Re: Large writable variables

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От Robert Haas
Тема Re: Large writable variables
Дата
Msg-id CA+TgmoZw-JZEJacyboSJvZs28dUNhwOOTb9KUV4CVmP3UB5Gqg@mail.gmail.com
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Ответ на Re: Large writable variables  (Andres Freund <andres@anarazel.de>)
Ответы Re: Large writable variables  (Andres Freund <andres@anarazel.de>)
Список pgsql-hackers
On Tue, Oct 16, 2018 at 12:26 PM Andres Freund <andres@anarazel.de> wrote:
> /*
>  * Macro that allows to cast constness away from a variable, but doesn't
>  * allow changing the underlying type.  Enforcement of the latter
>  * currently only works for gcc like compilers.
>  *
>  * Please note IT IS NOT SAFE to cast constness away if the variable will ever
>  * be modified (it would be undefined behaviour). Doing so anyway can cause
>  * compiler misoptimizations or runtime crashes (modifying readonly memory).
>  * It is only safe to use when the the variabble will not be modified, but API
>  * design or language restrictions prevent you from declaring that
>  * (e.g. because a function returns both const and non-const variables).
>  */

"variabble" is a little too rich in "b"s.

In terms of a function that returns both const and non-const
variables, it seems a bit sketchy that the caller would know what the
function is doing in particular cases and make decisions based on it,
but maybe that's just how life is.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company


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