System.GPIO.Linux.Sysfs.IO

The actual Linux sysfs implementation. This implementation will only function properly on Linux systems with a sysfs subsystem, obviously.

SysfsIOT transformer

newtype SysfsIOT m a

An instance of MonadSysfs which runs MonadSysfs operations in IO. This instance must be run on an actual Linux sysfs GPIO filesystem and will fail in any other environment.

Interactions with threads

Some parts of this implementation use the Haskell C FFI, and may block on C I/O operations. (Specifically, pollFile will block in the C FFI until its event is triggered.) When using this implementation with GHC, you should compile your program with the -threaded option, so that threads performing these blocking operations do not block other Haskell threads in the system.

Note that the C FFI bits in this implementation are marked as interruptible, so that, on versions of GHC later than 7.8.1, functions such as throwTo will work properly when targeting a Haskell thread that uses this implementation.

(On Haskell implementations other than GHC, the threading implications are unknown; see the implementation's notes on how its threading system interacts with the C FFI.)

Constructors

SysfsIOT

Fields

• runSysfsIOT :: m a

Instances

MonadTrans SysfsIOT

Methods

lift :: Monad m => m a -> SysfsIOT m a

MonadRWS r w s m => MonadRWS r w s (SysfsIOT m)

MonadError e m => MonadError e (SysfsIOT m)

Methods

throwError :: e -> SysfsIOT m a

catchError :: SysfsIOT m a -> (e -> SysfsIOT m a) -> SysfsIOT m a

MonadReader r m => MonadReader r (SysfsIOT m)

Methods

ask :: SysfsIOT m r

local :: (r -> r) -> SysfsIOT m a -> SysfsIOT m a

reader :: (r -> a) -> SysfsIOT m a

MonadState s m => MonadState s (SysfsIOT m)

Methods

get :: SysfsIOT m s

put :: s -> SysfsIOT m ()

state :: (s -> (a, s)) -> SysfsIOT m a

MonadWriter w m => MonadWriter w (SysfsIOT m)

Methods

writer :: (a, w) -> SysfsIOT m a

tell :: w -> SysfsIOT m ()

listen :: SysfsIOT m a -> SysfsIOT m (a, w)

pass :: SysfsIOT m (a, w -> w) -> SysfsIOT m a

Monad m => Monad (SysfsIOT m)

Methods

(>>=) :: SysfsIOT m a -> (a -> SysfsIOT m b) -> SysfsIOT m b

(>>) :: SysfsIOT m a -> SysfsIOT m b -> SysfsIOT m b

return :: a -> SysfsIOT m a

fail :: String -> SysfsIOT m a

Functor m => Functor (SysfsIOT m)

Methods

fmap :: (a -> b) -> SysfsIOT m a -> SysfsIOT m b

(<$) :: a -> SysfsIOT m b -> SysfsIOT m a

MonadFix m => MonadFix (SysfsIOT m)

Methods

mfix :: (a -> SysfsIOT m a) -> SysfsIOT m a

Applicative m => Applicative (SysfsIOT m)

Methods

pure :: a -> SysfsIOT m a

(<*>) :: SysfsIOT m (a -> b) -> SysfsIOT m a -> SysfsIOT m b

(*>) :: SysfsIOT m a -> SysfsIOT m b -> SysfsIOT m b

(<*) :: SysfsIOT m a -> SysfsIOT m b -> SysfsIOT m a

MonadIO m => MonadIO (SysfsIOT m)

Methods

liftIO :: IO a -> SysfsIOT m a

Alternative m => Alternative (SysfsIOT m)

Methods

empty :: SysfsIOT m a

(<|>) :: SysfsIOT m a -> SysfsIOT m a -> SysfsIOT m a

some :: SysfsIOT m a -> SysfsIOT m [a]

many :: SysfsIOT m a -> SysfsIOT m [a]

MonadPlus m => MonadPlus (SysfsIOT m)

Methods

mzero :: SysfsIOT m a

mplus :: SysfsIOT m a -> SysfsIOT m a -> SysfsIOT m a

MonadThrow m => MonadThrow (SysfsIOT m)

Methods

throwM :: Exception e => e -> SysfsIOT m a

MonadCatch m => MonadCatch (SysfsIOT m)

Methods

catch :: Exception e => SysfsIOT m a -> (e -> SysfsIOT m a) -> SysfsIOT m a

MonadMask m => MonadMask (SysfsIOT m)

Methods

mask :: ((forall a. SysfsIOT m a -> SysfsIOT m a) -> SysfsIOT m b) -> SysfsIOT m b

uninterruptibleMask :: ((forall a. SysfsIOT m a -> SysfsIOT m a) -> SysfsIOT m b) -> SysfsIOT m b

MonadCont m => MonadCont (SysfsIOT m)

Methods

callCC :: ((a -> SysfsIOT m b) -> SysfsIOT m a) -> SysfsIOT m a

(MonadIO m, MonadThrow m) => MonadSysfs (SysfsIOT m)

Methods

doesDirectoryExist :: FilePath -> SysfsIOT m Bool

doesFileExist :: FilePath -> SysfsIOT m Bool

getDirectoryContents :: FilePath -> SysfsIOT m [FilePath]

readFile :: FilePath -> SysfsIOT m ByteString

writeFile :: FilePath -> ByteString -> SysfsIOT m ()

unlockedWriteFile :: FilePath -> ByteString -> SysfsIOT m ()

pollFile :: FilePath -> Int -> SysfsIOT m CInt