1 % ------------------------------------------------------------------------------
2 % $Id: PrelForeign.lhs,v 1.19 2001/05/18 16:54:05 simonmar Exp $
4 % (c) The University of Glasgow, 1994-2000
7 \section[Foreign]{Module @Foreign@}
10 {-# OPTIONS -fno-implicit-prelude #-}
12 module PrelForeign where
15 import PrelNum -- for fromInteger
20 %*********************************************************
22 \subsection{ForeignPtr}
24 %*********************************************************
27 data ForeignPtr a = ForeignPtr ForeignObj#
28 instance CCallable (ForeignPtr a)
30 eqForeignPtr :: ForeignPtr a -> ForeignPtr a -> Bool
32 = unsafePerformIO (primEqForeignPtr mp1 mp2) /= (0::Int)
34 foreign import "eqForeignObj" unsafe
35 primEqForeignPtr :: ForeignPtr a -> ForeignPtr a -> IO Int
37 instance Eq (ForeignPtr a) where
38 p == q = eqForeignPtr p q
39 p /= q = not (eqForeignPtr p q)
41 newForeignPtr :: Ptr a -> IO () -> IO (ForeignPtr a)
42 newForeignPtr p finalizer
43 = do fObj <- mkForeignPtr p
44 addForeignPtrFinalizer fObj finalizer
47 addForeignPtrFinalizer :: ForeignPtr a -> IO () -> IO ()
48 addForeignPtrFinalizer (ForeignPtr fo) finalizer =
49 IO $ \s -> case mkWeak# fo () finalizer s of { (# s1, w #) -> (# s1, () #) }
51 mkForeignPtr :: Ptr a -> IO (ForeignPtr a) {- not exported -}
52 mkForeignPtr (Ptr obj) = IO ( \ s# ->
53 case mkForeignObj# obj s# of
54 (# s1#, fo# #) -> (# s1#, ForeignPtr fo# #) )
56 touchForeignPtr :: ForeignPtr a -> IO ()
57 touchForeignPtr (ForeignPtr fo)
58 = IO $ \s -> case touch# fo s of s -> (# s, () #)
60 withForeignPtr :: ForeignPtr a -> (Ptr a -> IO b) -> IO b
62 = do r <- io (foreignPtrToPtr fo)
66 foreignPtrToPtr :: ForeignPtr a -> Ptr a
67 foreignPtrToPtr (ForeignPtr fo) = Ptr (foreignObjToAddr# fo)
69 castForeignPtr (ForeignPtr a) = ForeignPtr a