----------------------------------------------------------------------------- -- | -- Module : System.Exit -- Copyright : (c) The University of Glasgow 2001 -- License : BSD-style (see the file libraries/base/LICENSE) -- -- Maintainer : libraries@haskell.org -- Stability : provisional -- Portability : portable -- -- Exiting the program. -- -----------------------------------------------------------------------------
module System.Exit ( ExitCode(ExitSuccess,ExitFailure) , exitWith -- :: ExitCode -> IO a , exitFailure -- :: IO a ) where import Prelude import Hugs.Prelude import Hugs.Exception -- --------------------------------------------------------------------------- -- exitWith -- | Computation 'exitWith' @code@ throws 'ExitException' @code@. -- Normally this terminates the program, returning @code@ to the -- program's caller. Before the program terminates, any open or -- semi-closed handles are first closed. -- -- A program that fails in any other way is treated as if it had -- called 'exitFailure'. -- A program that terminates successfully without calling 'exitWith' -- explicitly is treated as it it had called 'exitWith' 'ExitSuccess'. -- -- As an 'ExitException' is not an 'IOError', 'exitWith' bypasses -- the error handling in the 'IO' monad and cannot be intercepted by -- 'catch' from the "Prelude". However it is an 'Exception', and can -- be caught using the functions of "Control.Exception". This means -- that cleanup computations added with 'Control.Exception.bracket' -- (from "Control.Exception") are also executed properly on 'exitWith'. exitWith :: ExitCode -> IO a exitWith ExitSuccess = throwIO (ExitException ExitSuccess) exitWith code@(ExitFailure n) | n /= 0 = throwIO (ExitException code) -- | The computation 'exitFailure' is equivalent to -- 'exitWith' @(@'ExitFailure' /exitfail/@)@, -- where /exitfail/ is implementation-dependent. exitFailure :: IO a exitFailure = exitWith (ExitFailure 1)
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