    {-# LANGUAGE CPP, ForeignFunctionInterface #-}
    #if __GLASGOW_HASKELL__ >= 709
    {-# LANGUAGE Safe #-}
    #else
    {-# LANGUAGE Trustworthy #-}
    #endif
    {-# LANGUAGE InterruptibleFFI #-}

    -----------------------------------------------------------------------------
    -- |
    -- Module      :  System.Process
    -- Copyright   :  (c) The University of Glasgow 2004-2008
    -- License     :  BSD-style (see the file libraries/base/LICENSE)
    --
    -- Maintainer  :  libraries@haskell.org
    -- Stability   :  experimental
    -- Portability :  non-portable (requires concurrency)
    --
    -- Operations for creating and interacting with sub-processes.
    --
    -----------------------------------------------------------------------------

    -- ToDo:
    --      * Flag to control whether exiting the parent also kills the child.

    module System.Process (
        -- * Running sub-processes
        createProcess,
        createProcess_,
        shell, proc,
        CreateProcess(..),
        CmdSpec(..),
        StdStream(..),
        ProcessHandle,

        -- ** Simpler functions for common tasks
        callProcess,
        callCommand,
        spawnProcess,
        spawnCommand,
        readCreateProcess,
        readProcess,
        readCreateProcessWithExitCode,
        readProcessWithExitCode,
        withCreateProcess,
        cleanupProcess,

        -- ** Related utilities
        showCommandForUser,
        Pid,
        getPid,
        getCurrentPid,

        -- ** Control-C handling on Unix
        -- $ctlc-handling

        -- * Process completion
        -- ** Notes about @exec@ on Windows
        -- $exec-on-windows
        waitForProcess,
        getProcessExitCode,
        terminateProcess,
        interruptProcessGroupOf,

        -- * Interprocess communication
        createPipe,
        createPipeFd,

        -- * Old deprecated functions
        -- | These functions pre-date 'createProcess' which is much more
        -- flexible.
        runProcess,
        runCommand,
        runInteractiveProcess,
        runInteractiveCommand,
        system,
        rawSystem,
        ) where

    import Prelude hiding (mapM)

    import System.Process.Internals

    import Control.Concurrent
    import Control.DeepSeq (rnf)
    import Control.Exception (SomeException, mask, allowInterrupt, bracket, try, throwIO)
    import qualified Control.Exception as C
    import Control.Monad
    import Data.Maybe
    import Foreign
    import Foreign.C
    import System.Exit      ( ExitCode(..) )
    import System.IO
    import System.IO.Error (mkIOError, ioeSetErrorString)

    #if defined(WINDOWS)
    import System.Win32.Process (getProcessId, getCurrentProcessId, ProcessId)
    #else
    import System.Posix.Process (getProcessID)
    import System.Posix.Types (CPid (..))
    #endif

    import GHC.IO.Exception ( ioException, IOErrorType(..), IOException(..) )

    -- | The platform specific type for a process identifier.
    --
    -- This is always an integral type. Width and signedness are platform specific.
    --
    -- @since 1.6.3.0
    #if defined(WINDOWS)
    type Pid = ProcessId
    #else
    type Pid = CPid
    #endif

    -- ----------------------------------------------------------------------------
    -- createProcess

    -- | Construct a 'CreateProcess' record for passing to 'createProcess',
    -- representing a raw command with arguments.
    --
    -- See 'RawCommand' for precise semantics of the specified @FilePath@.
    proc :: FilePath -> [String] -> CreateProcess
    proc :: String -> [String] -> CreateProcess
    proc String
    cmd [String]
    args = CreateProcess { cmdspec :: CmdSpec
    cmdspec = String -> [String] -> CmdSpec
    RawCommand String
    cmd [String]
    args,
                                    cwd :: Maybe String
    cwd = Maybe String
    forall a. Maybe a
    Nothing,
                                    env :: Maybe [(String, String)]
    env = Maybe [(String, String)]
    forall a. Maybe a
    Nothing,
                                    std_in :: StdStream
    std_in = StdStream
    Inherit,
                                    std_out :: StdStream
    std_out = StdStream
    Inherit,
                                    std_err :: StdStream
    std_err = StdStream
    Inherit,
                                    close_fds :: Bool
    close_fds = Bool
    False,
                                    create_group :: Bool
    create_group = Bool
    False,
                                    delegate_ctlc :: Bool
    delegate_ctlc = Bool
    False,
                                    detach_console :: Bool
    detach_console = Bool
    False,
                                    create_new_console :: Bool
    create_new_console = Bool
    False,
                                    new_session :: Bool
    new_session = Bool
    False,
                                    child_group :: Maybe GroupID
    child_group = Maybe GroupID
    forall a. Maybe a
    Nothing,
                                    child_user :: Maybe UserID
    child_user = Maybe UserID
    forall a. Maybe a
    Nothing,
                                    use_process_jobs :: Bool
    use_process_jobs = Bool
    False }

    -- | Construct a 'CreateProcess' record for passing to 'createProcess',
    -- representing a command to be passed to the shell.
    shell :: String -> CreateProcess
    shell :: String -> CreateProcess
    shell String
    str = CreateProcess { cmdspec :: CmdSpec
    cmdspec = String -> CmdSpec
    ShellCommand String
    str,
                                cwd :: Maybe String
    cwd = Maybe String
    forall a. Maybe a
    Nothing,
                                env :: Maybe [(String, String)]
    env = Maybe [(String, String)]
    forall a. Maybe a
    Nothing,
                                std_in :: StdStream
    std_in = StdStream
    Inherit,
                                std_out :: StdStream
    std_out = StdStream
    Inherit,
                                std_err :: StdStream
    std_err = StdStream
    Inherit,
                                close_fds :: Bool
    close_fds = Bool
    False,
                                create_group :: Bool
    create_group = Bool
    False,
                                delegate_ctlc :: Bool
    delegate_ctlc = Bool
    False,
                                detach_console :: Bool
    detach_console = Bool
    False,
                                create_new_console :: Bool
    create_new_console = Bool
    False,
                                new_session :: Bool
    new_session = Bool
    False,
                                child_group :: Maybe GroupID
    child_group = Maybe GroupID
    forall a. Maybe a
    Nothing,
                                child_user :: Maybe UserID
    child_user = Maybe UserID
    forall a. Maybe a
    Nothing,
                                use_process_jobs :: Bool
    use_process_jobs = Bool
    False }

    {- |
    This is the most general way to spawn an external process.  The
    process can be a command line to be executed by a shell or a raw command
    with a list of arguments.  The stdin, stdout, and stderr streams of
    the new process may individually be attached to new pipes, to existing
    'Handle's, or just inherited from the parent (the default.)

    The details of how to create the process are passed in the
    'CreateProcess' record.  To make it easier to construct a
    'CreateProcess', the functions 'proc' and 'shell' are supplied that
    fill in the fields with default values which can be overriden as
    needed.

    'createProcess' returns @(/mb_stdin_hdl/, /mb_stdout_hdl/, /mb_stderr_hdl/, /ph/)@,
    where

     * if @'std_in' == 'CreatePipe'@, then @/mb_stdin_hdl/@ will be @Just /h/@,
       where @/h/@ is the write end of the pipe connected to the child
       process's @stdin@.

     * otherwise, @/mb_stdin_hdl/ == Nothing@

    Similarly for @/mb_stdout_hdl/@ and @/mb_stderr_hdl/@.

    For example, to execute a simple @ls@ command:

    >   r <- createProcess (proc "ls" [])

    To create a pipe from which to read the output of @ls@:

    >   (_, Just hout, _, _) <-
    >       createProcess (proc "ls" []){ std_out = CreatePipe }

    To also set the directory in which to run @ls@:

    >   (_, Just hout, _, _) <-
    >       createProcess (proc "ls" []){ cwd = Just "/home/bob",
    >                                     std_out = CreatePipe }

    Note that @Handle@s provided for @std_in@, @std_out@, or @std_err@ via the
    @UseHandle@ constructor will be closed by calling this function. This is not
    always the desired behavior. In cases where you would like to leave the
    @Handle@ open after spawning the child process, please use 'createProcess_'
    instead. All created @Handle@s are initially in text mode; if you need them
    to be in binary mode then use 'hSetBinaryMode'.

    @/ph/@ contains a handle to the running process.  On Windows
    'use_process_jobs' can be set in CreateProcess in order to create a
    Win32 Job object to monitor a process tree's progress.  If it is set
    then that job is also returned inside @/ph/@.  @/ph/@ can be used to
    kill all running sub-processes.  This feature has been available since
    1.5.0.0.

