: C pointer semantics with dynamically allocated struct Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-04 22:16 -0700

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