Re: Feature request : More lightuserdata types

["Soni \"They/Them\" L." <fakedme@...>]

On 2022-02-22 10:24, 云风 Cloud Wu wrote:
>
>
> Flyer31 Test <flyer31@googlemail.com>于2022年2月22日 周二20:50写道：
>
>     Why don't you just use "normal c userdata", if you want metafunctions?
>     (I assume that in this case your userdata quite sure is anyway somehow
>     "more important" / more "heavy"?).
>
>
> userdata is a GC object , and we don’t need lua manage the lifespan of
> objects.
>
> For example, we have a game scene graph in C side, only a few objects
> (when needed) export into lua side. So,not all C object has the lua proxy.
>
> Userdata is only a reference to scene node. We need another (weak)
> table to cache them. (Scene node pointer-> userdata)
>
> Another usecase is fixed-point number or complex number library. A
> value type is much cheaper than GC object.
>
>
>

You probably want a full userdata to avoid UB. LU aren't collected, so
you can't know if it's still alive or not/when to free it/etc.

"Optimizations" like these are a security nightmare.

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> -- 
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