    -}
    createProcess
      :: CreateProcess
      -> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    createProcess :: CreateProcess
    -> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    createProcess CreateProcess
    cp = do
      (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    r <- String
    -> CreateProcess
    -> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    createProcess_ String
    "createProcess" CreateProcess
    cp
      StdStream -> IO ()
    maybeCloseStd (CreateProcess -> StdStream
    std_in  CreateProcess
    cp)
      StdStream -> IO ()
    maybeCloseStd (CreateProcess -> StdStream
    std_out CreateProcess
    cp)
      StdStream -> IO ()
    maybeCloseStd (CreateProcess -> StdStream
    std_err CreateProcess
    cp)
      (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    -> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    r
     where
      maybeCloseStd :: StdStream -> IO ()
      maybeCloseStd :: StdStream -> IO ()
    maybeCloseStd (UseHandle Handle
    hdl)
        | Handle
    hdl Handle -> Handle -> Bool
    forall a. Eq a => a -> a -> Bool
    /= Handle
    stdin Bool -> Bool -> Bool
    && Handle
    hdl Handle -> Handle -> Bool
    forall a. Eq a => a -> a -> Bool
    /= Handle
    stdout Bool -> Bool -> Bool
    && Handle
    hdl Handle -> Handle -> Bool
    forall a. Eq a => a -> a -> Bool
    /= Handle
    stderr = Handle -> IO ()
    hClose Handle
    hdl
      maybeCloseStd StdStream
    _ = () -> IO ()
    forall (m :: * -> *) a. Monad m => a -> m a
    return ()

    -- | A 'C.bracket'-style resource handler for 'createProcess'.
    --
    -- Does automatic cleanup when the action finishes. If there is an exception
    -- in the body then it ensures that the process gets terminated and any
    -- 'CreatePipe' 'Handle's are closed. In particular this means that if the
    -- Haskell thread is killed (e.g. 'killThread'), that the external process is
    -- also terminated.
    --
    -- e.g.
    --
    -- > withCreateProcess (proc cmd args) { ... }  $ \stdin stdout stderr ph -> do
    -- >   ...
    --
    -- @since 1.4.3.0
    withCreateProcess
      :: CreateProcess
      -> (Maybe Handle -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a)
      -> IO a
    withCreateProcess :: forall a.
    CreateProcess
    -> (Maybe Handle
        -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a)
    -> IO a
    withCreateProcess CreateProcess
    c Maybe Handle
    -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a
    action =
        IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    -> ((Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
        -> IO ())
    -> ((Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
        -> IO a)
    -> IO a
    forall a b c. IO a -> (a -> IO b) -> (a -> IO c) -> IO c
    C.bracket (CreateProcess
    -> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    createProcess CreateProcess
    c) (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle) -> IO ()
    cleanupProcess
                  (\(Maybe Handle
    m_in, Maybe Handle
    m_out, Maybe Handle
    m_err, ProcessHandle
    ph) -> Maybe Handle
    -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a
    action Maybe Handle
    m_in Maybe Handle
    m_out Maybe Handle
    m_err ProcessHandle
    ph)

    -- wrapper so we can get exceptions with the appropriate function name.
    withCreateProcess_
      :: String
      -> CreateProcess
      -> (Maybe Handle -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a)
      -> IO a
    withCreateProcess_ :: forall a.
    String
    -> CreateProcess
    -> (Maybe Handle
        -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a)
    -> IO a
    withCreateProcess_ String
    fun CreateProcess
    c Maybe Handle
    -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a
    action =
        IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    -> ((Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
        -> IO ())
    -> ((Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
        -> IO a)
    -> IO a
    forall a b c. IO a -> (a -> IO b) -> (a -> IO c) -> IO c
    C.bracketOnError (String
    -> CreateProcess
    -> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    createProcess_ String
    fun CreateProcess
    c) (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle) -> IO ()
    cleanupProcess
                         (\(Maybe Handle
    m_in, Maybe Handle
    m_out, Maybe Handle
    m_err, ProcessHandle
    ph) -> Maybe Handle
    -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a
    action Maybe Handle
    m_in Maybe Handle
    m_out Maybe Handle
    m_err ProcessHandle
    ph)

    -- | Cleans up the process.
    --
    -- This function is meant to be invoked from any application level cleanup
    -- handler. It terminates the process, and closes any 'CreatePipe' 'handle's.
    --
    -- @since 1.6.4.0
    cleanupProcess :: (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
                   -> IO ()
    cleanupProcess :: (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle) -> IO ()
    cleanupProcess (Maybe Handle
    mb_stdin, Maybe Handle
    mb_stdout, Maybe Handle
    mb_stderr,
                    ph :: ProcessHandle
    ph@(ProcessHandle MVar ProcessHandle__
    _ Bool
    delegating_ctlc MVar ()
    _)) = do
        ProcessHandle -> IO ()
    terminateProcess ProcessHandle
    ph
        -- Note, it's important that other threads that might be reading/writing
        -- these handles also get killed off, since otherwise they might be holding
        -- the handle lock and prevent us from closing, leading to deadlock.
        IO () -> (Handle -> IO ()) -> Maybe Handle -> IO ()
    forall b a. b -> (a -> b) -> Maybe a -> b
    maybe (() -> IO ()
    forall (m :: * -> *) a. Monad m => a -> m a
    return ()) (IO () -> IO ()
    ignoreSigPipe (IO () -> IO ()) -> (Handle -> IO ()) -> Handle -> IO ()
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Handle -> IO ()
    hClose) Maybe Handle
    mb_stdin
        IO () -> (Handle -> IO ()) -> Maybe Handle -> IO ()
    forall b a. b -> (a -> b) -> Maybe a -> b
    maybe (() -> IO ()
    forall (m :: * -> *) a. Monad m => a -> m a
    return ()) Handle -> IO ()
    hClose Maybe Handle
    mb_stdout
        IO () -> (Handle -> IO ()) -> Maybe Handle -> IO ()
    forall b a. b -> (a -> b) -> Maybe a -> b
    maybe (() -> IO ()
    forall (m :: * -> *) a. Monad m => a -> m a
    return ()) Handle -> IO ()
    hClose Maybe Handle
    mb_stderr
        -- terminateProcess does not guarantee that it terminates the process.
        -- Indeed on Unix it's SIGTERM, which asks nicely but does not guarantee
        -- that it stops. If it doesn't stop, we don't want to hang, so we wait
        -- asynchronously using forkIO.

        -- However we want to end the Ctl-C handling synchronously, so we'll do
        -- that synchronously, and set delegating_ctlc as False for the
        -- waitForProcess (which would otherwise end the Ctl-C delegation itself).
        Bool -> IO () -> IO ()
    forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
    when Bool
    delegating_ctlc
          IO ()
    stopDelegateControlC
        ThreadId
    _ <- IO () -> IO ThreadId
    forkIO (ProcessHandle -> IO ExitCode
    waitForProcess (ProcessHandle -> ProcessHandle
    resetCtlcDelegation ProcessHandle
    ph) IO ExitCode -> IO () -> IO ()
    forall (m :: * -> *) a b. Monad m => m a -> m b -> m b
    >> () -> IO ()
    forall (m :: * -> *) a. Monad m => a -> m a
    return ())
        () -> IO ()
    forall (m :: * -> *) a. Monad m => a -> m a
    return ()
      where
        resetCtlcDelegation :: ProcessHandle -> ProcessHandle
    resetCtlcDelegation (ProcessHandle MVar ProcessHandle__
    m Bool
    _ MVar ()
    l) = MVar ProcessHandle__ -> Bool -> MVar () -> ProcessHandle
    ProcessHandle MVar ProcessHandle__
    m Bool
    False MVar ()
    l

    -- ----------------------------------------------------------------------------
    -- spawnProcess/spawnCommand

    -- | Creates a new process to run the specified raw command with the given
    -- arguments. It does not wait for the program to finish, but returns the
    -- 'ProcessHandle'.
    --
    -- @since 1.2.0.0
    spawnProcess :: FilePath -> [String] -> IO ProcessHandle
    spawnProcess :: String -> [String] -> IO ProcessHandle
    spawnProcess String
    cmd [String]
    args = do
        (Maybe Handle
    _,Maybe Handle
    _,Maybe Handle
    _,ProcessHandle
    p) <- String
    -> CreateProcess
    -> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    createProcess_ String
    "spawnProcess" (String -> [String] -> CreateProcess
    proc String
    cmd [String]
    args)
        ProcessHandle -> IO ProcessHandle
    forall (m :: * -> *) a. Monad m => a -> m a
    return ProcessHandle
    p

    -- | Creates a new process to run the specified shell command.
    -- It does not wait for the program to finish, but returns the 'ProcessHandle'.
    --
    -- @since 1.2.0.0
    spawnCommand :: String -> IO ProcessHandle
    spawnCommand :: String -> IO ProcessHandle
    spawnCommand String
    cmd = do
        (Maybe Handle
    _,Maybe Handle
    _,Maybe Handle
    _,ProcessHandle
    p) <- String
    -> CreateProcess
    -> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    createProcess_ String
    "spawnCommand" (String -> CreateProcess
    shell String
    cmd)
        ProcessHandle -> IO ProcessHandle
    forall (m :: * -> *) a. Monad m => a -> m a
    return ProcessHandle
    p

    -- ----------------------------------------------------------------------------
    -- callProcess/callCommand

    -- | Creates a new process to run the specified command with the given
    -- arguments, and wait for it to finish.  If the command returns a non-zero
    -- exit code, an exception is raised.
    --
    -- If an asynchronous exception is thrown to the thread executing
    -- @callProcess@, the forked process will be terminated and
    -- @callProcess@ will wait (block) until the process has been
    -- terminated.
    --
    -- @since 1.2.0.0
    callProcess :: FilePath -> [String] -> IO ()
    callProcess :: String -> [String] -> IO ()
    callProcess String
    cmd [String]
    args = do
        ExitCode
    exit_code <- String
    -> CreateProcess
    -> (Maybe Handle
        -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO ExitCode)
    -> IO ExitCode
    forall a.
    String
    -> CreateProcess
    -> (Maybe Handle
        -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a)
    -> IO a
    withCreateProcess_ String
    "callProcess"
                       (String -> [String] -> CreateProcess
    proc String
    cmd [String]
    args) { delegate_ctlc :: Bool
    delegate_ctlc = Bool
    True } ((Maybe Handle
      -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO ExitCode)
     -> IO ExitCode)
    -> (Maybe Handle
        -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO ExitCode)
    -> IO ExitCode
    forall a b. (a -> b) -> a -> b
    $ \Maybe Handle
    _ Maybe Handle
    _ Maybe Handle
    _ ProcessHandle
    p ->
                       ProcessHandle -> IO ExitCode
    waitForProcess ProcessHandle
    p
        case ExitCode
    exit_code of
          ExitCode
    ExitSuccess   -> () -> IO ()
    forall (m :: * -> *) a. Monad m => a -> m a
    return ()
          ExitFailure Int
    r -> String -> String -> [String] -> Int -> IO ()
    forall a. String -> String -> [String] -> Int -> IO a
    processFailedException String
    "callProcess" String
    cmd [String]
    args Int
    r

