From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Is this actually possible?
Date: Wed, 11 Dec 2019 20:58:48 +0100
Date: 2019-12-11T20:58:48+01:00 [thread overview]
Message-ID: <qsrhpq$3o7$1@gioia.aioe.org> (raw)
In-Reply-To: 69c7677b-4aec-4db2-b240-de6b69f762b9@googlegroups.com
On 2019-12-11 18:54, Lucretia wrote:
> On Wednesday, 11 December 2019 17:38:40 UTC, Dmitry A. Kazakov wrote:
>> On 2019-12-11 17:43, Lucretia wrote:
>>
>>> I was thinking about extensible records recently (not tagged types), and thought to try to export a tagged type to C, not C++. It compiles, but the results aren't quite right, so wondering if it's possible or not.
>>>
>>> The idea is to export an array of tagged types as a C array to either a function or a variable / struct element. i.e.
>>
>> Ada objects of tagged types have varying size and keep tag inside. Both
>> make them utterly incompatible with C.
>
> I know this, but as the compiler let it go through, I wondered if the tag would be stored elsewhere and not with the tagged type.
Not with tagged types which have T <-> T'Class view conversions.
> Otherwise, shouldn't the compiler complain?
No idea.
If you need objects that could be packed into C arrays use a variant
record with the choice discriminant having a default.
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
next prev parent reply other threads:[~2019-12-11 19:58 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-11 16:43 Is this actually possible? Lucretia
2019-12-11 17:38 ` Dmitry A. Kazakov
2019-12-11 17:54 ` Lucretia
2019-12-11 19:55 ` Randy Brukardt
2019-12-11 19:58 ` Dmitry A. Kazakov [this message]
2019-12-11 21:12 ` Lucretia
2019-12-11 21:34 ` Dmitry A. Kazakov
2019-12-12 2:00 ` Randy Brukardt
2019-12-12 9:26 ` Niklas Holsti
2020-04-08 16:10 ` Alejandro R. Mosteo
2019-12-12 10:17 ` Lucretia
2019-12-12 14:32 ` Dmitry A. Kazakov
2019-12-12 15:14 ` Lucretia
2019-12-12 15:15 ` Lucretia
2019-12-12 18:24 ` Dmitry A. Kazakov
2019-12-12 18:30 ` Lucretia
2019-12-12 19:09 ` Dmitry A. Kazakov
2019-12-12 20:54 ` Lucretia
2019-12-12 21:12 ` Dmitry A. Kazakov
2019-12-13 11:11 ` Lucretia
2019-12-11 19:59 ` Randy Brukardt
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