\begin{code}
-{-# OPTIONS -fno-implicit-prelude #-}
+{-# OPTIONS_GHC -fno-implicit-prelude #-}
-----------------------------------------------------------------------------
-- |
-- Module : GHC.Conc
--
-----------------------------------------------------------------------------
+-- #hide
module GHC.Conc
( ThreadId(..)
, pseq -- :: a -> b -> b
, yield -- :: IO ()
, labelThread -- :: ThreadId -> String -> IO ()
- , forkProcess -- :: IO Int
-- Waiting
, threadDelay -- :: Int -> IO ()
, isEmptyMVar -- :: MVar a -> IO Bool
, addMVarFinalizer -- :: MVar a -> IO () -> IO ()
- ) where
+ -- TVars
+ , STM -- abstract
+ , atomically -- :: STM a -> IO a
+ , retry -- :: STM a
+ , orElse -- :: STM a -> STM a -> STM a
+ , catchSTM -- :: STM a -> (Exception -> STM a) -> STM a
+ , TVar -- abstract
+ , newTVar -- :: a -> STM (TVar a)
+ , readTVar -- :: TVar a -> STM a
+ , writeTVar -- :: a -> TVar a -> STM ()
+ , unsafeIOToSTM -- :: IO a -> STM a
+
+#ifdef mingw32_HOST_OS
+ , asyncRead -- :: Int -> Int -> Int -> Ptr a -> IO (Int, Int)
+ , asyncWrite -- :: Int -> Int -> Int -> Ptr a -> IO (Int, Int)
+ , asyncDoProc -- :: FunPtr (Ptr a -> IO Int) -> Ptr a -> IO Int
+
+ , asyncReadBA -- :: Int -> Int -> Int -> Int -> MutableByteArray# RealWorld -> IO (Int, Int)
+ , asyncWriteBA -- :: Int -> Int -> Int -> Int -> MutableByteArray# RealWorld -> IO (Int, Int)
+#endif
+ ) where
+
+import System.Posix.Types
+import System.Posix.Internals
+import Foreign
+import Foreign.C
import Data.Maybe
import GHC.Base
-import GHC.IOBase ( IO(..), MVar(..) )
+import GHC.IOBase
+import GHC.Num ( Num(..) )
+import GHC.Real ( fromIntegral, quot )
import GHC.Base ( Int(..) )
import GHC.Exception ( Exception(..), AsyncException(..) )
import GHC.Pack ( packCString# )
+import GHC.Ptr ( Ptr(..), plusPtr, FunPtr(..) )
+import GHC.STRef
+import Data.Typeable
infixr 0 `par`, `pseq`
\end{code}
%************************************************************************
\begin{code}
-data ThreadId = ThreadId ThreadId#
+data ThreadId = ThreadId ThreadId# deriving( Typeable )
-- ToDo: data ThreadId = ThreadId (Weak ThreadId#)
-- But since ThreadId# is unlifted, the Weak type must use open
-- type variables.
useful when debugging or diagnosing the behaviour of a concurrent
program.
-NOTE: in GHC, if you have a 'ThreadId', you essentially have
+/Note/: in GHC, if you have a 'ThreadId', you essentially have
a pointer to the thread itself. This means the thread itself can\'t be
garbage collected until you drop the 'ThreadId'.
This misfeature will hopefully be corrected at a later date.
+
+/Note/: Hugs does not provide any operations on other threads;
+it defines 'ThreadId' as a synonym for ().
-}
--forkIO has now been hoisted out into the Concurrent library.
-{- | 'killThread' terminates the given thread (Note: 'killThread' is
-not implemented in Hugs). Any work already done by the thread isn\'t
+{- | 'killThread' terminates the given thread (GHC only).
+Any work already done by the thread isn\'t
lost: the computation is suspended until required by another thread.
The memory used by the thread will be garbage collected if it isn\'t
-referenced from anywhere. The 'killThread' function may be defined in
+referenced from anywhere. The 'killThread' function is defined in
terms of 'throwTo':
-> killThread = throwTo (AsyncException ThreadKilled)
+> killThread tid = throwTo tid (AsyncException ThreadKilled)
+
-}
killThread :: ThreadId -> IO ()
-killThread (ThreadId id) = IO $ \ s ->
- case (killThread# id (AsyncException ThreadKilled) s) of s1 -> (# s1, () #)
+killThread tid = throwTo tid (AsyncException ThreadKilled)
-{- | 'throwTo' raises an arbitrary exception in the target thread.