    -- | Creates a new process to run the specified shell command.  If the
    -- command returns a non-zero exit code, an exception is raised.
    --
    -- If an asynchronous exception is thrown to the thread executing
    -- @callCommand@, the forked process will be terminated and
    -- @callCommand@ will wait (block) until the process has been
    -- terminated.
    --
    -- @since 1.2.0.0
    callCommand :: String -> IO ()
    callCommand :: String -> IO ()
    callCommand String
    cmd = do
        ExitCode
    exit_code <- String
    -> CreateProcess
    -> (Maybe Handle
        -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO ExitCode)
    -> IO ExitCode
    forall a.
    String
    -> CreateProcess
    -> (Maybe Handle
        -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a)
    -> IO a
    withCreateProcess_ String
    "callCommand"
                       (String -> CreateProcess
    shell String
    cmd) { delegate_ctlc :: Bool
    delegate_ctlc = Bool
    True } ((Maybe Handle
      -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO ExitCode)
     -> IO ExitCode)
    -> (Maybe Handle
        -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO ExitCode)
    -> IO ExitCode
    forall a b. (a -> b) -> a -> b
    $ \Maybe Handle
    _ Maybe Handle
    _ Maybe Handle
    _ ProcessHandle
    p ->
                       ProcessHandle -> IO ExitCode
    waitForProcess ProcessHandle
    p
        case ExitCode
    exit_code of
          ExitCode
    ExitSuccess   -> () -> IO ()
    forall (m :: * -> *) a. Monad m => a -> m a
    return ()
          ExitFailure Int
    r -> String -> String -> [String] -> Int -> IO ()
    forall a. String -> String -> [String] -> Int -> IO a
    processFailedException String
    "callCommand" String
    cmd [] Int
    r

    processFailedException :: String -> String -> [String] -> Int -> IO a
    processFailedException :: forall a. String -> String -> [String] -> Int -> IO a
    processFailedException String
    fun String
    cmd [String]
    args Int
    exit_code =
          IOException -> IO a
    forall a. IOException -> IO a
    ioError (IOErrorType
    -> String -> Maybe Handle -> Maybe String -> IOException
    mkIOError IOErrorType
    OtherError (String
    fun String -> String -> String
    forall a. [a] -> [a] -> [a]
    ++ String
    ": " String -> String -> String
    forall a. [a] -> [a] -> [a]
    ++ String
    cmd String -> String -> String
    forall a. [a] -> [a] -> [a]
    ++
                                         (String -> String) -> [String] -> String
    forall (t :: * -> *) a b. Foldable t => (a -> [b]) -> t a -> [b]
    concatMap ((Char
    ' 'Char -> String -> String
    forall a. a -> [a] -> [a]
    :) (String -> String) -> (String -> String) -> String -> String
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . String -> String
    forall a. Show a => a -> String
    show) [String]
    args String -> String -> String
    forall a. [a] -> [a] -> [a]
    ++
                                         String
    " (exit " String -> String -> String
    forall a. [a] -> [a] -> [a]
    ++ Int -> String
    forall a. Show a => a -> String
    show Int
    exit_code String -> String -> String
    forall a. [a] -> [a] -> [a]
    ++ String
    ")")
                                     Maybe Handle
    forall a. Maybe a
    Nothing Maybe String
    forall a. Maybe a
    Nothing)

    -- ----------------------------------------------------------------------------
    -- Control-C handling on Unix

    -- $ctlc-handling
    --
    -- When running an interactive console process (such as a shell, console-based
    -- text editor or ghci), we typically want that process to be allowed to handle
    -- Ctl-C keyboard interrupts how it sees fit. For example, while most programs
    -- simply quit on a Ctl-C, some handle it specially. To allow this to happen,
    -- use the @'delegate_ctlc' = True@ option in the 'CreateProcess' options.
    --
    -- The gory details:
    --
    -- By default Ctl-C will generate a @SIGINT@ signal, causing a 'UserInterrupt'
    -- exception to be sent to the main Haskell thread of your program, which if
    -- not specially handled will terminate the program. Normally, this is exactly
    -- what is wanted: an orderly shutdown of the program in response to Ctl-C.
    --
    -- Of course when running another interactive program in the console then we
    -- want to let that program handle Ctl-C. Under Unix however, Ctl-C sends
    -- @SIGINT@ to every process using the console. The standard solution is that
    -- while running an interactive program, ignore @SIGINT@ in the parent, and let
    -- it be handled in the child process. If that process then terminates due to
    -- the @SIGINT@ signal, then at that point treat it as if we had recieved the
    -- @SIGINT@ ourselves and begin an orderly shutdown.
    --
    -- This behaviour is implemented by 'createProcess' (and
    -- 'waitForProcess' \/ 'getProcessExitCode') when the @'delegate_ctlc' = True@
    -- option is set. In particular, the @SIGINT@ signal will be ignored until
    -- 'waitForProcess' returns (or 'getProcessExitCode' returns a non-Nothing
    -- result), so it becomes especially important to use 'waitForProcess' for every
    -- processes created.
    --
    -- In addition, in 'delegate_ctlc' mode, 'waitForProcess' and
    -- 'getProcessExitCode' will throw a 'UserInterrupt' exception if the process
    -- terminated with @'ExitFailure' (-SIGINT)@. Typically you will not want to
    -- catch this exception, but let it propagate, giving a normal orderly shutdown.
    -- One detail to be aware of is that the 'UserInterrupt' exception is thrown
    -- /synchronously/ in the thread that calls 'waitForProcess', whereas normally
    -- @SIGINT@ causes the exception to be thrown /asynchronously/ to the main
    -- thread.
    --
    -- For even more detail on this topic, see
    -- <http://www.cons.org/cracauer/sigint.html "Proper handling of SIGINT/SIGQUIT">.

    -- $exec-on-windows
    --
    -- Note that processes which use the POSIX @exec@ system call (e.g. @gcc@)
    -- require special care on Windows. Specifically, the @msvcrt@ C runtime used
    -- frequently on Windows emulates @exec@ in a non-POSIX compliant manner, where
    -- the caller will be terminated (with exit code 0) and execution will continue
    -- in a new process. As a result, on Windows it will appear as though a child
    -- process which has called @exec@ has terminated despite the fact that the
    -- process would still be running on a POSIX-compliant platform.
    --
    -- Since many programs do use @exec@, the @process@ library exposes the
    -- 'use_process_jobs' flag to make it possible to reliably detect when such a
    -- process completes. When this flag is set a 'ProcessHandle' will not be
    -- deemed to be \"finished\" until all processes spawned by it have
    -- terminated (except those spawned by the child with the
    -- @CREATE_BREAKAWAY_FROM_JOB@ @CreateProcess@ flag).
    --
    -- Note, however, that, because of platform limitations, the exit code returned
    -- by @waitForProcess@ and @getProcessExitCode@ cannot not be relied upon when
    -- the child uses @exec@, even when 'use_process_jobs' is used. Specifically,
    -- these functions will return the exit code of the *original child* (which
    -- always exits with code 0, since it called @exec@), not the exit code of the
    -- process which carried on with execution after @exec@. This is different from
    -- the behavior prescribed by POSIX but is the best approximation that can be
    -- realised under the restrictions of the Windows process model.

    -- -----------------------------------------------------------------------------

    -- | @readProcess@ forks an external process, reads its standard output
    -- strictly, blocking until the process terminates, and returns the output
    -- string. The external process inherits the standard error.
    --
    -- If an asynchronous exception is thrown to the thread executing
    -- @readProcess@, the forked process will be terminated and @readProcess@ will
    -- wait (block) until the process has been terminated.
    --
    -- Output is returned strictly, so this is not suitable for launching processes
    -- that require interaction over the standard file streams.
    --
    -- This function throws an 'IOError' if the process 'ExitCode' is
    -- anything other than 'ExitSuccess'. If instead you want to get the
    -- 'ExitCode' then use 'readProcessWithExitCode'.
    --
    -- Users of this function should compile with @-threaded@ if they
    -- want other Haskell threads to keep running while waiting on
    -- the result of readProcess.
    --
    -- >  > readProcess "date" [] []
    -- >  "Thu Feb  7 10:03:39 PST 2008\n"
    --
    -- The arguments are:
    --
    -- * The command to run, which must be in the $PATH, or an absolute or relative path
    --
    -- * A list of separate command line arguments to the program
    --
    -- * A string to pass on standard input to the forked process.
    --
    readProcess
        :: FilePath                 -- ^ Filename of the executable (see 'RawCommand' for details)
        -> [String]                 -- ^ any arguments
        -> String                   -- ^ standard input
        -> IO String                -- ^ stdout
    readProcess :: String -> [String] -> String -> IO String
    readProcess String
    cmd [String]
    args = CreateProcess -> String -> IO String
    readCreateProcess (CreateProcess -> String -> IO String)
    -> CreateProcess -> String -> IO String
    forall a b. (a -> b) -> a -> b
    $ String -> [String] -> CreateProcess
    proc String
    cmd [String]
    args

    -- | @readCreateProcess@ works exactly like 'readProcess' except that it
    -- lets you pass 'CreateProcess' giving better flexibility.
    --
    -- >  > readCreateProcess ((shell "pwd") { cwd = Just "/etc/" }) ""
    -- >  "/etc\n"
    --
    -- Note that @Handle@s provided for @std_in@ or @std_out@ via the CreateProcess
    -- record will be ignored.
    --
    -- @since 1.2.3.0

    readCreateProcess
        :: CreateProcess
        -> String                   -- ^ standard input
        -> IO String                -- ^ stdout
    readCreateProcess :: CreateProcess -> String -> IO String
    readCreateProcess CreateProcess
    cp String
    input = do
        let cp_opts :: CreateProcess
    cp_opts = CreateProcess
    cp {
                        std_in :: StdStream
    std_in  = StdStream
    CreatePipe,
                        std_out :: StdStream
    std_out = StdStream
    CreatePipe
                      }
        (ExitCode
    ex, String
    output) <- String
    -> CreateProcess
    -> (Maybe Handle
        -> Maybe Handle
        -> Maybe Handle
        -> ProcessHandle
        -> IO (ExitCode, String))
    -> IO (ExitCode, String)
    forall a.
    String
    -> CreateProcess
    -> (Maybe Handle
        -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a)
    -> IO a
    withCreateProcess_ String
    "readCreateProcess" CreateProcess
    cp_opts ((Maybe Handle
      -> Maybe Handle
      -> Maybe Handle
      -> ProcessHandle
      -> IO (ExitCode, String))
     -> IO (ExitCode, String))
    -> (Maybe Handle
        -> Maybe Handle
        -> Maybe Handle
        -> ProcessHandle
        -> IO (ExitCode, String))
    -> IO (ExitCode, String)
    forall a b. (a -> b) -> a -> b
    $
          \Maybe Handle
    mb_inh Maybe Handle
    mb_outh Maybe Handle
    _ ProcessHandle
    ph ->
            case (Maybe Handle
    mb_inh, Maybe Handle
    mb_outh) of
              (Just Handle
    inh, Just Handle
    outh) -> do

