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fix silly mistake in hGetBufSome (#4895)
[ghc-base.git]
/
Control
/
Concurrent.hs
diff --git
a/Control/Concurrent.hs
b/Control/Concurrent.hs
index
bd05cdc
..
d1b6875
100644
(file)
--- a/
Control/Concurrent.hs
+++ b/
Control/Concurrent.hs
@@
-422,18
+422,24
@@
performance loss due to the use of bound threads. A program that
doesn't need it's main thread to be bound and makes /heavy/ use of concurrency
(e.g. a web server), might want to wrap it's @main@ action in
@runInUnboundThread@.
doesn't need it's main thread to be bound and makes /heavy/ use of concurrency
(e.g. a web server), might want to wrap it's @main@ action in
@runInUnboundThread@.
+
+Note that exceptions which are thrown to the current thread are thrown in turn
+to the thread that is executing the given computation. This ensures there's
+always a way of killing the forked thread.
-}
runInUnboundThread :: IO a -> IO a
runInUnboundThread action = do
-}
runInUnboundThread :: IO a -> IO a
runInUnboundThread action = do
- bound <- isCurrentThreadBound
- if bound
- then do
- mv <- newEmptyMVar
- _ <- mask $ \restore -> forkIO $
- Exception.try (restore action) >>= putMVar mv
- takeMVar mv >>= unsafeResult
- else action
+ bound <- isCurrentThreadBound
+ if bound
+ then do
+ mv <- newEmptyMVar
+ mask $ \restore -> do
+ tid <- forkIO $ Exception.try (restore action) >>= putMVar mv
+ let wait = takeMVar mv `Exception.catch` \(e :: SomeException) ->
+ Exception.throwTo tid e >> wait
+ wait >>= unsafeResult
+ else action
unsafeResult :: Either SomeException a -> IO a
unsafeResult = either Exception.throwIO return
unsafeResult :: Either SomeException a -> IO a
unsafeResult = either Exception.throwIO return
@@
-445,6
+451,11
@@
unsafeResult = either Exception.throwIO return
-- | Block the current thread until data is available to read on the
-- given file descriptor (GHC only).
-- | Block the current thread until data is available to read on the
-- given file descriptor (GHC only).
+--
+-- This will throw an 'IOError' if the file descriptor was closed
+-- while this thread was blocked. To safely close a file descriptor
+-- that has been used with 'threadWaitRead', use
+-- 'GHC.Conc.closeFdWith'.
threadWaitRead :: Fd -> IO ()
threadWaitRead fd
#ifdef mingw32_HOST_OS
threadWaitRead :: Fd -> IO ()
threadWaitRead fd
#ifdef mingw32_HOST_OS
@@
-465,6
+476,11
@@
threadWaitRead fd
-- | Block the current thread until data can be written to the
-- given file descriptor (GHC only).
-- | Block the current thread until data can be written to the
-- given file descriptor (GHC only).
+--
+-- This will throw an 'IOError' if the file descriptor was closed
+-- while this thread was blocked. To safely close a file descriptor
+-- that has been used with 'threadWaitWrite', use
+-- 'GHC.Conc.closeFdWith'.
threadWaitWrite :: Fd -> IO ()
threadWaitWrite fd
#ifdef mingw32_HOST_OS
threadWaitWrite :: Fd -> IO ()
threadWaitWrite fd
#ifdef mingw32_HOST_OS
@@
-489,7
+505,7
@@
withThread io = do
waitFd :: Fd -> CInt -> IO ()
waitFd fd write = do
throwErrnoIfMinus1_ "fdReady" $
waitFd :: Fd -> CInt -> IO ()
waitFd fd write = do
throwErrnoIfMinus1_ "fdReady" $
- fdReady (fromIntegral fd) write (fromIntegral iNFINITE) 0
+ fdReady (fromIntegral fd) write iNFINITE 0
iNFINITE :: CInt
iNFINITE = 0xFFFFFFFF -- urgh
iNFINITE :: CInt
iNFINITE = 0xFFFFFFFF -- urgh