Re: Reference counting

From	Shao Miller <sha0.miller@gmail.com>
Newsgroups	comp.lang.c
Subject	Re: Reference counting
Date	2011-06-14 13:46 -0500
Organization	A noiseless patient Spider
Message-ID	<it86pu$m22$1@dont-email.me> (permalink)
References	(1 earlier) <65a066fe-3455-4bae-90ef-d966d5d3f513@h7g2000yqa.googlegroups.com> <it7238$hbd$1@dont-email.me> <slrnive3iq.31t.angel+news@pearlgates.net> <ln1uyw5rjk.fsf@nuthaus.mib.org> <68718339-7621-456c-a4f7-941d07f038f7@g12g2000yqd.googlegroups.com>

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On 6/14/2011 12:23 PM, luser- -droog wrote:
> On Jun 14, 11:03 am, Keith Thompson<ks...@mib.org>  wrote:
>> Angel<angel+n...@spamcop.net>  writes:
>>> On 2011-06-14, Shao Miller<sha0.mil...@gmail.com>  wrote:
>>>> For hashing, is the object representation of a 'void *' guaranteed to be
>>>> the same any time a 'void *' points to the same object?  Is it likely?
>>>> (I think so.) :)
>>
>>> The standard only says pointers are represented in an
>>> implementation-defined manner. But as long as the pointer value doesn't
>>> change, I doubt the representation will. On most implementations, a
>>> pointer is really just a 32- or 64-bit unsigned number, indicating a
>>> certain spot in virtual memory.
>>
>> Quibble: Pointer representation is unspecified, not
>> implementation-defined.  The difference is that an implementation
>> aren't required to document its pointer representation(s).
>>
>
> Does that make it even more seat-of-the-pants than guessing alignment?
>

Well alignment-guessing seems straight-forward, at least.  N1570 
has[6.2.8p4] that "... Every valid alignment value shall be a 
nonnegative integral power of two."  Which 4 KiB satisfies, for 
example...  Plenty of room for a reference count, a 'size_t' for the 
object, a pointer to a handler function for OO "messages," a signature 
for the original allocator, a UUID, a doubly-linked-list entry, a 
'jmp_buf', some opcode bytes, a checksum of the header...

