Handle

Haskell defines operations to read and write characters from and to files, represented by values of type Handle. Each value of this type is a handle: a record used by the Haskell run-time system to manage I/O with file system objects. A handle has at least the following properties: * whether it manages input or output or both; * whether it is open, closed or semi-closed; * whether the object is seekable; * whether buffering is disabled, or enabled on a line or block basis; * a buffer (whose length may be zero). Most handles will also have a current I/O position indicating the next input or output operation will occur. A handle is readable if it manages only input or both input and output; likewise, it is writable if it manages only output or both input and output. A handle is open when first allocated. Once it is closed it can no longer be used for either input or output, though an implementation cannot re-use its storage while references remain to it. Handles are in the Show and Eq classes. The string produced by showing a handle is system dependent; it should include enough information to identify the handle for debugging. A handle is equal according to == only to itself; no attempt is made to compare the internal state of different handles for equality.

handle :: (Exception -> IO a) -> IO a -> IO a

base Control.OldException

A version of catch with the arguments swapped around; useful in situations > do handle (\e -> exitWith (ExitFailure 1)) $ > ...

handle :: Exception e => (e -> IO a) -> IO a -> IO a

base Control.Exception.Base, base Control.Exception

A version of catch with the arguments swapped around; useful in situations > do handle (\NonTermination -> exitWith (ExitFailure 1)) $ > ...

handleJust :: (Exception -> Maybe b) -> (b -> IO a) -> IO a -> IO a

base Control.OldException

A version of catchJust with the arguments swapped around (see handle).

handleJust :: Exception e => (e -> Maybe b) -> (b -> IO a) -> IO a -> IO a

base Control.Exception.Base, base Control.Exception

A version of catchJust with the arguments swapped around (see handle).

data HandlePosn

base System.IO, base GHC.IO.Handle

Handler :: (e -> IO a) -> Handler a

base Control.Exception

data Handler a

base Control.Exception

You need this when using catches.

module GHC.IO.Handle

base GHC.IO.Handle

External API for GHC's Handle implementation

handle :: Handle -> String -> IO ()

QuickCheck Test.QuickCheck.Text

handleErrors :: (MonadCGI m, MonadCatchIO m) => m CGIResult -> m CGIResult

cgi Network.CGI

Catches any exception thrown by the given CGI action, returns an error page with a 500 Internal Server Error, showing the exception information, and logs the error. Typical usage: > cgiMain :: CGI CGIResult > cgiMain = ... > > main :: IO () > main = runCGI (handleErrors cgiMain)

handleExceptionCGI :: (MonadCGI m, MonadCatchIO m) => m a -> (SomeException -> m a) -> m a

cgi Network.CGI.Monad, cgi Network.CGI

Deprecated version of catchCGI. Use catchCGI instead.

type HandlePosition = Integer

base GHC.IO.Handle

HandlePosn :: Handle -> HandlePosition -> HandlePosn

base GHC.IO.Handle

data Handler

unix System.Posix.Signals

The actions to perform when a signal is received.

type HandlerFun = ForeignPtr Word8 -> IO ()

base GHC.Conc.Signal, base GHC.Conc