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From: Brian May <bam@snoopy.apana.org.au>
Subject: Re: Is this a bug?
Date: Fri, 24 Sep 2004 08:26:34 +1000
Date: 2004-09-24T08:26:34+10:00	[thread overview]
Message-ID: <sa4mzzg62qt.fsf@snoopy.apana.org.au> (raw)
In-Reply-To: 2rg6a1F1arg02U1@uni-berlin.de

>>>>> "Nick" == Nick Roberts <nick.roberts@acm.org> writes:

    Nick> Wojtek Narczynski wrote:
    >> Okay, I wasn't thinking. It obviously isn't a compiler bug.

    Nick> To clarify (hopefully), there is a line which changes the
    Nick> value of Current_Hook:

    Nick>     Current_Hook := Current_Hook.all.Down'Unchecked_Access;

    Nick> The value of Current would not have been changed by this
    Nick> statement, so it would presumably have been left referring
    Nick> to the wrong thing. The code shown is quite complex, and
    Nick> Wojtek can be forgiven for initially missing this (in my
    Nick> humble opinion).

So another words, if I did the following:

declare
   ...
   Current : Bucket_Access renames Current_Hook.all;

begin
   ...
   Current_Hook := <something else>
   ...
end;


Then Current would still be the same object and value it use to be?

If so, then "renames" isn't quite as simple as I thought. It is more
like a "hard link" then a "symbolic link". i.e. it links to the object
rather then the name of the object. Interesting.

Question: If you freed the value (with unchecked_deallocate) of
"Current_Hook" would the value of "Current" still be valid? I suspect
it would not be valid, as "Current" is now dangling.
-- 
Brian May <bam@snoopy.apana.org.au>



  reply	other threads:[~2004-09-23 22:26 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-09-23  0:52 Is this a bug? Wojtek Narczynski
2004-09-23  8:35 ` Wojtek Narczynski
2004-09-23 14:52   ` Nick Roberts
2004-09-23 22:26     ` Brian May [this message]
2004-09-24  0:28       ` Stephen Leake
2004-09-24  0:57         ` Jeffrey Carter
2004-09-24 12:47         ` Wojtek Narczynski
2004-09-25  0:17           ` Brian May
2004-09-24 12:37       ` Wojtek Narczynski
2004-09-23 11:27 ` Jeff C r e e.m
2004-09-24  0:30   ` Stephen Leake
2004-09-24  1:49     ` Jeff C r e e.m
2004-09-25 12:59       ` Stephen Leake
2004-10-04 16:36         ` Warren W. Gay VE3WWG
  -- strict thread matches above, loose matches on Subject: below --
2019-12-30 15:44 reinert
2019-12-30 17:51 ` Anh Vo
2019-12-30 18:41   ` Niklas Holsti
2019-12-30 19:50     ` reinert
2019-12-30 20:11       ` Dmitry A. Kazakov
2019-12-30 23:16     ` Randy Brukardt
2019-12-31 19:40       ` Optikos
2019-12-31 21:50         ` Randy Brukardt
2020-01-02  9:34           ` Dmitry A. Kazakov
2020-01-03  7:26             ` reinert
2020-01-03  7:35             ` reinert
2020-01-03  8:37               ` Dmitry A. Kazakov
2020-01-04  0:42                 ` Randy Brukardt
2020-01-05 13:32                   ` reinert
2020-01-06 10:43                     ` J-P. Rosen
2020-01-06 12:19                       ` Tero Koskinen
2020-01-17  9:54                 ` reinert
2020-01-17 10:08                   ` Dmitry A. Kazakov
2020-01-17 22:14                   ` Randy Brukardt
2019-12-31  6:08     ` J-P. Rosen
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