+{- | 'throwTo' raises an arbitrary exception in the target thread (GHC only).
'throwTo' does not return until the exception has been raised in the
target thread. The calling thread can thus be certain that the target
throwTo (ThreadId id) ex = IO $ \ s ->
case (killThread# id ex s) of s1 -> (# s1, () #)
--- | Returns the 'ThreadId' of the calling thread.
+-- | Returns the 'ThreadId' of the calling thread (GHC only).
myThreadId :: IO ThreadId
myThreadId = IO $ \s ->
case (myThreadId# s) of (# s1, id #) -> (# s1, ThreadId id #)
yield = IO $ \s ->
case (yield# s) of s1 -> (# s1, () #)
+{- | 'labelThread' stores a string as identifier for this thread if
+you built a RTS with debugging support. This identifier will be used in
+the debugging output to make distinction of different threads easier
+(otherwise you only have the thread state object\'s address in the heap).
+
+Other applications like the graphical Concurrent Haskell Debugger
+(<http://www.informatik.uni-kiel.de/~fhu/chd/>) may choose to overload
+'labelThread' for their purposes as well.
+-}
+
labelThread :: ThreadId -> String -> IO ()
labelThread (ThreadId t) str = IO $ \ s ->
let ps = packCString# str
adr = byteArrayContents# ps in
case (labelThread# t adr s) of s1 -> (# s1, () #)
-forkProcess :: IO Int
-forkProcess = IO $ \s -> case (forkProcess# s) of (# s1, id #) -> (# s1, (I# id) #)
-
-- Nota Bene: 'pseq' used to be 'seq'
-- but 'seq' is now defined in PrelGHC
--
par x y = case (par# x) of { _ -> lazy y }
\end{code}
+
+%************************************************************************
+%* *
+\subsection[stm]{Transactional heap operations}
+%* *
+%************************************************************************
+
+TVars are shared memory locations which support atomic memory
+transactions.
+
+\begin{code}
+newtype STM a = STM (State# RealWorld -> (# State# RealWorld, a #)) deriving( Typeable )
+
+unSTM :: STM a -> (State# RealWorld -> (# State# RealWorld, a #))
+unSTM (STM a) = a
+
+instance Functor STM where
+ fmap f x = x >>= (return . f)
+
+instance Monad STM where
+ {-# INLINE return #-}
+ {-# INLINE (>>) #-}
+ {-# INLINE (>>=) #-}
+ m >> k = thenSTM m k
+ return x = returnSTM x
+ m >>= k = bindSTM m k
+
+bindSTM :: STM a -> (a -> STM b) -> STM b
+bindSTM (STM m) k = STM ( \s ->
+ case m s of
+ (# new_s, a #) -> unSTM (k a) new_s
+ )
+
+thenSTM :: STM a -> STM b -> STM b
+thenSTM (STM m) k = STM ( \s ->
+ case m s of
+ (# new_s, a #) -> unSTM k new_s
+ )
+
+returnSTM :: a -> STM a
+returnSTM x = STM (\s -> (# s, x #))
+
+-- | Unsafely performs IO in the STM monad.
+unsafeIOToSTM :: IO a -> STM a
+unsafeIOToSTM (IO m) = STM m
+
+-- |Perform a series of STM actions atomically.
+atomically :: STM a -> IO a
+atomically (STM m) = IO (\s -> (atomically# m) s )
+
+-- |Retry execution of the current memory transaction because it has seen
+-- values in TVars which mean that it should not continue (e.g. the TVars
+-- represent a shared buffer that is now empty). The implementation may
+-- block the thread until one of the TVars that it has read from has been
+-- udpated.
+retry :: STM a
+retry = STM $ \s# -> retry# s#
+
+-- |Compose two alternative STM actions. If the first action completes without
+-- retrying then it forms the result of the orElse. Otherwise, if the first
+-- action retries, then the second action is tried in its place. If both actions
+-- retry then the orElse as a whole retries.
+orElse :: STM a -> STM a -> STM a
+orElse (STM m) e = STM $ \s -> catchRetry# m (unSTM e) s
+
+-- |Exception handling within STM actions.
