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|
{-# OPTIONS -fno-implicit-prelude #-}
-----------------------------------------------------------------------------
-- |
-- Module : Foreign.StablePtr
-- Copyright : (c) The University of Glasgow 2001
-- License : BSD-style (see the file libraries/base/LICENSE)
--
-- Maintainer : ffi@haskell.org
-- Stability : provisional
-- Portability : portable
--
-- This module is part of the Foreign Function Interface (FFI) and will usually
-- be imported via the module "Foreign".
--
-----------------------------------------------------------------------------
module Foreign.StablePtr
( -- * Stable references to Haskell values
StablePtr -- abstract
, newStablePtr -- :: a -> IO (StablePtr a)
, deRefStablePtr -- :: StablePtr a -> IO a
, freeStablePtr -- :: StablePtr a -> IO ()
, castStablePtrToPtr -- :: StablePtr a -> Ptr ()
, castPtrToStablePtr -- :: Ptr () -> StablePtr a
, -- ** The C-side interface
-- $cinterface
) where
#ifdef __GLASGOW_HASKELL__
import GHC.Stable
import GHC.Err
#endif
#ifdef __HUGS__
import Hugs.StablePtr
#endif
#ifdef __NHC__
import NHC.FFI
( StablePtr
, newStablePtr
, deRefStablePtr
, freeStablePtr
, castStablePtrToPtr
, castPtrToStablePtr
)
#endif
-- $cinterface
--
-- The following definition is available to C programs inter-operating with
-- Haskell code when including the header @HsFFI.h@.
--
-- > typedef void *HsStablePtr; /* C representation of a StablePtr */
--
-- Note that no assumptions may be made about the values representing stable
-- pointers. In fact, they need not even be valid memory addresses. The only
-- guarantee provided is that if they are passed back to Haskell land, the
-- function 'deRefStablePtr' will be able to reconstruct the
-- Haskell value refereed to by the stable pointer.
|
