Re: Coroutines and FFI
- From: Coda Highland <chighland@xxxxxxxxx>
- To: luajit@xxxxxxxxxxxxx
- Date: Wed, 25 Mar 2015 12:28:57 -0700
On Wed, Mar 25, 2015 at 12:26 PM, Soni L. <fakedme+lj@xxxxxxxxx> wrote:
>
>
> On 25/03/15 04:20 PM, Ryan Gonzalez wrote:
>
> You mean you're trying to pass a coroutine to a C function? That's pretty
> much impossible. Unless I'm misreading your message.
>
> BTW, I like your Google+ profile picture. :)
>
> On Wed, Mar 25, 2015 at 2:14 PM, Soni L. <fakedme+lj@xxxxxxxxx> wrote:
>>
>>
>>
>> On 25/03/15 04:04 PM, Coda Highland wrote:
>>>
>>> On Wed, Mar 25, 2015 at 8:29 AM, Soni L. <fakedme+lj@xxxxxxxxx> wrote:
>>>>
>>>> Why can't I pass coroutines thru the FFI as lua_State*s?
>>>
>>> Simply put, the FFI is not intended to interact with Lua at all.
>>> Accessing the Lua state while an FFI call is on the stack is undefined
>>> behavior and is very likely to blow up in your face.
>>>
>>> (Accessing a DIFFERENT global Lua state via FFI is perfectly safe, as
>>> the LuaJIT interpreter is reentrant.)
>>>
>>> /s/ Adam
>>>
>> So... I can't have custom userdata? :/
>>
>> Hmm... What about adding custom userdata creation to the FFI? (for both
>> heavy and light userdatum)
>>
>
>
>
> --
> Ryan
> [ERROR]: Your autotools build scripts are 200 lines longer than your
> program. Something’s wrong.
> http://kirbyfan64.github.io/
>
>
> Well, technically...
>
> I would use a Lua function (e.g. function f(L) <something> =
> C.lua_newuserdata(L, <something>); return 1; end), cast it to a C function,
> then use FFI to register the function, then call it to generate a custom
> userdata.
That sounds very inefficient. You should prefer to either exclusively
use the FFI (and therefore cdata) or exclusively use Lua code (and
therefore use tables) -- LuaJIT is tuned around these two behaviors,
and using the Lua C API is comparatively very slow. (If you REALLY
MUST use what you describe, then use the Lua C API instead of trying
to make the FFI do it.)
/s/ Adam
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