+catchSTM :: STM a -> (Exception -> STM a) -> STM a
+catchSTM (STM m) k = STM $ \s -> catchSTM# m (\ex -> unSTM (k ex)) s
+
+data TVar a = TVar (TVar# RealWorld a) deriving( Typeable )
+
+instance Eq (TVar a) where
+ (TVar tvar1#) == (TVar tvar2#) = sameTVar# tvar1# tvar2#
+
+-- |Create a new TVar holding a value supplied
+newTVar :: a -> STM (TVar a)
+newTVar val = STM $ \s1# ->
+ case newTVar# val s1# of
+ (# s2#, tvar# #) -> (# s2#, TVar tvar# #)
+
+-- |Return the current value stored in a TVar
+readTVar :: TVar a -> STM a
+readTVar (TVar tvar#) = STM $ \s# -> readTVar# tvar# s#
+
+-- |Write the supplied value into a TVar
+writeTVar :: TVar a -> a -> STM ()
+writeTVar (TVar tvar#) val = STM $ \s1# ->
+ case writeTVar# tvar# val s1# of
+ s2# -> (# s2#, () #)
+
+\end{code}
+
%************************************************************************
%* *
\subsection[mvars]{M-Structures}
-- 'putMVar' will wait until it becomes empty.
--
-- If several threads are competing to fill the same 'MVar', one is
--- chosen to continue at random with the 'MVar' becomes empty.
+-- chosen to continue at random when the 'MVar' becomes empty.
putMVar :: MVar a -> a -> IO ()
putMVar (MVar mvar#) x = IO $ \ s# ->
case putMVar# mvar# x s# of
case isEmptyMVar# mv# s# of
(# s2#, flg #) -> (# s2#, not (flg ==# 0#) #)
--- |Add a finalizer to an 'MVar'. See "Foreign.ForeignPtr" and
+-- |Add a finalizer to an 'MVar' (GHC only). See "Foreign.ForeignPtr" and
-- "System.Mem.Weak" for more about finalizers.
addMVarFinalizer :: MVar a -> IO () -> IO ()
addMVarFinalizer (MVar m) finalizer =
%* *
%************************************************************************
-@threadWaitRead@ delays rescheduling of a thread until input on the
-specified file descriptor is available for reading (just like select).
-@threadWaitWrite@ is similar, but for writing on a file descriptor.
-
\begin{code}
--- |The 'threadDelay' operation will cause the current thread to
--- suspend for a given number of microseconds. Note that the resolution
--- used by the Haskell runtime system\'s internal timer together with the
--- fact that the thread may take some time to be rescheduled after the
--- time has expired, means that the accuracy is more like 1\/50 second.
-threadDelay :: Int -> IO ()
+#ifdef mingw32_HOST_OS
+
+-- Note: threadDelay, threadWaitRead and threadWaitWrite aren't really functional
+-- on Win32, but left in there because lib code (still) uses them (the manner
+-- in which they're used doesn't cause problems on a Win32 platform though.)
+
+asyncRead :: Int -> Int -> Int -> Ptr a -> IO (Int, Int)
+asyncRead (I# fd) (I# isSock) (I# len) (Ptr buf) =
+ IO $ \s -> case asyncRead# fd isSock len buf s of
+ (# s, len#, err# #) -> (# s, (I# len#, I# err#) #)
+
+asyncWrite :: Int -> Int -> Int -> Ptr a -> IO (Int, Int)
+asyncWrite (I# fd) (I# isSock) (I# len) (Ptr buf) =
+ IO $ \s -> case asyncWrite# fd isSock len buf s of
+ (# s, len#, err# #) -> (# s, (I# len#, I# err#) #)
+
+asyncDoProc :: FunPtr (Ptr a -> IO Int) -> Ptr a -> IO Int
+asyncDoProc (FunPtr proc) (Ptr param) =
+ -- the 'length' value is ignored; simplifies implementation of
+ -- the async*# primops to have them all return the same result.
+ IO $ \s -> case asyncDoProc# proc param s of
+ (# s, len#, err# #) -> (# s, I# err# #)
+
+-- to aid the use of these primops by the IO Handle implementation,
+-- provide the following convenience funs:
+
+-- this better be a pinned byte array!
+asyncReadBA :: Int -> Int -> Int -> Int -> MutableByteArray# RealWorld -> IO (Int,Int)
+asyncReadBA fd isSock len off bufB =
+ asyncRead fd isSock len ((Ptr (byteArrayContents# (unsafeCoerce# bufB))) `plusPtr` off)
+
+asyncWriteBA :: Int -> Int -> Int -> Int -> MutableByteArray# RealWorld -> IO (Int,Int)
+asyncWriteBA fd isSock len off bufB =
+ asyncWrite fd isSock len ((Ptr (byteArrayContents# (unsafeCoerce# bufB))) `plusPtr` off)
+
+#endif
+
+-- -----------------------------------------------------------------------------
+-- Thread IO API
-- | Block the current thread until data is available to read on the
--- given file descriptor.
