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Groups > comp.lang.c > #5918

Re: Reference counting

From Shao Miller <sha0.miller@gmail.com>
Newsgroups comp.lang.c
Subject Re: Reference counting
Date 2011-06-12 16:10 -0500
Organization A noiseless patient Spider
Message-ID <it3a0r$9f8$1@dont-email.me> (permalink)
References (1 earlier) <e9ef06c1-e30d-4953-8f15-d72b2bdde0eb@k17g2000vbn.googlegroups.com> <isulh0$ipq$1@dont-email.me> <52c902de-0f66-4bb0-b787-8c440c2405db@hg8g2000vbb.googlegroups.com> <8cTIp.4134$SG4.3519@newsfe03.iad> <ICUIp.1369$UT4.718@newsfe05.iad>

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On 6/11/2011 8:28 PM, Chris M. Thomasson wrote:
> "Chris M. Thomasson"<cristom@charter.net>  wrote in message
> news:8cTIp.4134$SG4.3519@newsfe03.iad...
>> "ImpalerCore"<jadill33@gmail.com>  wrote in message
>> news:52c902de-0f66-4bb0-b787-8c440c2405db@hg8g2000vbb.googlegroups.com...
>>
>> [...]
>>
>>> Unfortunately I do not know how
>>> to manually find a platform's ALIGN_MAX.  I've seen some incantations
>>> with unions and offsetof, and autoconf has their AC_CHECK_ALIGNOF, but
>>> I don't know how to use it.
>>
>> read all of these:
> [...]
>
>>
>> the `ALIGN_OF()' function macro should always give you a "sufficient"
>> alignment for a given type.
>

To pull it into this thread, your macro is:

   #define ALIGN_OF(mp_type) \
       offsetof( \
           struct \
           { \
                 char pad_ALIGN_OF; \
                 mp_type type_ALIGN_OF; \
           }, \
           type_ALIGN_OF \
       )

Your macro is quite nice for C89 & C99 in that:
- it expands to a meaningful alignment suggestion
- it should be an integer constant expression

One possible disadvantage for C99 is that you cannot use it with a 
variably-modified type.

> What about [...]
>
> http://codepad.org/A65Noc37
>
> lol...
>

In my opinion, the "union of many types" approach:
- can waste space
- is not a guaranteed maximum alignment requirement because it mightn't 
include all types
- requires that any types used for members be in scope (some might need 
to be #included)
- is likely to work anyway

'ref_count_acquire', 'ref_count_release' and 'main' might benefit from 
checking for null pointers, but I doubt you were asking for that kind of 
criticism. ;)

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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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