[Haskell-cafe] Problem with finalizers

[Neil Davies]

Ivan

If I remember correctly there is a caveat in the documentation that
stdin/stdout could be closed when the finalizer is called. So It may
be being called - you just can see it!

Neil

On 11/05/07, Ivan Tomac <tomac at pacific.net.au> wrote:
> Why does the finalizer in the following code never get called unless I
> explicitly call finalizeForeignPtr fptr?
> Even adding System.Mem.performGC made no difference.
>
> The code was compiled with ghc --make -fffi -fvia-c Test.hs
>
> Ivan
>
> -------------------- Test.hs ------------------------
>
> module Main where
>
> import Foreign.Ptr
> import Foreign.ForeignPtr
> import Foreign.Marshal.Utils
>
> import System.Mem
>
> foreign import ccall safe "ctest.h &ctest" ctestPtr :: FunPtr (Ptr Int -> IO
> ())
>
> test :: Int -> IO ()
> test i = with i test'
>     where
>         test' ptr = do fptr <- newForeignPtr ctestPtr ptr
>                        putStrLn "test"
> --                       finalizeForeignPtr fptr
>
> main = do putStrLn "before test..."
>           test 33
>           putStrLn "after test..."
>           performGC
>
> --------------------- ctest.h ----------------------
>
> #include <stdio.h>
>
> static inline void ctest( int *i )
> {
>     printf( "finalizer called with: %d\n", *i );
> }
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