ForeignPtr and -threaded

[Bulat Ziganshin]

Hello PHO,

Sunday, July 22, 2007, 5:36:27 PM, you wrote:

> [2] Foreign.ForeignPtr

> The following code prints nothing when it isn't linked with -threaded
> RTS, but when it is, it *sometimes* prints "called" but not always.

> import Foreign.Marshal.Alloc
> import Foreign.Ptr
> import Foreign.ForeignPtr

> foreign import ccall "wrapper"
>         mkFinalizer :: (Ptr () -> IO ()) -> IO (FunPtr (Ptr () -> IO ()))

> main = do mem <- mallocBytes 10
>           fin <- mkFinalizer $ \ _ -> print "called"
>           newForeignPtr fin mem

try to add performGC at end - this should force collecting garbage and
therefore printing of string. otherwise, it's ok - there is no guarantee
that GC will be performed and therefore that you finalizer will be
performed. it's rather stanard behavior for GC languages - finalizers
are almosr useless there


-- 
Best regards,
 Bulat                            mailto:Bulat.Ziganshin at gmail.com