System.Exit

Documentation

data ExitCode

Defines the exit codes that a program can return.

Constructors

ExitSuccess

indicates successful termination;

ExitFailure Int

indicates program failure with an exit code. The exact interpretation of the code is operating-system dependent. In particular, some values may be prohibited (e.g. 0 on a POSIX-compliant system).

Instances

Eq ExitCode

Defined in GHC.IO.Exception

Methods

(==) :: ExitCode -> ExitCode -> Bool

(/=) :: ExitCode -> ExitCode -> Bool

Ord ExitCode

Defined in GHC.IO.Exception

Methods

compare :: ExitCode -> ExitCode -> Ordering

(<) :: ExitCode -> ExitCode -> Bool

(<=) :: ExitCode -> ExitCode -> Bool

(>) :: ExitCode -> ExitCode -> Bool

(>=) :: ExitCode -> ExitCode -> Bool

max :: ExitCode -> ExitCode -> ExitCode

min :: ExitCode -> ExitCode -> ExitCode

Read ExitCode

Defined in GHC.IO.Exception

Methods

readsPrec :: Int -> ReadS ExitCode

readList :: ReadS [ExitCode]

readPrec :: ReadPrec ExitCode

readListPrec :: ReadPrec [ExitCode]

Show ExitCode

Defined in GHC.IO.Exception

Methods

showsPrec :: Int -> ExitCode -> ShowS

show :: ExitCode -> String

showList :: [ExitCode] -> ShowS

Generic ExitCode

Defined in GHC.IO.Exception

Associated Types

type Rep ExitCode :: Type -> Type

Methods

from :: ExitCode -> Rep ExitCode x

to :: Rep ExitCode x -> ExitCode

Exception ExitCode

Since: base-4.1.0.0

Defined in GHC.IO.Exception

Methods

toException :: ExitCode -> SomeException

fromException :: SomeException -> Maybe ExitCode

displayException :: ExitCode -> String

type Rep ExitCode

Defined in GHC.IO.Exception

type Rep ExitCode = D1 (MetaData "ExitCode" "GHC.IO.Exception" "base" False) (C1 (MetaCons "ExitSuccess" PrefixI False) (U1 :: Type -> Type) :+: C1 (MetaCons "ExitFailure" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 Int)))

exitWith :: ExitCode -> IO a

Computation exitWith code terminates the program, returning code to the program's caller. The caller may interpret the return code as it wishes, but the program should return ExitSuccess to mean normal completion, and ExitFailure n to mean that the program encountered a problem from which it could not recover. The value exitFailure is equal to exitWith (ExitFailure exitfail), where exitfail is implementation-dependent. exitWith bypasses the error handling in the I/O monad and cannot be intercepted by catch from the Prelude.

exitFailure :: IO a

The computation exitFailure is equivalent to exitWith (ExitFailure exitfail), where exitfail is implementation-dependent.

exitSuccess :: IO a

The computation exitSuccess is equivalent to exitWith ExitSuccess, It terminates the program successfully.