                -- fork off a thread to start consuming the output
                String
    output  <- Handle -> IO String
    hGetContents Handle
    outh
                IO () -> (IO () -> IO ()) -> IO ()
    forall a. IO () -> (IO () -> IO a) -> IO a
    withForkWait (() -> IO ()
    forall a. a -> IO a
    C.evaluate (() -> IO ()) -> () -> IO ()
    forall a b. (a -> b) -> a -> b
    $ String -> ()
    forall a. NFData a => a -> ()
    rnf String
    output) ((IO () -> IO ()) -> IO ()) -> (IO () -> IO ()) -> IO ()
    forall a b. (a -> b) -> a -> b
    $ \IO ()
    waitOut -> do

                  -- now write any input
                  Bool -> IO () -> IO ()
    forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
    unless (String -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null String
    input) (IO () -> IO ()) -> IO () -> IO ()
    forall a b. (a -> b) -> a -> b
    $
                    IO () -> IO ()
    ignoreSigPipe (IO () -> IO ()) -> IO () -> IO ()
    forall a b. (a -> b) -> a -> b
    $ Handle -> String -> IO ()
    hPutStr Handle
    inh String
    input
                  -- hClose performs implicit hFlush, and thus may trigger a SIGPIPE
                  IO () -> IO ()
    ignoreSigPipe (IO () -> IO ()) -> IO () -> IO ()
    forall a b. (a -> b) -> a -> b
    $ Handle -> IO ()
    hClose Handle
    inh

                  -- wait on the output
                  IO ()
    waitOut
                  Handle -> IO ()
    hClose Handle
    outh

                -- wait on the process
                ExitCode
    ex <- ProcessHandle -> IO ExitCode
    waitForProcess ProcessHandle
    ph
                (ExitCode, String) -> IO (ExitCode, String)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (ExitCode
    ex, String
    output)

              (Maybe Handle
    Nothing,Maybe Handle
    _) -> String -> IO (ExitCode, String)
    forall a. HasCallStack => String -> a
    error String
    "readCreateProcess: Failed to get a stdin handle."
              (Maybe Handle
    _,Maybe Handle
    Nothing) -> String -> IO (ExitCode, String)
    forall a. HasCallStack => String -> a
    error String
    "readCreateProcess: Failed to get a stdout handle."

        case ExitCode
    ex of
         ExitCode
    ExitSuccess   -> String -> IO String
    forall (m :: * -> *) a. Monad m => a -> m a
    return String
    output
         ExitFailure Int
    r -> String -> String -> [String] -> Int -> IO String
    forall a. String -> String -> [String] -> Int -> IO a
    processFailedException String
    "readCreateProcess" String
    cmd [String]
    args Int
    r
      where
        cmd :: String
    cmd = case CreateProcess
    cp of
                CreateProcess { cmdspec :: CreateProcess -> CmdSpec
    cmdspec = ShellCommand String
    sc } -> String
    sc
                CreateProcess { cmdspec :: CreateProcess -> CmdSpec
    cmdspec = RawCommand String
    fp [String]
    _ } -> String
    fp
        args :: [String]
    args = case CreateProcess
    cp of
                 CreateProcess { cmdspec :: CreateProcess -> CmdSpec
    cmdspec = ShellCommand String
    _ } -> []
                 CreateProcess { cmdspec :: CreateProcess -> CmdSpec
    cmdspec = RawCommand String
    _ [String]
    args' } -> [String]
    args'

    -- | @readProcessWithExitCode@ is like 'readProcess' but with two differences:
    --
    --  * it returns the 'ExitCode' of the process, and does not throw any
    --    exception if the code is not 'ExitSuccess'.
    --
    --  * it reads and returns the output from process' standard error handle,
    --    rather than the process inheriting the standard error handle.
    --
    -- On Unix systems, see 'waitForProcess' for the meaning of exit codes
    -- when the process died as the result of a signal.
    --
    readProcessWithExitCode
        :: FilePath                 -- ^ Filename of the executable (see 'RawCommand' for details)
        -> [String]                 -- ^ any arguments
        -> String                   -- ^ standard input
        -> IO (ExitCode,String,String) -- ^ exitcode, stdout, stderr
    readProcessWithExitCode :: String -> [String] -> String -> IO (ExitCode, String, String)
    readProcessWithExitCode String
    cmd [String]
    args =
        CreateProcess -> String -> IO (ExitCode, String, String)
    readCreateProcessWithExitCode (CreateProcess -> String -> IO (ExitCode, String, String))
    -> CreateProcess -> String -> IO (ExitCode, String, String)
    forall a b. (a -> b) -> a -> b
    $ String -> [String] -> CreateProcess
    proc String
    cmd [String]
    args

    -- | @readCreateProcessWithExitCode@ works exactly like 'readProcessWithExitCode' except that it
    -- lets you pass 'CreateProcess' giving better flexibility.
    --
    -- Note that @Handle@s provided for @std_in@, @std_out@, or @std_err@ via the CreateProcess
    -- record will be ignored.
    --
    -- @since 1.2.3.0
    readCreateProcessWithExitCode
        :: CreateProcess
        -> String                      -- ^ standard input
        -> IO (ExitCode,String,String) -- ^ exitcode, stdout, stderr
    readCreateProcessWithExitCode :: CreateProcess -> String -> IO (ExitCode, String, String)
    readCreateProcessWithExitCode CreateProcess
    cp String
    input = do
        let cp_opts :: CreateProcess
    cp_opts = CreateProcess
    cp {
                        std_in :: StdStream
    std_in  = StdStream
    CreatePipe,
                        std_out :: StdStream
    std_out = StdStream
    CreatePipe,
                        std_err :: StdStream
    std_err = StdStream
    CreatePipe
                      }
        String
    -> CreateProcess
    -> (Maybe Handle
        -> Maybe Handle
        -> Maybe Handle
        -> ProcessHandle
        -> IO (ExitCode, String, String))
    -> IO (ExitCode, String, String)
    forall a.
    String
    -> CreateProcess
    -> (Maybe Handle
        -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a)
    -> IO a
    withCreateProcess_ String
    "readCreateProcessWithExitCode" CreateProcess
    cp_opts ((Maybe Handle
      -> Maybe Handle
      -> Maybe Handle
      -> ProcessHandle
      -> IO (ExitCode, String, String))
     -> IO (ExitCode, String, String))
    -> (Maybe Handle
        -> Maybe Handle
        -> Maybe Handle
        -> ProcessHandle
        -> IO (ExitCode, String, String))
    -> IO (ExitCode, String, String)
    forall a b. (a -> b) -> a -> b
    $
          \Maybe Handle
    mb_inh Maybe Handle
    mb_outh Maybe Handle
    mb_errh ProcessHandle
    ph ->
            case (Maybe Handle
    mb_inh, Maybe Handle
    mb_outh, Maybe Handle
    mb_errh) of
              (Just Handle
    inh, Just Handle
    outh, Just Handle
    errh) -> do

                String
    out <- Handle -> IO String
    hGetContents Handle
    outh
                String
    err <- Handle -> IO String
    hGetContents Handle
    errh

                -- fork off threads to start consuming stdout & stderr
                IO () -> (IO () -> IO ()) -> IO ()
    forall a. IO () -> (IO () -> IO a) -> IO a
    withForkWait  (() -> IO ()
    forall a. a -> IO a
    C.evaluate (() -> IO ()) -> () -> IO ()
    forall a b. (a -> b) -> a -> b
    $ String -> ()
    forall a. NFData a => a -> ()
    rnf String
    out) ((IO () -> IO ()) -> IO ()) -> (IO () -> IO ()) -> IO ()
    forall a b. (a -> b) -> a -> b
    $ \IO ()
    waitOut ->
                 IO () -> (IO () -> IO ()) -> IO ()
    forall a. IO () -> (IO () -> IO a) -> IO a
    withForkWait (() -> IO ()
    forall a. a -> IO a
    C.evaluate (() -> IO ()) -> () -> IO ()
    forall a b. (a -> b) -> a -> b
    $ String -> ()
    forall a. NFData a => a -> ()
    rnf String
    err) ((IO () -> IO ()) -> IO ()) -> (IO () -> IO ()) -> IO ()
    forall a b. (a -> b) -> a -> b
    $ \IO ()
    waitErr -> do

                  -- now write any input
                  Bool -> IO () -> IO ()
    forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
    unless (String -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null String
    input) (IO () -> IO ()) -> IO () -> IO ()
    forall a b. (a -> b) -> a -> b
    $
                    IO () -> IO ()
    ignoreSigPipe (IO () -> IO ()) -> IO () -> IO ()
    forall a b. (a -> b) -> a -> b
    $ Handle -> String -> IO ()
    hPutStr Handle
    inh String
    input
                  -- hClose performs implicit hFlush, and thus may trigger a SIGPIPE
                  IO () -> IO ()
    ignoreSigPipe (IO () -> IO ()) -> IO () -> IO ()
    forall a b. (a -> b) -> a -> b
    $ Handle -> IO ()
    hClose Handle
    inh

                  -- wait on the output
                  IO ()
    waitOut
                  IO ()
    waitErr

                  Handle -> IO ()
    hClose Handle
    outh
                  Handle -> IO ()
    hClose Handle
    errh

                -- wait on the process
                ExitCode
    ex <- ProcessHandle -> IO ExitCode
    waitForProcess ProcessHandle
    ph
                (ExitCode, String, String) -> IO (ExitCode, String, String)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (ExitCode
    ex, String
    out, String
    err)

              (Maybe Handle
    Nothing,Maybe Handle
    _,Maybe Handle
    _) -> String -> IO (ExitCode, String, String)
    forall a. HasCallStack => String -> a
    error String
    "readCreateProcessWithExitCode: Failed to get a stdin handle."
              (Maybe Handle
    _,Maybe Handle
    Nothing,Maybe Handle
    _) -> String -> IO (ExitCode, String, String)
    forall a. HasCallStack => String -> a
    error String
    "readCreateProcessWithExitCode: Failed to get a stdout handle."
              (Maybe Handle
    _,Maybe Handle
    _,Maybe Handle
    Nothing) -> String -> IO (ExitCode, String, String)
    forall a. HasCallStack => String -> a
    error String
    "readCreateProcessWithExitCode: Failed to get a stderr handle."

