Re: garbage collection and setfenv
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- Subject: Re: garbage collection and setfenv
- From: "Matthew Armstrong" <turkeypotpie@...>
- Date: 2008年3月18日 18:57:15 -0700
I had already tried the setfenv(tryThis, {}) idea, and it didn't work. After your mail, I also tried tryThis = nil, which also didn't work. Here is my non-trimmed code:
function tryThis()
myVar = GfcTimer()
local mt = getmetatable(myVar)
mt.__gc = function()
print("!!! cleanup")
ldb()
end
--myVar = nil
end
function yup()
local env = {}
setmetatable(env, { __index = _G })
setfenv(tryThis, env)
tryThis()
setfenv(tryThis, {})
tryThis = nil
env = nil
collectgarbage()
end
yup()
Note: there is one external function, GfcTimer, which generates a userdata object from our library.
If I uncomment the line:
-- myVar = nil
... then I get a confirmed call to the __gc method.
Can you see anything else which would maintain a reference?
On Tue, Mar 18, 2008 at 5:55 PM, Roberto Ierusalimschy <
roberto@inf.puc-rio.br> wrote:
> So let's say I say:
>
> function tryThis()
> myVar = { foo="baz" }
> end
>
> local env = {}
> setfenv(tryThis, env)
> tryThis()
>
> My question is: when does myVar get collected? With my current testing, it
> seems that myVar never gets collected. If so, how do I "convince" it to be
> collected?
collected until tryThis is garbage or until you change its environment
again. You may try "tryThis = nil" or "setfenv(tryThis, {})".
-- Roberto