From: Victor Porton <porton@narod.ru>
Subject: Re: Allocators design flaw
Date: Sat, 14 Oct 2017 19:42:50 +0300
Date: 2017-10-14T19:42:50+03:00 [thread overview]
Message-ID: <orteq9$11h$1@gioia.aioe.org> (raw)
In-Reply-To: ortbcq$1qki$1@gioia.aioe.org
Dmitry A. Kazakov wrote:
> On 2017-10-14 17:18, Victor Porton wrote:
>> Dmitry A. Kazakov wrote:
>>
>>> On 2017-10-14 16:03, Victor Porton wrote:
>>>> Dmitry A. Kazakov wrote:
>>>>
>>>>> When freed use the stored offset to
> ^^^^^^^^^^^^^^^^^^^^^^^^
>>>>> get the original address.
> ^^^^^^^^^^^^^^^^^^^^^^^^
>
>>>> As far as I understand, it will not work, because the C library I am
>>>> writing bindings for may try to free an object allocated by me (or I my
>>>> need to free an object allocated by the library).
>>>
>>> The last sentence describes freeing memory, i.e. for Deallocate.
>>
>> I again state that we need the C function *_free() to free memory. But it
>> is impossible in your scenario, because you change the pointer to point
>> to another byte of memory.
>
> Re-read the last sentence of my response.
No Dmitry, you don't understand me.
We may pass the allocated address to a C function.
1. This C function may need to get some data from the struct. In this case
we need to pass into C the shifted address.
2. This C function may call *_free() with the address of the struct. In this
case we need to pass into C the original allocation address.
Thus the same address we pass into a C function is both original and
shifted. This is a clear contradiction.
--
Victor Porton - http://portonvictor.org
next prev parent reply other threads:[~2017-10-14 16:42 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-14 2:53 Allocators design flaw Victor Porton
2017-10-14 7:27 ` Dmitry A. Kazakov
2017-10-14 13:52 ` Victor Porton
2017-10-14 14:25 ` Dmitry A. Kazakov
2017-10-14 14:03 ` Victor Porton
2017-10-14 14:26 ` Dmitry A. Kazakov
2017-10-14 15:18 ` Victor Porton
2017-10-14 15:44 ` Dmitry A. Kazakov
2017-10-14 16:42 ` Victor Porton [this message]
2017-10-14 16:13 ` Simon Wright
2017-10-14 16:38 ` Victor Porton
2017-10-14 14:12 ` Victor Porton
2017-10-14 14:20 ` Victor Porton
2017-10-14 14:24 ` Victor Porton
2017-10-14 14:36 ` Dmitry A. Kazakov
2017-10-14 15:17 ` Victor Porton
2017-10-14 15:51 ` Dmitry A. Kazakov
2017-10-14 16:34 ` Victor Porton
2017-10-14 17:14 ` Dmitry A. Kazakov
2017-10-14 17:24 ` Victor Porton
2017-10-14 18:08 ` Dmitry A. Kazakov
2017-10-14 14:28 ` Dmitry A. Kazakov
2017-10-14 15:14 ` Victor Porton
2017-10-14 15:42 ` Simon Wright
2017-10-14 16:29 ` Victor Porton
2017-10-14 20:07 ` Simon Wright
2017-10-14 21:26 ` Victor Porton
2017-10-21 1:42 ` Randy Brukardt
2017-10-14 8:02 ` Simon Wright
2017-10-14 13:59 ` Victor Porton
2017-10-14 14:35 ` Simon Wright
2017-10-14 15:11 ` Victor Porton
2017-10-14 15:56 ` Simon Wright
2017-10-14 16:22 ` Victor Porton
2017-10-29 16:01 ` David Thompson
2017-10-14 14:11 ` Victor Porton
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