    -- | Fork a thread while doing something else, but kill it if there's an
    -- exception.
    --
    -- This is important in the cases above because we want to kill the thread
    -- that is holding the Handle lock, because when we clean up the process we
    -- try to close that handle, which could otherwise deadlock.
    --
    withForkWait :: IO () -> (IO () ->  IO a) -> IO a
    withForkWait :: forall a. IO () -> (IO () -> IO a) -> IO a
    withForkWait IO ()
    async IO () -> IO a
    body = do
      MVar (Either SomeException ())
    waitVar <- IO (MVar (Either SomeException ()))
    forall a. IO (MVar a)
    newEmptyMVar :: IO (MVar (Either SomeException ()))
      ((forall a. IO a -> IO a) -> IO a) -> IO a
    forall b. ((forall a. IO a -> IO a) -> IO b) -> IO b
    mask (((forall a. IO a -> IO a) -> IO a) -> IO a)
    -> ((forall a. IO a -> IO a) -> IO a) -> IO a
    forall a b. (a -> b) -> a -> b
    $ \forall a. IO a -> IO a
    restore -> do
        ThreadId
    tid <- IO () -> IO ThreadId
    forkIO (IO () -> IO ThreadId) -> IO () -> IO ThreadId
    forall a b. (a -> b) -> a -> b
    $ IO () -> IO (Either SomeException ())
    forall e a. Exception e => IO a -> IO (Either e a)
    try (IO () -> IO ()
    forall a. IO a -> IO a
    restore IO ()
    async) IO (Either SomeException ())
    -> (Either SomeException () -> IO ()) -> IO ()
    forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
    >>= MVar (Either SomeException ()) -> Either SomeException () -> IO ()
    forall a. MVar a -> a -> IO ()
    putMVar MVar (Either SomeException ())
    waitVar
        let wait :: IO ()
    wait = MVar (Either SomeException ()) -> IO (Either SomeException ())
    forall a. MVar a -> IO a
    takeMVar MVar (Either SomeException ())
    waitVar IO (Either SomeException ())
    -> (Either SomeException () -> IO ()) -> IO ()
    forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
    >>= (SomeException -> IO ())
    -> (() -> IO ()) -> Either SomeException () -> IO ()
    forall a c b. (a -> c) -> (b -> c) -> Either a b -> c
    either SomeException -> IO ()
    forall e a. Exception e => e -> IO a
    throwIO () -> IO ()
    forall (m :: * -> *) a. Monad m => a -> m a
    return
        IO a -> IO a
    forall a. IO a -> IO a
    restore (IO () -> IO a
    body IO ()
    wait) IO a -> IO () -> IO a
    forall a b. IO a -> IO b -> IO a
    `C.onException` ThreadId -> IO ()
    killThread ThreadId
    tid

    ignoreSigPipe :: IO () -> IO ()
    ignoreSigPipe :: IO () -> IO ()
    ignoreSigPipe = (IOException -> IO ()) -> IO () -> IO ()
    forall e a. Exception e => (e -> IO a) -> IO a -> IO a
    C.handle ((IOException -> IO ()) -> IO () -> IO ())
    -> (IOException -> IO ()) -> IO () -> IO ()
    forall a b. (a -> b) -> a -> b
    $ \IOException
    e -> case IOException
    e of
                                       IOError { ioe_type :: IOException -> IOErrorType
    ioe_type  = IOErrorType
    ResourceVanished
                                               , ioe_errno :: IOException -> Maybe CInt
    ioe_errno = Just CInt
    ioe }
                                         | CInt -> Errno
    Errno CInt
    ioe Errno -> Errno -> Bool
    forall a. Eq a => a -> a -> Bool
    == Errno
    ePIPE -> () -> IO ()
    forall (m :: * -> *) a. Monad m => a -> m a
    return ()
                                       IOException
    _ -> IOException -> IO ()
    forall e a. Exception e => e -> IO a
    throwIO IOException
    e

    -- ----------------------------------------------------------------------------
    -- showCommandForUser

    -- | Given a program @/p/@ and arguments @/args/@,
    --   @showCommandForUser /p/ /args/@ returns a string suitable for pasting
    --   into @\/bin\/sh@ (on Unix systems) or @CMD.EXE@ (on Windows).
    showCommandForUser :: FilePath -> [String] -> String
    showCommandForUser :: String -> [String] -> String
    showCommandForUser String
    cmd [String]
    args = [String] -> String
    unwords ((String -> String) -> [String] -> [String]
    forall a b. (a -> b) -> [a] -> [b]
    map String -> String
    translate (String
    cmd String -> [String] -> [String]
    forall a. a -> [a] -> [a]
    : [String]
    args))

    -- ----------------------------------------------------------------------------
    -- getPid

    -- | Returns the PID (process ID) of a subprocess.
    --
    -- 'Nothing' is returned if the handle was already closed. Otherwise a
    -- PID is returned that remains valid as long as the handle is open.
    -- The operating system may reuse the PID as soon as the last handle to
    -- the process is closed.
    --
    -- @since 1.6.3.0
    getPid :: ProcessHandle -> IO (Maybe Pid)
    getPid :: ProcessHandle -> IO (Maybe Pid)
    getPid (ProcessHandle MVar ProcessHandle__
    mh Bool
    _ MVar ()
    _) = do
      ProcessHandle__
    p_ <- MVar ProcessHandle__ -> IO ProcessHandle__
    forall a. MVar a -> IO a
    readMVar MVar ProcessHandle__
    mh
      case ProcessHandle__
    p_ of
    #ifdef WINDOWS
        OpenHandle h -> do
          pid <- getProcessId h
          return $ Just pid
    #else
        OpenHandle Pid
    pid -> Maybe Pid -> IO (Maybe Pid)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (Maybe Pid -> IO (Maybe Pid)) -> Maybe Pid -> IO (Maybe Pid)
    forall a b. (a -> b) -> a -> b
    $ Pid -> Maybe Pid
    forall a. a -> Maybe a
    Just Pid
    pid
    #endif
        ProcessHandle__
    _ -> Maybe Pid -> IO (Maybe Pid)
    forall (m :: * -> *) a. Monad m => a -> m a
    return Maybe Pid
    forall a. Maybe a
    Nothing

    -- ----------------------------------------------------------------------------
    -- getCurrentPid

    -- | Returns the PID (process ID) of the current process. On POSIX systems,
    -- this calls 'getProcessID' from "System.Posix.Process" in the @unix@ package.
    -- On Windows, this calls 'getCurrentProcessId' from "System.Win32.Process" in
    -- the @Win32@ package.
    --
    -- @since 1.6.12.0
    getCurrentPid :: IO Pid
    getCurrentPid :: IO Pid
    getCurrentPid =
    #ifdef WINDOWS
        getCurrentProcessId
    #else
        IO Pid
    getProcessID
    #endif

    -- ----------------------------------------------------------------------------
    -- waitForProcess

    {- | Waits for the specified process to terminate, and returns its exit code.

    GHC Note: in order to call @waitForProcess@ without blocking all the
    other threads in the system, you must compile the program with
    @-threaded@.

    Note that it is safe to call @waitForProcess@ for the same process in multiple
    threads. When the process ends, threads blocking on this call will wake in
    FIFO order.

    (/Since: 1.2.0.0/) On Unix systems, a negative value @'ExitFailure' -/signum/@
    indicates that the child was terminated by signal @/signum/@.
    The signal numbers are platform-specific, so to test for a specific signal use
    the constants provided by "System.Posix.Signals" in the @unix@ package.
    Note: core dumps are not reported, use "System.Posix.Process" if you need this
    detail.