-threadWaitRead :: Int -> IO ()
+-- given file descriptor (GHC only).
+threadWaitRead :: Fd -> IO ()
+threadWaitRead fd
+#ifndef mingw32_HOST_OS
+ | threaded = waitForReadEvent fd
+#endif
+ | otherwise = IO $ \s ->
+ case fromIntegral fd of { I# fd# ->
+ case waitRead# fd# s of { s -> (# s, () #)
+ }}
-- | Block the current thread until data can be written to the
--- given file descriptor.
-threadWaitWrite :: Int -> IO ()
-
-threadDelay (I# ms) = IO $ \s -> case delay# ms s of s -> (# s, () #)
-threadWaitRead (I# fd) = IO $ \s -> case waitRead# fd s of s -> (# s, () #)
-threadWaitWrite (I# fd) = IO $ \s -> case waitWrite# fd s of s -> (# s, () #)
+-- given file descriptor (GHC only).
+threadWaitWrite :: Fd -> IO ()
+threadWaitWrite fd
+#ifndef mingw32_HOST_OS
+ | threaded = waitForWriteEvent fd
+#endif
+ | otherwise = IO $ \s ->
+ case fromIntegral fd of { I# fd# ->
+ case waitWrite# fd# s of { s -> (# s, () #)
+ }}
+
+-- | Suspends the current thread for a given number of microseconds
+-- (GHC only).
+--
+-- Note that the resolution used by the Haskell runtime system's
+-- internal timer is 1\/50 second, and 'threadDelay' will round its
+-- argument up to the nearest multiple of this resolution.
+--
+-- There is no guarantee that the thread will be rescheduled promptly
+-- when the delay has expired, but the thread will never continue to
+-- run /earlier/ than specified.
+--
+threadDelay :: Int -> IO ()
+threadDelay time
+#ifndef mingw32_HOST_OS
+ | threaded = waitForDelayEvent time
+#else
+ | threaded = c_Sleep (fromIntegral (time `quot` 1000))
+#endif
+ | otherwise = IO $ \s ->
+ case fromIntegral time of { I# time# ->
+ case delay# time# s of { s -> (# s, () #)
+ }}
+
+-- On Windows, we just make a safe call to 'Sleep' to implement threadDelay.
+#ifdef mingw32_HOST_OS
+foreign import ccall safe "Sleep" c_Sleep :: CInt -> IO ()
+#endif
+
+foreign import ccall unsafe "rtsSupportsBoundThreads" threaded :: Bool
+
+-- ----------------------------------------------------------------------------
+-- Threaded RTS implementation of threadWaitRead, threadWaitWrite, threadDelay
+
+-- In the threaded RTS, we employ a single IO Manager thread to wait
+-- for all outstanding IO requests (threadWaitRead,threadWaitWrite)
+-- and delays (threadDelay).
+--
+-- We can do this because in the threaded RTS the IO Manager can make
+-- a non-blocking call to select(), so we don't have to do select() in
+-- the scheduler as we have to in the non-threaded RTS. We get performance
+-- benefits from doing it this way, because we only have to restart the select()
+-- when a new request arrives, rather than doing one select() each time
+-- around the scheduler loop. Furthermore, the scheduler can be simplified
+-- by not having to check for completed IO requests.
+
+-- Issues, possible problems:
+--
+-- - we might want bound threads to just do the blocking
+-- operation rather than communicating with the IO manager
+-- thread. This would prevent simgle-threaded programs which do
+-- IO from requiring multiple OS threads. However, it would also
+-- prevent bound threads waiting on IO from being killed or sent
+-- exceptions.
+--
+-- - Apprently exec() doesn't work on Linux in a multithreaded program.
+-- I couldn't repeat this.
+--
+-- - How do we handle signal delivery in the multithreaded RTS?
+--
+-- - forkProcess will kill the IO manager thread. Let's just
+-- hope we don't need to do any blocking IO between fork & exec.
