| Copyright | (c) The University of Glasgow 1994-2002 |
|---|---|
| License | see libraries/base/LICENSE |
| Maintainer | cvs-ghc@haskell.org |
| Stability | internal |
| Portability | non-portable (GHC extensions) |
| Safe Haskell | Trustworthy |
| Language | Haskell2010 |
GHC.Conc.IO
Contents
Description
Basic concurrency stuff.
Synopsis
- ensureIOManagerIsRunning :: IO ()
- ioManagerCapabilitiesChanged :: IO ()
- threadDelay :: Int -> IO ()
- registerDelay :: Int -> IO (TVar Bool)
- threadWaitRead :: Fd -> IO ()
- threadWaitWrite :: Fd -> IO ()
- threadWaitReadSTM :: Fd -> IO (STM (), IO ())
- threadWaitWriteSTM :: Fd -> IO (STM (), IO ())
- closeFdWith :: (Fd -> IO ()) -> Fd -> IO ()
Documentation
ensureIOManagerIsRunning :: IO () #
ioManagerCapabilitiesChanged :: IO () #
Waiting
threadDelay :: Int -> IO () #
Suspends the current thread for a given number of microseconds (GHC only).
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.
registerDelay :: Int -> IO (TVar Bool) #
Switch the value of returned TVar from initial value False to True
after a given number of microseconds. The caveats associated with
threadDelay also apply.
threadWaitRead :: Fd -> IO () #
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 closeFdWith.
threadWaitWrite :: Fd -> IO () #
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 closeFdWith.
threadWaitReadSTM :: Fd -> IO (STM (), IO ()) #
Returns an STM action that can be used to wait for data to read from a file descriptor. The second returned value is an IO action that can be used to deregister interest in the file descriptor.
threadWaitWriteSTM :: Fd -> IO (STM (), IO ()) #
Returns an STM action that can be used to wait until data can be written to a file descriptor. The second returned value is an IO action that can be used to deregister interest in the file descriptor.
Arguments
| :: (Fd -> IO ()) | Low-level action that performs the real close. |
| -> Fd | File descriptor to close. |
| -> IO () |
Close a file descriptor in a concurrency-safe way (GHC only). If
you are using threadWaitRead or threadWaitWrite to perform
blocking I/O, you must use this function to close file
descriptors, or blocked threads may not be woken.
Any threads that are blocked on the file descriptor via
threadWaitRead or threadWaitWrite will be unblocked by having
IO exceptions thrown.