    -}
    waitForProcess
      :: ProcessHandle
      -> IO ExitCode
    waitForProcess :: ProcessHandle -> IO ExitCode
    waitForProcess ph :: ProcessHandle
    ph@(ProcessHandle MVar ProcessHandle__
    _ Bool
    delegating_ctlc MVar ()
    _) = IO ExitCode -> IO ExitCode
    forall a. IO a -> IO a
    lockWaitpid (IO ExitCode -> IO ExitCode) -> IO ExitCode -> IO ExitCode
    forall a b. (a -> b) -> a -> b
    $ do
      ProcessHandle__
    p_ <- ProcessHandle
    -> (ProcessHandle__ -> IO (ProcessHandle__, ProcessHandle__))
    -> IO ProcessHandle__
    forall a.
    ProcessHandle
    -> (ProcessHandle__ -> IO (ProcessHandle__, a)) -> IO a
    modifyProcessHandle ProcessHandle
    ph ((ProcessHandle__ -> IO (ProcessHandle__, ProcessHandle__))
     -> IO ProcessHandle__)
    -> (ProcessHandle__ -> IO (ProcessHandle__, ProcessHandle__))
    -> IO ProcessHandle__
    forall a b. (a -> b) -> a -> b
    $ \ProcessHandle__
    p_ -> (ProcessHandle__, ProcessHandle__)
    -> IO (ProcessHandle__, ProcessHandle__)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (ProcessHandle__
    p_,ProcessHandle__
    p_)
      case ProcessHandle__
    p_ of
        ClosedHandle ExitCode
    e -> ExitCode -> IO ExitCode
    forall (m :: * -> *) a. Monad m => a -> m a
    return ExitCode
    e
        OpenHandle Pid
    h  -> do
            -- don't hold the MVar while we call c_waitForProcess...
            ExitCode
    e <- Pid -> IO ExitCode
    waitForProcess' Pid
    h
            ExitCode
    e' <- ProcessHandle
    -> (ProcessHandle__ -> IO (ProcessHandle__, ExitCode))
    -> IO ExitCode
    forall a.
    ProcessHandle
    -> (ProcessHandle__ -> IO (ProcessHandle__, a)) -> IO a
    modifyProcessHandle ProcessHandle
    ph ((ProcessHandle__ -> IO (ProcessHandle__, ExitCode))
     -> IO ExitCode)
    -> (ProcessHandle__ -> IO (ProcessHandle__, ExitCode))
    -> IO ExitCode
    forall a b. (a -> b) -> a -> b
    $ \ProcessHandle__
    p_' ->
              case ProcessHandle__
    p_' of
                ClosedHandle ExitCode
    e' -> (ProcessHandle__, ExitCode) -> IO (ProcessHandle__, ExitCode)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (ProcessHandle__
    p_', ExitCode
    e')
                OpenExtHandle{} -> String -> IO (ProcessHandle__, ExitCode)
    forall (m :: * -> *) a. MonadFail m => String -> m a
    fail String
    "waitForProcess(OpenExtHandle): this cannot happen"
                OpenHandle Pid
    ph'  -> do
                  Pid -> IO ()
    closePHANDLE Pid
    ph'
                  Bool -> IO () -> IO ()
    forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
    when Bool
    delegating_ctlc (IO () -> IO ()) -> IO () -> IO ()
    forall a b. (a -> b) -> a -> b
    $
                    ExitCode -> IO ()
    endDelegateControlC ExitCode
    e
                  (ProcessHandle__, ExitCode) -> IO (ProcessHandle__, ExitCode)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (ExitCode -> ProcessHandle__
    ClosedHandle ExitCode
    e, ExitCode
    e)
            ExitCode -> IO ExitCode
    forall (m :: * -> *) a. Monad m => a -> m a
    return ExitCode
    e'
    #if defined(WINDOWS)
        OpenExtHandle h job -> do
            -- First wait for completion of the job...
            waitForJobCompletion job
            e <- waitForProcess' h
            e' <- modifyProcessHandle ph $ \p_' ->
              case p_' of
                ClosedHandle e' -> return (p_', e')
                OpenHandle{}    -> fail "waitForProcess(OpenHandle): this cannot happen"
                OpenExtHandle ph' job' -> do
                  closePHANDLE ph'
                  closePHANDLE job'
                  when delegating_ctlc $
                    endDelegateControlC e
                  return (ClosedHandle e, e)
            return e'
    #else
        OpenExtHandle Pid
    _ Pid
    _job ->
            ExitCode -> IO ExitCode
    forall (m :: * -> *) a. Monad m => a -> m a
    return (ExitCode -> IO ExitCode) -> ExitCode -> IO ExitCode
    forall a b. (a -> b) -> a -> b
    $ Int -> ExitCode
    ExitFailure (-Int
    1)
    #endif
      where
        -- If more than one thread calls `waitpid` at a time, `waitpid` will
        -- return the exit code to one of them and (-1) to the rest of them,
        -- causing an exception to be thrown.
        -- Cf. https://github.com/haskell/process/issues/46, and
        -- https://github.com/haskell/process/pull/58 for further discussion
        lockWaitpid :: IO b -> IO b
    lockWaitpid IO b
    m = MVar () -> (() -> IO b) -> IO b
    forall a b. MVar a -> (a -> IO b) -> IO b
    withMVar (ProcessHandle -> MVar ()
    waitpidLock ProcessHandle
    ph) ((() -> IO b) -> IO b) -> (() -> IO b) -> IO b
    forall a b. (a -> b) -> a -> b
    $ \() -> IO b
    m

        waitForProcess' :: PHANDLE -> IO ExitCode
        waitForProcess' :: Pid -> IO ExitCode
    waitForProcess' Pid
    h = (Ptr CInt -> IO ExitCode) -> IO ExitCode
    forall a b. Storable a => (Ptr a -> IO b) -> IO b
    alloca ((Ptr CInt -> IO ExitCode) -> IO ExitCode)
    -> (Ptr CInt -> IO ExitCode) -> IO ExitCode
    forall a b. (a -> b) -> a -> b
    $ \Ptr CInt
    pret -> do
          String -> IO CInt -> IO ()
    forall a. (Eq a, Num a) => String -> IO a -> IO ()
    throwErrnoIfMinus1Retry_ String
    "waitForProcess" (IO ()
    allowInterrupt IO () -> IO CInt -> IO CInt
    forall (m :: * -> *) a b. Monad m => m a -> m b -> m b
    >> Pid -> Ptr CInt -> IO CInt
    c_waitForProcess Pid
    h Ptr CInt
    pret)
          CInt -> ExitCode
    mkExitCode (CInt -> ExitCode) -> IO CInt -> IO ExitCode
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    <$> Ptr CInt -> IO CInt
    forall a. Storable a => Ptr a -> IO a
    peek Ptr CInt
    pret

        mkExitCode :: CInt -> ExitCode
        mkExitCode :: CInt -> ExitCode
    mkExitCode CInt
    code
          | CInt
    code CInt -> CInt -> Bool
    forall a. Eq a => a -> a -> Bool
    == CInt
    0 = ExitCode
    ExitSuccess
          | Bool
    otherwise = Int -> ExitCode
    ExitFailure (CInt -> Int
    forall a b. (Integral a, Num b) => a -> b
    fromIntegral CInt
    code)

    -- ----------------------------------------------------------------------------
    -- getProcessExitCode

    {- |
    This is a non-blocking version of 'waitForProcess'.  If the process is
    still running, 'Nothing' is returned.  If the process has exited, then
    @'Just' e@ is returned where @e@ is the exit code of the process.

    On Unix systems, see 'waitForProcess' for the meaning of exit codes
    when the process died as the result of a signal.
    -}

    getProcessExitCode :: ProcessHandle -> IO (Maybe ExitCode)
    getProcessExitCode :: ProcessHandle -> IO (Maybe ExitCode)
    getProcessExitCode ph :: ProcessHandle
    ph@(ProcessHandle MVar ProcessHandle__
    _ Bool
    delegating_ctlc MVar ()
    _) = IO (Maybe ExitCode) -> IO (Maybe ExitCode)
    tryLockWaitpid (IO (Maybe ExitCode) -> IO (Maybe ExitCode))
    -> IO (Maybe ExitCode) -> IO (Maybe ExitCode)
    forall a b. (a -> b) -> a -> b
    $ do
      (Maybe ExitCode
    m_e, Bool
    was_open) <- ProcessHandle
    -> (ProcessHandle__
        -> IO (ProcessHandle__, (Maybe ExitCode, Bool)))
    -> IO (Maybe ExitCode, Bool)
    forall a.
    ProcessHandle
    -> (ProcessHandle__ -> IO (ProcessHandle__, a)) -> IO a
    modifyProcessHandle ProcessHandle
    ph ((ProcessHandle__ -> IO (ProcessHandle__, (Maybe ExitCode, Bool)))
     -> IO (Maybe ExitCode, Bool))
    -> (ProcessHandle__
        -> IO (ProcessHandle__, (Maybe ExitCode, Bool)))
    -> IO (Maybe ExitCode, Bool)
    forall a b. (a -> b) -> a -> b
    $ \ProcessHandle__
    p_ ->
        case ProcessHandle__
    p_ of
          ClosedHandle ExitCode
    e -> (ProcessHandle__, (Maybe ExitCode, Bool))
    -> IO (ProcessHandle__, (Maybe ExitCode, Bool))
    forall (m :: * -> *) a. Monad m => a -> m a
    return (ProcessHandle__
    p_, (ExitCode -> Maybe ExitCode
    forall a. a -> Maybe a
    Just ExitCode
    e, Bool
    False))
          ProcessHandle__
    open -> do
            (Ptr CInt -> IO (ProcessHandle__, (Maybe ExitCode, Bool)))
    -> IO (ProcessHandle__, (Maybe ExitCode, Bool))
    forall a b. Storable a => (Ptr a -> IO b) -> IO b
    alloca ((Ptr CInt -> IO (ProcessHandle__, (Maybe ExitCode, Bool)))
     -> IO (ProcessHandle__, (Maybe ExitCode, Bool)))
    -> (Ptr CInt -> IO (ProcessHandle__, (Maybe ExitCode, Bool)))
    -> IO (ProcessHandle__, (Maybe ExitCode, Bool))
    forall a b. (a -> b) -> a -> b
    $ \Ptr CInt
    pExitCode -> do
              case ProcessHandle__ -> Maybe Pid
    getHandle ProcessHandle__
    open of
                Maybe Pid
    Nothing -> (ProcessHandle__, (Maybe ExitCode, Bool))
    -> IO (ProcessHandle__, (Maybe ExitCode, Bool))
    forall (m :: * -> *) a. Monad m => a -> m a
    return (ProcessHandle__
    p_, (Maybe ExitCode
    forall a. Maybe a
    Nothing, Bool
    False))
                Just Pid
    h  -> do
                    CInt
    res <- String -> IO CInt -> IO CInt
    forall a. (Eq a, Num a) => String -> IO a -> IO a
    throwErrnoIfMinus1Retry String
    "getProcessExitCode" (IO CInt -> IO CInt) -> IO CInt -> IO CInt
    forall a b. (a -> b) -> a -> b
    $
                                            Pid -> Ptr CInt -> IO CInt
    c_getProcessExitCode Pid
    h Ptr CInt
    pExitCode
                    CInt
    code <- Ptr CInt -> IO CInt
    forall a. Storable a => Ptr a -> IO a
    peek Ptr CInt
    pExitCode
                    if CInt
    res CInt -> CInt -> Bool
    forall a. Eq a => a -> a -> Bool
    == CInt
    0
                       then (ProcessHandle__, (Maybe ExitCode, Bool))
    -> IO (ProcessHandle__, (Maybe ExitCode, Bool))
    forall (m :: * -> *) a. Monad m => a -> m a
    return (ProcessHandle__
    p_, (Maybe ExitCode
    forall a. Maybe a
    Nothing, Bool
    False))
                       else do
                            Pid -> IO ()
    closePHANDLE Pid
    h
                            let e :: ExitCode
    e  | CInt
    code CInt -> CInt -> Bool
    forall a. Eq a => a -> a -> Bool
    == CInt
    0 = ExitCode
    ExitSuccess
                                   | Bool
    otherwise = Int -> ExitCode
    ExitFailure (CInt -> Int
    forall a b. (Integral a, Num b) => a -> b
    fromIntegral CInt
    code)
                            (ProcessHandle__, (Maybe ExitCode, Bool))
    -> IO (ProcessHandle__, (Maybe ExitCode, Bool))
    forall (m :: * -> *) a. Monad m => a -> m a
    return (ExitCode -> ProcessHandle__
    ClosedHandle ExitCode
    e, (ExitCode -> Maybe ExitCode
    forall a. a -> Maybe a
    Just ExitCode
    e, Bool
    True))
      case Maybe ExitCode
    m_e of
        Just ExitCode
    e | Bool
    was_open Bool -> Bool -> Bool
    && Bool
    delegating_ctlc -> ExitCode -> IO ()
    endDelegateControlC ExitCode
    e
        Maybe ExitCode
    _                                    -> () -> IO ()
    forall (m :: * -> *) a. Monad m => a -> m a
    return ()
      Maybe ExitCode -> IO (Maybe ExitCode)
    forall (m :: * -> *) a. Monad m => a -> m a
    return Maybe ExitCode
    m_e
        where getHandle :: ProcessHandle__ -> Maybe PHANDLE
              getHandle :: ProcessHandle__ -> Maybe Pid
    getHandle (OpenHandle        Pid
    h) = Pid -> Maybe Pid
    forall a. a -> Maybe a
    Just Pid
    h
              getHandle (ClosedHandle      ExitCode
    _) = Maybe Pid
    forall a. Maybe a
    Nothing
              getHandle (OpenExtHandle   Pid
    h Pid
    _) = Pid -> Maybe Pid
    forall a. a -> Maybe a
    Just Pid
    h

