Re: A way to associate a Lua value with a FFI pointer?
- From: Daniel Kolesa <quaker66@xxxxxxxxx>
- To: luajit@xxxxxxxxxxxxx
- Date: Wed, 9 Apr 2014 10:09:15 +0100
Yes, a mapping table is always a possibility, I was hoping for some way to
do it without this though. Also, I don't think you really need the
tonumber() here. Indexing tables with cdata is fine here, as we want the
key to be the address, the problem with cdata table indexes is just when
doing something like, tbl[5LL] == tbl[5].
2014-04-09 10:02 GMT+01:00 Richard Hundt <richardhundt@xxxxxxxxx>:
> On 4/9/14 10:54 AM, Daniel Kolesa wrote:
> > Hello,
> >
> > I would like to know if there is any way to associate a generic Lua
> > value with a FFI pointer.
>
> I'm not sure if I have the full context, but I do this sort of thing:
>
> ```
> local reg = { }
> function setptrvalue(ptr, val)
> local key = tonumber(ffi.cast('intptr_t', ptr))
> reg[key] = val
> end
> function getptrvalue(ptr)
> local key = tonumber(ffi.cast('intptr_t', ptr))
> return reg[key]
> end
> ```
>
> You can always get your pointer back from `intptr_t` with a cast.
>
>
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