+
+#ifndef mingw32_HOST_OS
+
+data IOReq
+ = Read {-# UNPACK #-} !Fd {-# UNPACK #-} !(MVar ())
+ | Write {-# UNPACK #-} !Fd {-# UNPACK #-} !(MVar ())
+
+data DelayReq
+ = Delay {-# UNPACK #-} !Int {-# UNPACK #-} !(MVar ())
+
+pendingEvents :: IORef [IOReq]
+pendingDelays :: IORef [DelayReq]
+ -- could use a strict list or array here
+{-# NOINLINE pendingEvents #-}
+{-# NOINLINE pendingDelays #-}
+(pendingEvents,pendingDelays) = unsafePerformIO $ do
+ startIOServiceThread
+ reqs <- newIORef []
+ dels <- newIORef []
+ return (reqs, dels)
+ -- the first time we schedule an IO request, the service thread
+ -- will be created (cool, huh?)
+
+startIOServiceThread :: IO ()
+startIOServiceThread = do
+ allocaArray 2 $ \fds -> do
+ throwErrnoIfMinus1 "startIOServiceThread" (c_pipe fds)
+ rd_end <- peekElemOff fds 0
+ wr_end <- peekElemOff fds 1
+ writeIORef stick (fromIntegral wr_end)
+ quickForkIO $ do
+ allocaBytes sizeofFdSet $ \readfds -> do
+ allocaBytes sizeofFdSet $ \writefds -> do
+ allocaBytes sizeofTimeVal $ \timeval -> do
+ service_loop (fromIntegral rd_end) readfds writefds timeval [] []
+ return ()
+
+-- XXX: move real forkIO here from Control.Concurrent?
+quickForkIO action = IO $ \s ->
+ case (fork# action s) of (# s1, id #) -> (# s1, ThreadId id #)
+
+service_loop
+ :: Fd -- listen to this for wakeup calls
+ -> Ptr CFdSet
+ -> Ptr CFdSet
+ -> Ptr CTimeVal
+ -> [IOReq]
+ -> [DelayReq]
+ -> IO ()
+service_loop wakeup readfds writefds ptimeval old_reqs old_delays = do
+
+ -- pick up new IO requests
+ new_reqs <- atomicModifyIORef pendingEvents (\a -> ([],a))
+ let reqs = new_reqs ++ old_reqs
+
+ -- pick up new delay requests
+ new_delays <- atomicModifyIORef pendingDelays (\a -> ([],a))
+ let delays = foldr insertDelay old_delays new_delays
+
+ -- build the FDSets for select()
+ fdZero readfds
+ fdZero writefds
+ fdSet wakeup readfds
+ maxfd <- buildFdSets 0 readfds writefds reqs
+
+ -- check the current time and wake up any thread in threadDelay whose
+ -- timeout has expired. Also find the timeout value for the select() call.
+ now <- getTicksOfDay
+ (delays', timeout) <- getDelay now ptimeval delays
+
+ -- perform the select()
+ let do_select = do
+ res <- c_select ((max wakeup maxfd)+1) readfds writefds
+ nullPtr timeout
+ if (res == -1)
+ then do
+ err <- getErrno
+ if err == eINTR
+ then do_select
+ else return res
+ else
+ return res
+ res <- do_select
+ -- ToDo: check result
+
+ b <- takeMVar prodding
+ if b then alloca $ \p -> do c_read (fromIntegral wakeup) p 1; return ()
+ else return ()
+ putMVar prodding False
+
+ reqs' <- completeRequests reqs readfds writefds []
+ service_loop wakeup readfds writefds ptimeval reqs' delays'
+
+stick :: IORef Fd
+{-# NOINLINE stick #-}
+stick = unsafePerformIO (newIORef 0)
+
+prodding :: MVar Bool
+{-# NOINLINE prodding #-}
+prodding = unsafePerformIO (newMVar False)
+
+prodServiceThread :: IO ()
+prodServiceThread = do
+ b <- takeMVar prodding
+ if (not b)
+ then do fd <- readIORef stick
+ with 42 $ \pbuf -> do c_write (fromIntegral fd) pbuf 1; return ()
+ else return ()
+ putMVar prodding True
+
+-- -----------------------------------------------------------------------------
+-- IO requests
+
+buildFdSets maxfd readfds writefds [] = return maxfd
+buildFdSets maxfd readfds writefds (Read fd m : reqs) = do
+ fdSet fd readfds
+ buildFdSets (max maxfd fd) readfds writefds reqs
+buildFdSets maxfd readfds writefds (Write fd m : reqs) = do
+ fdSet fd writefds
+ buildFdSets (max maxfd fd) readfds writefds reqs
+
+completeRequests [] _ _ reqs' = return reqs'
+completeRequests (Read fd m : reqs) readfds writefds reqs' = do
+ b <- fdIsSet fd readfds
+ if b /= 0
+ then do putMVar m (); completeRequests reqs readfds writefds reqs'
+ else completeRequests reqs readfds writefds (Read fd m : reqs')
+completeRequests (Write fd m : reqs) readfds writefds reqs' = do
+ b <- fdIsSet fd writefds
+ if b /= 0
+ then do putMVar m (); completeRequests reqs readfds writefds reqs'
+ else completeRequests reqs readfds writefds (Write fd m : reqs')
+
+waitForReadEvent :: Fd -> IO ()
+waitForReadEvent fd = do
+ m <- newEmptyMVar
+ atomicModifyIORef pendingEvents (\xs -> (Read fd m : xs, ()))
+ prodServiceThread
+ takeMVar m
+
+waitForWriteEvent :: Fd -> IO ()
+waitForWriteEvent fd = do
+ m <- newEmptyMVar
+ atomicModifyIORef pendingEvents (\xs -> (Write fd m : xs, ()))
+ prodServiceThread
+ takeMVar m
+
+-- XXX: move into GHC.IOBase from Data.IORef?