              -- If somebody is currently holding the waitpid lock, we don't want to
              -- accidentally remove the pid from the process table.
              -- Try acquiring the waitpid lock. If it is held, we are done
              -- since that means the process is still running and we can return
              -- `Nothing`. If it is not held, acquire it so we can run the
              -- (non-blocking) call to `waitpid` without worrying about any
              -- other threads calling it at the same time.
              tryLockWaitpid :: IO (Maybe ExitCode) -> IO (Maybe ExitCode)
              tryLockWaitpid :: IO (Maybe ExitCode) -> IO (Maybe ExitCode)
    tryLockWaitpid IO (Maybe ExitCode)
    action = IO (Maybe ())
    -> (Maybe () -> IO ())
    -> (Maybe () -> IO (Maybe ExitCode))
    -> IO (Maybe ExitCode)
    forall a b c. IO a -> (a -> IO b) -> (a -> IO c) -> IO c
    bracket IO (Maybe ())
    acquire Maybe () -> IO ()
    release Maybe () -> IO (Maybe ExitCode)
    between
                where
                  acquire :: IO (Maybe ())
    acquire   = MVar () -> IO (Maybe ())
    forall a. MVar a -> IO (Maybe a)
    tryTakeMVar (ProcessHandle -> MVar ()
    waitpidLock ProcessHandle
    ph)
                  release :: Maybe () -> IO ()
    release Maybe ()
    m = case Maybe ()
    m of
                    Maybe ()
    Nothing -> () -> IO ()
    forall (m :: * -> *) a. Monad m => a -> m a
    return ()
                    Just () -> MVar () -> () -> IO ()
    forall a. MVar a -> a -> IO ()
    putMVar (ProcessHandle -> MVar ()
    waitpidLock ProcessHandle
    ph) ()
                  between :: Maybe () -> IO (Maybe ExitCode)
    between Maybe ()
    m = case Maybe ()
    m of
                    Maybe ()
    Nothing -> Maybe ExitCode -> IO (Maybe ExitCode)
    forall (m :: * -> *) a. Monad m => a -> m a
    return Maybe ExitCode
    forall a. Maybe a
    Nothing
                    Just () -> IO (Maybe ExitCode)
    action

    -- ----------------------------------------------------------------------------
    -- terminateProcess

    -- | Attempts to terminate the specified process.  This function should
    -- not be used under normal circumstances - no guarantees are given regarding
    -- how cleanly the process is terminated.  To check whether the process
    -- has indeed terminated, use 'getProcessExitCode'.
    --
    -- On Unix systems, 'terminateProcess' sends the process the SIGTERM signal.
    -- On Windows systems, if `use_process_jobs` is `True` then the Win32 @TerminateJobObject@
    -- function is called to kill all processes associated with the job and passing the
    -- exit code of 1 to each of them. Otherwise if `use_process_jobs` is `False` then the
    -- Win32 @TerminateProcess@ function is called, passing an exit code of 1.
    --
    -- Note: on Windows, if the process was a shell command created by
    -- 'createProcess' with 'shell', or created by 'runCommand' or
    -- 'runInteractiveCommand', then 'terminateProcess' will only
    -- terminate the shell, not the command itself.  On Unix systems, both
    -- processes are in a process group and will be terminated together.

    terminateProcess :: ProcessHandle -> IO ()
    terminateProcess :: ProcessHandle -> IO ()
    terminateProcess ProcessHandle
    ph = do
      ProcessHandle -> (ProcessHandle__ -> IO ()) -> IO ()
    forall a. ProcessHandle -> (ProcessHandle__ -> IO a) -> IO a
    withProcessHandle ProcessHandle
    ph ((ProcessHandle__ -> IO ()) -> IO ())
    -> (ProcessHandle__ -> IO ()) -> IO ()
    forall a b. (a -> b) -> a -> b
    $ \ProcessHandle__
    p_ ->
        case ProcessHandle__
    p_ of
          ClosedHandle  ExitCode
    _ -> () -> IO ()
    forall (m :: * -> *) a. Monad m => a -> m a
    return ()
    #if defined(WINDOWS)
          OpenExtHandle{} -> terminateJobUnsafe p_ 1 >> return ()
    #else
          OpenExtHandle{} -> String -> IO ()
    forall a. HasCallStack => String -> a
    error String
    "terminateProcess with OpenExtHandle should not happen on POSIX."
    #endif
          OpenHandle    Pid
    h -> do
            String -> IO CInt -> IO ()
    forall a. (Eq a, Num a) => String -> IO a -> IO ()
    throwErrnoIfMinus1Retry_ String
    "terminateProcess" (IO CInt -> IO ()) -> IO CInt -> IO ()
    forall a b. (a -> b) -> a -> b
    $ Pid -> IO CInt
    c_terminateProcess Pid
    h
            () -> IO ()
    forall (m :: * -> *) a. Monad m => a -> m a
    return ()
            -- does not close the handle, we might want to try terminating it
            -- again, or get its exit code.

    -- ----------------------------------------------------------------------------
    -- Interface to C bits

    foreign import ccall unsafe "terminateProcess"
      c_terminateProcess
            :: PHANDLE
            -> IO CInt

    foreign import ccall unsafe "getProcessExitCode"
      c_getProcessExitCode
            :: PHANDLE
            -> Ptr CInt
            -> IO CInt

    foreign import ccall interruptible "waitForProcess" -- NB. safe - can block
      c_waitForProcess
            :: PHANDLE
            -> Ptr CInt
            -> IO CInt

    -- ----------------------------------------------------------------------------
    -- Old deprecated variants
    -- ----------------------------------------------------------------------------

    -- TODO: We're not going to mark these functions as DEPRECATED immediately in
    -- process-1.2.0.0. That's because some of their replacements have not been
    -- around for all that long. But they should eventually be marked with a
    -- suitable DEPRECATED pragma after a release or two.

    -- ----------------------------------------------------------------------------
    -- runCommand

    --TODO: in a later release {-# DEPRECATED runCommand "Use 'spawnCommand' instead" #-}

    {- | Runs a command using the shell.
     -}
    runCommand
      :: String
      -> IO ProcessHandle

    runCommand :: String -> IO ProcessHandle
    runCommand String
    string = do
      (Maybe Handle
    _,Maybe Handle
    _,Maybe Handle
    _,ProcessHandle
    ph) <- String
    -> CreateProcess
    -> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    createProcess_ String
    "runCommand" (String -> CreateProcess
    shell String
    string)
      ProcessHandle -> IO ProcessHandle
    forall (m :: * -> *) a. Monad m => a -> m a
    return ProcessHandle
    ph

    -- ----------------------------------------------------------------------------
    -- runProcess

    --TODO: in a later release {-# DEPRECATED runProcess "Use 'spawnProcess' or 'createProcess' instead" #-}

    {- | Runs a raw command, optionally specifying 'Handle's from which to
         take the @stdin@, @stdout@ and @stderr@ channels for the new
         process (otherwise these handles are inherited from the current
         process).

         Any 'Handle's passed to 'runProcess' are placed immediately in the
         closed state.

