Re: Memory Leak

On Jan 27, 2009, at 1:07 PM, Shawn Garbett wrote:

> I'm pulling my hair out fixing a memory leak in an OpenGL program.  
> Don't know if this is related to OpenGL, but I've not gotten any  
> takers from IRC. I know the exact line of code that's causing it.
>

<snip>

I've gotten it down to this:

import Data.IORef
import Graphics.Rendering.OpenGL.GL.StateVar

-- THIS VERSION DOESN'T LEAK
--iter :: IORef Integer -> IO ()
--iter ref = do
--  i <- get ref
--  ref $=! ((i+1) `rem` 12)
--  iter ref
--
--main = do
--    ref <- newIORef (0::Integer)
--    iter ref

-- THIS VERSION DOESN'T LEAK
--data State = State { stuff :: IORef Integer }
--
--iter :: State -> IO ()
--iter state = do
--  i <- get $ stuff state
--  (stuff state) $=! ((i + 1) `rem` 12)
--  iter state
--
--main = do
--  ref <- newIORef (0::Integer)
--  iter State{stuff=ref}

-- LEAKS LIKE A SIEVE
data Leak = Leak {x :: Integer}
data State = State { stuff :: IORef Leak }

iter :: State -> IO ()
iter state = do
   l <- get $ stuff state
   (stuff state) $=! l{x=((x l) + 1 `rem` 12)}
   iter state

main :: IO ()
main = do
   l <- newIORef $ Leak{x=0}
   let s = State{stuff = l}
   iter s

> Shawn Garbett <shawn.p.garbett > at < vanderbilt.edu>
> Vanderbilt Cancer Biology
> 220 Pierce Ave, PRB 715AA
> Nashville, TN 37232
> Office: 615.936.1975
> Cell: 615.397.8737