Re: Pointers in custom types

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От Will Harrower
Тема Re: Pointers in custom types
Дата
Msg-id 49A03EA5.1090805@doc.ic.ac.uk
обсуждение исходный текст
Ответ на Re: Pointers in custom types  (Tom Lane <tgl@sss.pgh.pa.us>)
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Tom Lane wrote:
> Will Harrower <wjh105@doc.ic.ac.uk> writes:
>
>> I'm writing a custom type in C that needs to manage two byte arrays
>> (among other things). I have attempted to implement this using something
>> similar to the following struct (along with corresponding input and
>> output functions):
>>
>
>
>> typedef struct example {
>>     bytea* first;
>>     bytea* second;
>> } example;
>>
>
> You can't do that; the value of a datatype has to be a single chunk of
> memory, and it has to be independent of exactly where it's stored
> because it will get copied around without modification.
>
>             regards, tom lane
>

Ok, that makes sense, thanks. Guess I'll stick to a bytea and an extra
index.

Cheers,
Will.

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