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.
42 #ifdef __GLASGOW_HASKELL__
73 #ifdef __GLASGOW_HASKELL__
76 #if (WORD_SIZE_IN_BITS == 32 || WORD_SIZE_IN_BITS == 64)
77 instance Show (Ptr a) where
78 showsPrec p (Ptr a) rs = pad_out (showHex (word2Integer(int2Word#(addr2Int# a))) "") rs
80 -- want 0s prefixed to pad it out to a fixed length.
82 '0':'x':(replicate (2*SIZEOF_HSPTR - length ls) '0') ++ ls ++ rs
83 -- word2Integer :: Word# -> Integer (stolen from Word.lhs)
84 word2Integer w = case word2Integer# w of
87 instance Show (FunPtr a) where
88 showsPrec p = showsPrec p . castFunPtrToPtr
91 -- | Release the storage associated with the given 'FunPtr', which
92 -- must have been obtained from a wrapper stub. This should be called
93 -- whenever the return value from a foreign import wrapper function is
94 -- no longer required; otherwise, the storage it uses will leak.
95 foreign import ccall unsafe "freeHaskellFunctionPtr"
96 freeHaskellFunPtr :: FunPtr a -> IO ()