[Haskell-cafe] FPS: Finalizers not running (was Memory usage outside of the Haskell heap)

Joel Reymont joelr1 at gmail.com
Sun Nov 6 09:29:05 EST 2005


I followed your suggestion and I think the finalizers for FPS are not  

Please take a look at http://wagerlabs.com/Bar.hs to see what I mean.  
I had to modify the FPS export list to expose the constructor but  
that's the only change I made.

The other useful tidbits are:

-- (internal) GC wrapper of mallocForeignPtrArray
mallocForeignPtr :: Int -> IO (ForeignPtr Word8)
mallocForeignPtr l = when (l > 1000000) performGC >>  
mallocForeignPtrArray l


createPS :: Int -> (Ptr Word8 -> IO ()) -> FastString
createPS l write_ptr = unsafePerformIO $ do
     fp <- mallocForeignPtr l
     withForeignPtr fp $ \p -> write_ptr p
     return $ PS fp 0 l

I replaced mallocForeignPtr with a call to mallocForeignBytes but  
that did not make a difference, the finalizers still don't run.


On Nov 5, 2005, at 4:57 PM, David Roundy wrote:

> You can attach a print message to the finalizer and also print a  
> message
> out when creating the string.  I've found this to be helpful at times.


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