Re: __gc finalizer called at exit?
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- Subject: Re: __gc finalizer called at exit?
- From: Norman Ramsey <nr@...>
- Date: 2007年12月11日 22:25:02 -0500
> > I've scrutinized the reference manual and also done some web searching,
> > and nowhere do I find the answer to this question: if Lua exits either by
> > a call to os.exit or by a normal return from the main chunk, does it
> > guarantee to call the __gc finalizers for any live userdata objects?
>
> No and yes. The 'lua' applicative calls lua_close before returning,
> and so clears everything. A call to os.exit skips that closing. We
> thought about adding lua_close in an atexit function, but leaved as
> it is so there is a way to skip lua_close if needed. (This may speed
> up some programs which finish with lots of data to clean up.)
Hmm. I wouldn't like to make that decision myself without some
experimental evidence.
So suppose I do the following:
local exit = os.exit
local pairs = pairs
local insert = table.insert
local collectgarbage = collectgarbage
local function wipe(t)
local keys = { }
for k in pairs(t) do insert(keys, k) end
for _, k in pairs(keys) do t[k] = nil end
end
os.exit = function(n) wipe(_G); collectgarbage 'collect'; exit(n) end
I still worry that there may be live variables on the stack that don't
get finalized. Any ideas what I can do about that?
It's annoying that a function passed to atexit() won't take a parameter!
I assume this is why there's no os.atexit in Lua...
Norman