+atomicModifyIORef :: IORef a -> (a -> (a,b)) -> IO b
+atomicModifyIORef (IORef (STRef r#)) f = IO $ \s -> atomicModifyMutVar# r# f s
+
+-- -----------------------------------------------------------------------------
+-- Delays
+
+waitForDelayEvent :: Int -> IO ()
+waitForDelayEvent usecs = do
+ m <- newEmptyMVar
+ now <- getTicksOfDay
+ let target = now + usecs `quot` tick_usecs
+ atomicModifyIORef pendingDelays (\xs -> (Delay target m : xs, ()))
+ prodServiceThread
+ takeMVar m
+
+-- Walk the queue of pending delays, waking up any that have passed
+-- and return the smallest delay to wait for. The queue of pending
+-- delays is kept ordered.
+getDelay :: Ticks -> Ptr CTimeVal -> [DelayReq] -> IO ([DelayReq], Ptr CTimeVal)
+getDelay now ptimeval [] = return ([],nullPtr)
+getDelay now ptimeval all@(Delay time m : rest)
+ | now >= time = do
+ putMVar m ()
+ getDelay now ptimeval rest
+ | otherwise = do
+ setTimevalTicks ptimeval (time - now)
+ return (all,ptimeval)
+
+insertDelay :: DelayReq -> [DelayReq] -> [DelayReq]
+insertDelay d@(Delay time m) [] = [d]
+insertDelay d1@(Delay time m) ds@(d2@(Delay time' m') : rest)
+ | time <= time' = d1 : ds
+ | otherwise = d2 : insertDelay d1 rest
+
+type Ticks = Int
+tick_freq = 50 :: Ticks -- accuracy of threadDelay (ticks per sec)
+tick_usecs = 1000000 `quot` tick_freq :: Int
+
+newtype CTimeVal = CTimeVal ()
+
+foreign import ccall unsafe "sizeofTimeVal"
+ sizeofTimeVal :: Int
+
+foreign import ccall unsafe "getTicksOfDay"
+ getTicksOfDay :: IO Ticks
+
+foreign import ccall unsafe "setTimevalTicks"
+ setTimevalTicks :: Ptr CTimeVal -> Ticks -> IO ()
+
+-- ----------------------------------------------------------------------------
+-- select() interface
+
+-- ToDo: move to System.Posix.Internals?
+
+newtype CFdSet = CFdSet ()
+
+foreign import ccall safe "select"
+ c_select :: Fd -> Ptr CFdSet -> Ptr CFdSet -> Ptr CFdSet -> Ptr CTimeVal
+ -> IO CInt
+
+foreign import ccall unsafe "hsFD_CLR"
+ fdClr :: Fd -> Ptr CFdSet -> IO ()
+
+foreign import ccall unsafe "hsFD_ISSET"
+ fdIsSet :: Fd -> Ptr CFdSet -> IO CInt
+
+foreign import ccall unsafe "hsFD_SET"
+ fdSet :: Fd -> Ptr CFdSet -> IO ()
+
+foreign import ccall unsafe "hsFD_ZERO"
+ fdZero :: Ptr CFdSet -> IO ()
+
+foreign import ccall unsafe "sizeof_fd_set"
+ sizeofFdSet :: Int
+
+#endif
\end{code}
projects / ghc-base.git / blobdiff