[fpc-pascal] Implementation of variant records
Florian Klaempfl
florian at freepascal.org
Sat Jul 6 21:21:18 CEST 2019
Am 05.07.2019 um 13:53 schrieb Ralf Quint:
> On 7/5/2019 3:27 AM, Marco van de Voort wrote:
>>
>> Op 2019-07-05 om 11:49 schreef Bernd Oppolzer:
>>>
>>> IMO, the variants in a variant record should always overlay correctly
>>> (like unions in C),
>>> so the variant part should start at offset 32 in this case, and this
>>> is where all three
>>> variants should start.
>>
>> This is not a guarantee case in the Pascal language, afaik many old
>> compilers don't even try, but make fields sequential.
>>
>> As soon as you have expections of overlaying, you are dialect and
>> architecture specific.
>
> Shouldn't a PACKED Record guarantee that values are aligned at the byte
> level?
It does in TP, but the ISO says only that it shall be economised.
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