From: Lutz Donnerhacke <lutz@iks-jena.de>
Subject: Re: Limited_Controlled types as 'out' arguments
Date: Wed, 30 Jul 2003 12:32:17 +0000 (UTC)
Date: 2003-07-30T12:32:17+00:00 [thread overview]
Message-ID: <slrnbifemd.o6.lutz@taranis.iks-jena.de> (raw)
In-Reply-To: stcfivs5gk0u0gvhefqohlmhjheg1gshl0@4ax.com
* Dmitry A Kazakov wrote:
> On Wed, 30 Jul 2003 11:31:03 +0000 (UTC), Lutz Donnerhacke
>> procedure Copy(to : out Test; from : Test);
>>
>>Clearly, the variable 0 and 3 are never finalized. How implement I this
>>correctly (without refering to the rosen trick).
>
> 1. Why do you think that it is incorrect? Copy does not destruct the
> target, so why should it call Finalize?
In my implementation, the type Test contains an array_access, I have to
deallocate, before assigning a new value. I can not deallocate this access
variable, because the procedure Free (unchecked_deallocate) requires an
'in out' Parameter. But I only have an 'out' paramter. So I can't read it,
before the first write.
In short: The former contents (despite discriminates) of an 'out' parameter
are not available inside the procedure. So the former contents are not
finalizable inside this procedure.
> procedure Copy (To : in out Test'Class; From : Test'Class) is
> begin
> Destruct (To);
> Construct (To, From);
> end Copy;
Fine, but try this with the prototype:
procedure Copy (To : out Test'Class; From : Test'Class);
> Beware, true multiple dispatch is not supported in Ada. So if you want
> to copy objects of different types you have to simulate MD.
Wrong answer. Not every problem is MI related.
next prev parent reply other threads:[~2003-07-30 12:32 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-07-30 11:31 Limited_Controlled types as 'out' arguments Lutz Donnerhacke
2003-07-30 12:22 ` Dmitry A. Kazakov
2003-07-30 12:32 ` Lutz Donnerhacke [this message]
2003-07-30 14:24 ` Dmitry A. Kazakov
2003-07-30 14:25 ` Lutz Donnerhacke
2003-07-30 14:48 ` Dmitry A. Kazakov
2003-07-30 15:15 ` Lutz Donnerhacke
2003-07-31 10:26 ` Dmitry A. Kazakov
2003-07-31 10:54 ` Lutz Donnerhacke
2003-07-31 11:50 ` Dmitry A. Kazakov
2003-07-31 12:19 ` Lutz Donnerhacke
2003-07-31 13:15 ` Dmitry A. Kazakov
2003-07-31 17:51 ` Randy Brukardt
2003-07-30 15:01 ` Vinzent Hoefler
2003-07-30 15:16 ` Lutz Donnerhacke
2003-07-30 15:52 ` Lutz Donnerhacke
2003-07-30 19:30 ` Randy Brukardt
2003-07-31 7:43 ` Lutz Donnerhacke
2003-07-30 12:31 ` Matthew Heaney
2003-07-30 12:57 ` Lutz Donnerhacke
2003-07-30 13:47 ` Martin Dowie
2003-07-30 17:06 ` Matthew Heaney
2003-07-30 12:37 ` Martin Dowie
2003-07-30 12:59 ` Lutz Donnerhacke
2003-07-30 13:41 ` Martin Dowie
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