Re: C pointer semantics with dynamically allocated struct

From	glen herrmannsfeldt <gah@ugcs.caltech.edu>
Newsgroups	comp.lang.c
Subject	Re: C pointer semantics with dynamically allocated struct
Date	2015-10-20 02:20 +0000
Organization	Aioe.org NNTP Server
Message-ID	<n048e9$6v6$1@speranza.aioe.org> (permalink)
References	(7 earlier) <473cd3ca-4387-482f-b8f7-7a9e094b2468@googlegroups.com> <mvupso$flj$1@dont-email.me> <5f9b205b-a13a-43b7-b9b7-b91995426386@googlegroups.com> <n01sc0$om0$1@speranza.aioe.org> <43be31fe-5669-4d5a-86d9-e491f1f27f94@googlegroups.com>

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supercat@casperkitty.com wrote:
>> > I would regard as a defect in the Standard the fact that code like:
  
>> >    unsigned short mul_mod_65536(unsigned short a, unsigned short b)
>> >    {
>> >      return a*b;
>> >    }
  
>> > has no defined behaviors which on any platform which differ from those where
>> > UINT_MAX==USHRT_MAX, and has fully-defined behaviors on all platforms where
>> > either UINT_MAX==USHRT_MAX or UINT_MAX/USHRT_MAX > 2u*USHRT_MAX, but will
>> > invoke Undefined Behavior on platforms where UINT_MAX is larger than
>> > USHRT_MAX but not large enough to prevent overflow.

(snip, then I wrote)
>> I would say don't do that. 
 
>> For one, you are assuming short is 16 bits.
 
> Poorly named function.  Originally I'd written the code using uint16_t, but
> the issue goes back to C89 while those types only go back to C99, so I
> changed the code to use "unsigned short" rather than "uint16_t" but didn't
> change the function name suitably.

I suppose, but it seems to me that you should write independent of the
actual widths when possible. If you really need a modulo 65536, you
should code for that, maybe with an &0xffff.
 
>> But why would you want to do that?
 
> Unsigned values are often used for quantities which should logically "wrap
> around"; it is because of such usage that the C Standard requires that
> implementations must not trap the wrap-around behavior.  An example of a
> usage case where the situation might arise, consider a function that is
> supposed to output N copies of a 16-bit word and update a 16-bit ones'
> complement checksum.  A reasonable approach which will work perfectly on
> any system where "int" is 16 bits or 64 bits, but may fail on systems
> where "int" is 32 bits, would be:

Does it work right if you cast to (unsigned int) before the multiply?

Then the question relates the optimization, and if the compiler can
figure out how to do it right.
 
>    void update_checksum_for_write_multiple(
>         uint16_t dat, uint16_t n, uint16_t *checksum)
>    {
>      *checksum -= dat*n;
>    }
 
> Nice and simple, but to ensure defined behavior on 32-bit systems would
> require that the function be written as "*checksum -= (0u+dat)*n;" or some
> variation thereof.  The promotion is needed not because code needs a
> 32-bit result, but merely to ensure that the system will compute the bottom
> 16 bits without invoking Undefined Behavior.

It would be nice to have a high-level language with an operator of
function to do multipication giving the double width product.

As well as I know, given

int i, j;
long long k;  /* double the size of int */
   k=(long long)i*j;

compilers figure out not to do three multiplies by zero.

(I was doing this some years ago on IA32 processors.)
 
>> But if you did, you should well understant the C promotion rules
>> and the effect of them in the case of overflow.
 
> The above code would work perfectly on a 16-bit system (and many compilers
> for vintage 8-bit and 16-bit CPU platforms don't have brilliant optimizers,
> and thus may waste time on adding 0 to the indicated value).  How likely
> would somebody porting a code base from a vintage system to a more modern
> be to notice the need to coerce the values before performing the multiply?

Yes, but that is true for many other reasons, and others would appear if
you changed the promotion rules.
 
>> Personally, I believe that the promotion rules more often give the 
>> desired answer than not, but otherwise they are something that C
>> programmers need to learn. 
 
> A major problem with the promotion rules is that the so-called "fixed-size
> types" have semantics which vary depending upon the size of "int".  This
> can often have the effect that code which works perfectly on the platform
> for which it was written may malfunction in bizarre ways when ported to a
> different platform.  While the effects of many of the rules are rather
> entrenched, most of them will yield behavior which, when wrong, will be
> deterministically so.  The Undefined Behavior at issue here is far more
> insidious because while it is very unlikely to result in the value being
> miscalculated, it's actually more likely to result in other bizarre and
> seemingly-unrelated problems.  For example, given the code:
 
>    if (rom_expansion_installed) // 128Kbyte instead of 32Kbyte option
>      update_checksum_for_write_multiple(0xFFFF, 0xC000, *csum);
 
> which is supposed to calculate the effect of adding 49152 blank words
> to the checksum (Most programmable ROM devices are all 1's when erased)

That is true for the 2708 and descendants. I believe the pMOS 1702
erased to zeros. 

I am not sure about 28xx chips, which are more common now than EPROMs.


> may instead cause some compilers to infer that "rom_expansion_installed"
> cannot be true, and thus nullify the effect of all code which is supposed
> to be applicable to 128K-expanded units.
 
>> OK, but as in other discussions, is there enough reason to add such a
>> feature? How often is it that someone would want to do this, and how
>> hard is it to do within the current C rules?
 
> There exists a huge variety of code which requires a wrapping 32-bit integer
> type.  Porting such code to platforms where "int" is 64 bits is often
> a major task fraught with danger, since there are lots of subtleties which
> may be hard to catch in a code inspection.

Seems to me that code that is wrapping 32 bit integers is likely to
fail for other reason when int gets to 64 bits.  That is, assuming
that larger values also have meaning.

I do remember lots of programs failing when reading files >=2GB, 
even if they didn't do any fseek() or ftell(). 

-- glen

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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