Thread

Reference counting daknok <radekslupik@gmail.com> - 2011-06-05 12:52 +0200
  Re: Reference counting Angel <angel+news@spamcop.net> - 2011-06-05 11:17 +0000
    Re: Reference counting Gene <gene.ressler@gmail.com> - 2011-06-06 20:07 -0700
      Multiple Inheritance (Was Re: Reference counting) Shao Miller <sha0.miller@gmail.com> - 2011-06-11 03:57 -0500
        Re: Multiple Inheritance (Was Re: Reference counting) Dr Nick <3-nospam@temporary-address.org.uk> - 2011-06-12 07:22 +0100
  Re: Reference counting China Blue Angels <chine.bleu@yahoo.com> - 2011-06-05 05:07 -0700
  Re: Reference counting "BartC" <bc@freeuk.com> - 2011-06-05 13:14 +0100
    Re: Reference counting daknok <daknok@example.com> - 2011-06-05 14:22 +0200
      Re: Reference counting "BartC" <bc@freeuk.com> - 2011-06-05 14:45 +0100
        Re: Reference counting daknok <daknok@example.com> - 2011-06-05 17:01 +0200
          Re: Reference counting Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-06-05 18:06 -0400
          Re: Reference counting Dr Nick <3-nospam@temporary-address.org.uk> - 2011-06-12 07:25 +0100
  Re: Reference counting daknok <daknok@example.com> - 2011-06-05 15:29 +0200
  Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-05 12:17 -0500
  Re: Reference counting cri@tiac.net (Richard Harter) - 2011-06-05 17:11 +0000
  Re: Reference counting ImpalerCore <jadill33@gmail.com> - 2011-06-10 11:30 -0700
    Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-10 16:04 -0400
    Re: Reference counting James Kuyper <jameskuyper@verizon.net> - 2011-06-10 22:56 -0400
      Re: Reference counting ImpalerCore <jadill33@gmail.com> - 2011-06-11 12:36 -0700
        Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-11 17:23 -0500
          Re: Reference counting luser- -droog <mijoryx@yahoo.com> - 2011-06-12 15:15 -0700
            Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-12 21:13 -0500
              Re: Reference counting "Chris M. Thomasson" <cristom@charter.net> - 2011-06-13 12:37 -0700
                Re: Reference counting "Chris M. Thomasson" <cristom@charter.net> - 2011-06-13 12:54 -0700
                Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-13 16:40 -0500
          Re: Reference counting ImpalerCore <jadill33@gmail.com> - 2011-06-13 07:34 -0700
            Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-13 14:26 -0500
              Re: Reference counting ImpalerCore <jadill33@gmail.com> - 2011-06-13 12:47 -0700
                Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-13 17:33 -0500
                Re: Reference counting ImpalerCore <jadill33@gmail.com> - 2011-06-14 12:14 -0700
                Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-15 02:16 -0500
                Re: Reference counting "Chris M. Thomasson" <cristom@charter.net> - 2011-06-15 15:34 -0700
                Re: Reference counting "Chris M. Thomasson" <cristom@charter.net> - 2011-06-15 15:42 -0700
                Re: Reference counting "Chris M. Thomasson" <cristom@charter.net> - 2011-06-16 13:45 -0700
                Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-16 17:02 -0500
                Re: Reference counting "Chris M. Thomasson" <cristom@charter.net> - 2011-06-16 15:18 -0700
                Re: Reference counting "Chris M. Thomasson" <cristom@charter.net> - 2011-06-16 16:01 -0700
                Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-16 18:44 -0500
                Re: Reference counting "Chris M. Thomasson" <cristom@charter.net> - 2011-06-16 17:11 -0700
                Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-16 18:39 -0500
        Re: Reference counting "Chris M. Thomasson" <cristom@charter.net> - 2011-06-11 16:51 -0700
          Re: Reference counting "Chris M. Thomasson" <cristom@charter.net> - 2011-06-11 18:28 -0700
            Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-12 16:10 -0500
            Re: Reference counting ImpalerCore <jadill33@gmail.com> - 2011-06-13 07:36 -0700
      Re: Reference counting Tim Rentsch <txr@alumni.caltech.edu> - 2011-06-14 15:00 -0700
  Re: Reference counting luser- -droog <mijoryx@yahoo.com> - 2011-06-13 21:46 -0700
    Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-14 03:19 -0500
      Re: Reference counting Angel <angel+news@spamcop.net> - 2011-06-14 07:31 +0000
        Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-14 05:02 -0500
        Re: Reference counting Keith Thompson <kst-u@mib.org> - 2011-06-14 09:03 -0700
          Re: Reference counting luser- -droog <mijoryx@yahoo.com> - 2011-06-14 10:23 -0700
            Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-14 13:46 -0500
          Re: Reference counting Tim Rentsch <txr@alumni.caltech.edu> - 2011-06-14 15:05 -0700
            Re: Reference counting Keith Thompson <kst-u@mib.org> - 2011-06-14 16:44 -0700
              Re: Reference counting Tim Rentsch <txr@alumni.caltech.edu> - 2011-06-15 06:54 -0700
                Re: Reference counting Keith Thompson <kst-u@mib.org> - 2011-06-15 08:46 -0700
                Re: Reference counting pete <pfiland@mindspring.com> - 2011-06-15 22:19 -0400
                Re: Reference counting James Kuyper <jameskuyper@verizon.net> - 2011-06-15 23:03 -0400
                Re: Reference counting Tim Rentsch <txr@alumni.caltech.edu> - 2011-06-19 14:48 -0700
        Re: Reference counting Seebs <usenet-nospam@seebs.net> - 2011-06-14 17:16 +0000
    Re: Reference counting luser- -droog <mijoryx@yahoo.com> - 2011-06-14 20:53 -0700
      Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-16 18:49 -0500
  Re: Reference counting "io_x" <a@b.c.invalid> - 2011-06-14 08:30 +0200
    Re: Reference counting "io_x" <a@b.c.invalid> - 2011-06-14 09:15 +0200
      Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-14 04:21 -0500
      Re: Reference counting "io_x" <a@b.c.invalid> - 2011-06-16 10:35 +0200
        Re: Reference counting Ian Collins <ian-news@hotmail.com> - 2011-06-16 20:36 +1200
        Re: Reference counting "io_x" <a@b.c.invalid> - 2011-06-16 11:21 +0200
          Re: Reference counting "io_x" <a@b.c.invalid> - 2011-06-19 17:57 +0200
          Re: Reference counting "io_x" <a@b.c.invalid> - 2011-06-19 20:01 +0200
            Re: Reference counting Keith Thompson <kst-u@mib.org> - 2011-06-19 11:07 -0700
            Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-19 23:15 -0500
              Re: Reference counting "io_x" <a@b.c.invalid> - 2011-06-20 08:21 +0200
        Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-16 19:05 -0500
          Re: Reference counting Ian Collins <ian-news@hotmail.com> - 2011-06-17 12:09 +1200
  Re: Reference counting luser- -droog <mijoryx@yahoo.com> - 2011-06-15 08:40 -0700
  Re: Reference counting "christian.bau" <christian.bau@cbau.wanadoo.co.uk> - 2011-06-16 11:08 -0700
    Re: Reference counting Shao Miller <sha0.miller@gmail.com> - 2011-06-16 14:42 -0400

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