1 {-# OPTIONS_GHC -fno-implicit-prelude #-}
2 -----------------------------------------------------------------------------
4 -- Module : Foreign.Ptr
5 -- Copyright : (c) The FFI task force 2001
6 -- License : BSD-style (see the file libraries/base/LICENSE)
8 -- Maintainer : ffi@haskell.org
9 -- Stability : provisional
10 -- Portability : portable
12 -- This module provides typed pointers to foreign data. It is part
13 -- of the Foreign Function Interface (FFI) and will normally be
14 -- imported via the "Foreign" module.
16 -----------------------------------------------------------------------------
24 castPtr, -- :: Ptr a -> Ptr b
25 plusPtr, -- :: Ptr a -> Int -> Ptr b
26 alignPtr, -- :: Ptr a -> Int -> Ptr a
27 minusPtr, -- :: Ptr a -> Ptr b -> Int
29 -- * Function pointers
31 FunPtr, -- data FunPtr a
32 nullFunPtr, -- :: FunPtr a
33 castFunPtr, -- :: FunPtr a -> FunPtr b
34 castFunPtrToPtr, -- :: FunPtr a -> Ptr b
35 castPtrToFunPtr, -- :: Ptr a -> FunPtr b
37 freeHaskellFunPtr, -- :: FunPtr a -> IO ()
38 -- Free the function pointer created by foreign export dynamic.
40 -- * Integral types with lossless conversion to/from pointers
49 #ifdef __GLASGOW_HASKELL__
59 import GHC.Word ( Word(..) )
61 import Data.Typeable ( Typeable(..), mkTyCon, mkTyConApp )
63 import Foreign.C.Types
65 import Foreign.Storable
91 #ifdef __GLASGOW_HASKELL__
92 -- | Release the storage associated with the given 'FunPtr', which
93 -- must have been obtained from a wrapper stub. This should be called
94 -- whenever the return value from a foreign import wrapper function is
95 -- no longer required; otherwise, the storage it uses will leak.
96 foreign import ccall unsafe "freeHaskellFunctionPtr"
97 freeHaskellFunPtr :: FunPtr a -> IO ()
99 #include "HsBaseConfig.h"
102 -- | An unsigend integral type that can be losslessly converted to and from
104 INTEGRAL_TYPE(WordPtr,tyConWordPtr,"WordPtr",Word)
105 -- Word and Int are guaranteed pointer-sized in GHC
107 -- | A sigend integral type that can be losslessly converted to and from
109 INTEGRAL_TYPE(IntPtr,tyConIntPtr,"IntPtr",Int)
110 -- Word and Int are guaranteed pointer-sized in GHC
112 -- | casts a @Ptr@ to a @WordPtr@
113 ptrToWordPtr :: Ptr a -> WordPtr
114 ptrToWordPtr (Ptr a#) = WordPtr (W# (int2Word# (addr2Int# a#)))
116 -- | casts a @WordPtr@ to a @Ptr@
117 wordPtrToPtr :: WordPtr -> Ptr a
118 wordPtrToPtr (WordPtr (W# w#)) = Ptr (int2Addr# (word2Int# w#))
120 -- | casts a @Ptr@ to an @IntPtr@
121 ptrToIntPtr :: Ptr a -> IntPtr
122 ptrToIntPtr (Ptr a#) = IntPtr (I# (addr2Int# a#))
124 -- | casts an @IntPtr@ to a @Ptr@
125 intPtrToPtr :: IntPtr -> Ptr a
126 intPtrToPtr (IntPtr (I# i#)) = Ptr (int2Addr# i#)