         Note: consider using the more general 'createProcess' instead of
         'runProcess'.
    -}
    runProcess
      :: FilePath                   -- ^ Filename of the executable (see 'RawCommand' for details)
      -> [String]                   -- ^ Arguments to pass to the executable
      -> Maybe FilePath             -- ^ Optional path to the working directory
      -> Maybe [(String,String)]    -- ^ Optional environment (otherwise inherit)
      -> Maybe Handle               -- ^ Handle to use for @stdin@ (Nothing => use existing @stdin@)
      -> Maybe Handle               -- ^ Handle to use for @stdout@ (Nothing => use existing @stdout@)
      -> Maybe Handle               -- ^ Handle to use for @stderr@ (Nothing => use existing @stderr@)
      -> IO ProcessHandle

    runProcess :: String
    -> [String]
    -> Maybe String
    -> Maybe [(String, String)]
    -> Maybe Handle
    -> Maybe Handle
    -> Maybe Handle
    -> IO ProcessHandle
    runProcess String
    cmd [String]
    args Maybe String
    mb_cwd Maybe [(String, String)]
    mb_env Maybe Handle
    mb_stdin Maybe Handle
    mb_stdout Maybe Handle
    mb_stderr = do
      (Maybe Handle
    _,Maybe Handle
    _,Maybe Handle
    _,ProcessHandle
    ph) <-
          String
    -> CreateProcess
    -> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    createProcess_ String
    "runProcess"
             (String -> [String] -> CreateProcess
    proc String
    cmd [String]
    args){ cwd :: Maybe String
    cwd = Maybe String
    mb_cwd,
                              env :: Maybe [(String, String)]
    env = Maybe [(String, String)]
    mb_env,
                              std_in :: StdStream
    std_in  = Maybe Handle -> StdStream
    mbToStd Maybe Handle
    mb_stdin,
                              std_out :: StdStream
    std_out = Maybe Handle -> StdStream
    mbToStd Maybe Handle
    mb_stdout,
                              std_err :: StdStream
    std_err = Maybe Handle -> StdStream
    mbToStd Maybe Handle
    mb_stderr }
      Maybe Handle -> IO ()
    maybeClose Maybe Handle
    mb_stdin
      Maybe Handle -> IO ()
    maybeClose Maybe Handle
    mb_stdout
      Maybe Handle -> IO ()
    maybeClose Maybe Handle
    mb_stderr
      ProcessHandle -> IO ProcessHandle
    forall (m :: * -> *) a. Monad m => a -> m a
    return ProcessHandle
    ph
     where
      maybeClose :: Maybe Handle -> IO ()
      maybeClose :: Maybe Handle -> IO ()
    maybeClose (Just  Handle
    hdl)
        | Handle
    hdl Handle -> Handle -> Bool
    forall a. Eq a => a -> a -> Bool
    /= Handle
    stdin Bool -> Bool -> Bool
    && Handle
    hdl Handle -> Handle -> Bool
    forall a. Eq a => a -> a -> Bool
    /= Handle
    stdout Bool -> Bool -> Bool
    && Handle
    hdl Handle -> Handle -> Bool
    forall a. Eq a => a -> a -> Bool
    /= Handle
    stderr = Handle -> IO ()
    hClose Handle
    hdl
      maybeClose Maybe Handle
    _ = () -> IO ()
    forall (m :: * -> *) a. Monad m => a -> m a
    return ()

      mbToStd :: Maybe Handle -> StdStream
      mbToStd :: Maybe Handle -> StdStream
    mbToStd Maybe Handle
    Nothing    = StdStream
    Inherit
      mbToStd (Just Handle
    hdl) = Handle -> StdStream
    UseHandle Handle
    hdl

    -- ----------------------------------------------------------------------------
    -- runInteractiveCommand

    --TODO: in a later release {-# DEPRECATED runInteractiveCommand "Use 'createProcess' instead" #-}

    {- | Runs a command using the shell, and returns 'Handle's that may
         be used to communicate with the process via its @stdin@, @stdout@,
         and @stderr@ respectively.
    -}
    runInteractiveCommand
      :: String
      -> IO (Handle,Handle,Handle,ProcessHandle)

    runInteractiveCommand :: String -> IO (Handle, Handle, Handle, ProcessHandle)
    runInteractiveCommand String
    string =
      String
    -> CreateProcess -> IO (Handle, Handle, Handle, ProcessHandle)
    runInteractiveProcess1 String
    "runInteractiveCommand" (String -> CreateProcess
    shell String
    string)

    -- ----------------------------------------------------------------------------
    -- runInteractiveProcess

    --TODO: in a later release {-# DEPRECATED runInteractiveCommand "Use 'createProcess' instead" #-}

    {- | Runs a raw command, and returns 'Handle's that may be used to communicate
         with the process via its @stdin@, @stdout@ and @stderr@ respectively.

        For example, to start a process and feed a string to its stdin:

    >   (inp,out,err,pid) <- runInteractiveProcess "..."
    >   forkIO (hPutStr inp str)
    -}
    runInteractiveProcess
      :: FilePath                   -- ^ Filename of the executable (see 'RawCommand' for details)
      -> [String]                   -- ^ Arguments to pass to the executable
      -> Maybe FilePath             -- ^ Optional path to the working directory
      -> Maybe [(String,String)]    -- ^ Optional environment (otherwise inherit)
      -> IO (Handle,Handle,Handle,ProcessHandle)

    runInteractiveProcess :: String
    -> [String]
    -> Maybe String
    -> Maybe [(String, String)]
    -> IO (Handle, Handle, Handle, ProcessHandle)
    runInteractiveProcess String
    cmd [String]
    args Maybe String
    mb_cwd Maybe [(String, String)]
    mb_env = do
      String
    -> CreateProcess -> IO (Handle, Handle, Handle, ProcessHandle)
    runInteractiveProcess1 String
    "runInteractiveProcess"
            (String -> [String] -> CreateProcess
    proc String
    cmd [String]
    args){ cwd :: Maybe String
    cwd = Maybe String
    mb_cwd, env :: Maybe [(String, String)]
    env = Maybe [(String, String)]
    mb_env }

    runInteractiveProcess1
      :: String
      -> CreateProcess
      -> IO (Handle,Handle,Handle,ProcessHandle)
    runInteractiveProcess1 :: String
    -> CreateProcess -> IO (Handle, Handle, Handle, ProcessHandle)
    runInteractiveProcess1 String
    fun CreateProcess
    cmd = do
      (Maybe Handle
    mb_in, Maybe Handle
    mb_out, Maybe Handle
    mb_err, ProcessHandle
    p) <-
          String
    -> CreateProcess
    -> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    createProcess_ String
    fun
               CreateProcess
    cmd{ std_in :: StdStream
    std_in  = StdStream
    CreatePipe,
                    std_out :: StdStream
    std_out = StdStream
    CreatePipe,
                    std_err :: StdStream
    std_err = StdStream
    CreatePipe }
      (Handle, Handle, Handle, ProcessHandle)
    -> IO (Handle, Handle, Handle, ProcessHandle)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (Maybe Handle -> Handle
    forall a. HasCallStack => Maybe a -> a
    fromJust Maybe Handle
    mb_in, Maybe Handle -> Handle
    forall a. HasCallStack => Maybe a -> a
    fromJust Maybe Handle
    mb_out, Maybe Handle -> Handle
    forall a. HasCallStack => Maybe a -> a
    fromJust Maybe Handle
    mb_err, ProcessHandle
    p)

    -- ---------------------------------------------------------------------------
    -- system & rawSystem

    --TODO: in a later release {-# DEPRECATED system "Use 'callCommand' (or 'spawnCommand' and 'waitForProcess') instead" #-}

    {-|
    Computation @system cmd@ returns the exit code produced when the
    operating system runs the shell command @cmd@.

    This computation may fail with one of the following
    'System.IO.Error.IOErrorType' exceptions:

    [@PermissionDenied@]
    The process has insufficient privileges to perform the operation.

    [@ResourceExhausted@]
    Insufficient resources are available to perform the operation.

    [@UnsupportedOperation@]
    The implementation does not support system calls.

    On Windows, 'system' passes the command to the Windows command
    interpreter (@CMD.EXE@ or @COMMAND.COM@), hence Unixy shell tricks
    will not work.

    On Unix systems, see 'waitForProcess' for the meaning of exit codes
    when the process died as the result of a signal.
    -}
    system :: String -> IO ExitCode
    system :: String -> IO ExitCode
    system String
    "" = IOException -> IO ExitCode
    forall a. IOException -> IO a
    ioException (IOException -> String -> IOException
    ioeSetErrorString (IOErrorType
    -> String -> Maybe Handle -> Maybe String -> IOException
    mkIOError IOErrorType
    InvalidArgument String
    "system" Maybe Handle
    forall a. Maybe a
    Nothing Maybe String
    forall a. Maybe a
    Nothing) String
    "null command")
    system String
    str = do
      (Maybe Handle
    _,Maybe Handle
    _,Maybe Handle
    _,ProcessHandle
    p) <- String
    -> CreateProcess
    -> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    createProcess_ String
    "system" (String -> CreateProcess
    shell String
    str) { delegate_ctlc :: Bool
    delegate_ctlc = Bool
    True }
      ProcessHandle -> IO ExitCode
    waitForProcess ProcessHandle
    p

    --TODO: in a later release {-# DEPRECATED rawSystem "Use 'callProcess' (or 'spawnProcess' and 'waitForProcess') instead" #-}

    {-|
    The computation @'rawSystem' /cmd/ /args/@ runs the operating system command
    @/cmd/@ in such a way that it receives as arguments the @/args/@ strings
    exactly as given, with no funny escaping or shell meta-syntax expansion.
    It will therefore behave more portably between operating systems than 'system'.

    The return codes and possible failures are the same as for 'system'.
    -}
    rawSystem :: String -> [String] -> IO ExitCode
    rawSystem :: String -> [String] -> IO ExitCode
    rawSystem String
    cmd [String]
    args = do
      (Maybe Handle
    _,Maybe Handle
    _,Maybe Handle
    _,ProcessHandle
    p) <- String
    -> CreateProcess
    -> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
    createProcess_ String
    "rawSystem" (String -> [String] -> CreateProcess
    proc String
    cmd [String]
    args) { delegate_ctlc :: Bool
    delegate_ctlc = Bool
    True }
      ProcessHandle -> IO ExitCode
    waitForProcess ProcessHandle
    p