    {-# LINE 1 "Network/Socket.hsc" #-}
    {-# LANGUAGE CPP, ScopedTypeVariables #-}
    {-# LINE 2 "Network/Socket.hsc" #-}
    {-# OPTIONS_GHC -fno-warn-orphans #-}
    -----------------------------------------------------------------------------
    -- |
    -- Module      :  Network.Socket
    -- Copyright   :  (c) The University of Glasgow 2001
    -- License     :  BSD-style (see the file libraries/network/LICENSE)
    --
    -- Maintainer  :  libraries@haskell.org
    -- Stability   :  provisional
    -- Portability :  portable
    --
    -- The "Network.Socket" module is for when you want full control over
    -- sockets.  Essentially the entire C socket API is exposed through
    -- this module; in general the operations follow the behaviour of the C
    -- functions of the same name (consult your favourite Unix networking book).
    --
    -- A higher level interface to networking operations is provided
    -- through the module "Network".
    --
    -----------------------------------------------------------------------------

    {-# LINE 24 "Network/Socket.hsc" #-}

    -- In order to process this file, you need to have CALLCONV defined.

    module Network.Socket
        (
        -- * Types
          Socket(..)
        , Family(..)
        , isSupportedFamily
        , SocketType(..)
        , isSupportedSocketType
        , SockAddr(..)
        , isSupportedSockAddr
        , SocketStatus(..)
        , HostAddress
        , hostAddressToTuple
        , tupleToHostAddress

    {-# LINE 42 "Network/Socket.hsc" #-}
        , HostAddress6
        , hostAddress6ToTuple
        , tupleToHostAddress6
        , FlowInfo
        , ScopeID

    {-# LINE 48 "Network/Socket.hsc" #-}
        , htonl
        , ntohl
        , ShutdownCmd(..)
        , ProtocolNumber
        , defaultProtocol
        , PortNumber(..)
        -- PortNumber is used non-abstractly in Network.BSD.  ToDo: remove
        -- this use and make the type abstract.

        -- * Address operations

        , HostName
        , ServiceName

    {-# LINE 63 "Network/Socket.hsc" #-}
        , AddrInfo(..)

        , AddrInfoFlag(..)
        , addrInfoFlagImplemented

        , defaultHints

        , getAddrInfo

        , NameInfoFlag(..)

        , getNameInfo

    {-# LINE 76 "Network/Socket.hsc" #-}

        -- * Socket operations
        , socket

    {-# LINE 80 "Network/Socket.hsc" #-}
        , socketPair

    {-# LINE 82 "Network/Socket.hsc" #-}
        , connect
        , bind
        , listen
        , accept
        , getPeerName
        , getSocketName

    {-# LINE 90 "Network/Socket.hsc" #-}
        -- get the credentials of our domain socket peer.
        , getPeerCred

    {-# LINE 95 "Network/Socket.hsc" #-}

    {-# LINE 96 "Network/Socket.hsc" #-}

        , socketPort

        , socketToHandle

        -- ** Sending and receiving data
        -- *** Sending and receiving with String
        -- $sendrecv
        , send
        , sendTo
        , recv
        , recvFrom
        , recvLen

        -- *** Sending and receiving with a buffer
        , sendBuf
        , recvBuf
        , sendBufTo
        , recvBufFrom

        -- ** Misc
        , inet_addr
        , inet_ntoa

        , shutdown
        , close

        -- ** Predicates on sockets
        , isConnected
        , isBound
        , isListening
        , isReadable
        , isWritable

        -- * Socket options
        , SocketOption(..)
        , isSupportedSocketOption
        , getSocketOption
        , setSocketOption

        -- * File descriptor transmission

    {-# LINE 138 "Network/Socket.hsc" #-}
        , sendFd
        , recvFd

    {-# LINE 142 "Network/Socket.hsc" #-}

        -- * Special constants
        , aNY_PORT
        , iNADDR_ANY

    {-# LINE 147 "Network/Socket.hsc" #-}
        , iN6ADDR_ANY

    {-# LINE 149 "Network/Socket.hsc" #-}
        , sOMAXCONN
        , sOL_SOCKET

    {-# LINE 152 "Network/Socket.hsc" #-}
        , sCM_RIGHTS

    {-# LINE 154 "Network/Socket.hsc" #-}
        , maxListenQueue

        -- * Initialisation
        , withSocketsDo

        -- * Very low level operations
        -- in case you ever want to get at the underlying file descriptor..
        , fdSocket
        , mkSocket
        , setNonBlockIfNeeded

        -- * Deprecated aliases
        -- $deprecated-aliases
        , bindSocket
        , sClose
        , sIsConnected
        , sIsBound
        , sIsListening
        , sIsReadable
        , sIsWritable

        -- * Internal

        -- | The following are exported ONLY for use in the BSD module and
        -- should not be used anywhere else.

        , packFamily
        , unpackFamily
        , packSocketType
        ) where

    import Data.Bits
    import Data.Functor
    import Data.List (foldl')
    import Data.Maybe (isJust)
    import Data.Word (Word8, Word32)
    import Foreign.Ptr (Ptr, castPtr, nullPtr)
    import Foreign.Storable (Storable(..))
    import Foreign.C.Error
    import Foreign.C.String (CString, withCString, withCStringLen, peekCString, peekCStringLen)
    import Foreign.C.Types (CUInt, CChar)
    import Foreign.C.Types (CInt(..), CSize(..))
    import Foreign.Marshal.Alloc ( alloca, allocaBytes )
    import Foreign.Marshal.Array ( peekArray )
    import Foreign.Marshal.Utils ( maybeWith, with )

    import System.IO
    import Control.Monad (liftM, when)

    import Control.Concurrent.MVar
    import Data.Typeable
    import System.IO.Error

    import GHC.Conc (threadWaitRead, threadWaitWrite)
    #if MIN_VERSION_base(4,3,1)
    import GHC.Conc (closeFdWith)
    #endif

    {-# LINE 217 "Network/Socket.hsc" #-}

    {-# LINE 220 "Network/Socket.hsc" #-}
    import qualified GHC.IO.Device
    import GHC.IO.Handle.FD
    import GHC.IO.Exception
    import GHC.IO
    import qualified System.Posix.Internals

    import Network.Socket.Internal
    import Network.Socket.Types

    import Prelude -- Silence AMP warnings

    -- | Either a host name e.g., @\"haskell.org\"@ or a numeric host
    -- address string consisting of a dotted decimal IPv4 address or an
    -- IPv6 address e.g., @\"192.168.0.1\"@.
    type HostName       = String
    type ServiceName    = String

    -- ----------------------------------------------------------------------------
    -- On Windows, our sockets are not put in non-blocking mode (non-blocking
    -- is not supported for regular file descriptors on Windows, and it would
    -- be a pain to support it only for sockets).  So there are two cases:
    --
    --  - the threaded RTS uses safe calls for socket operations to get
    --    non-blocking I/O, just like the rest of the I/O library
    --
    --  - with the non-threaded RTS, only some operations on sockets will be
    --    non-blocking.  Reads and writes go through the normal async I/O
    --    system.  accept() uses asyncDoProc so is non-blocking.  A handful
    --    of others (recvFrom, sendFd, recvFd) will block all threads - if this
    --    is a problem, -threaded is the workaround.
    --
    #if defined(mingw32_HOST_OS)
    #define SAFE_ON_WIN safe
    #else
    #define SAFE_ON_WIN unsafe
    #endif

    -----------------------------------------------------------------------------
    -- Socket types

    {-# LINE 265 "Network/Socket.hsc" #-}

    -- | Smart constructor for constructing a 'Socket'. It should only be
    -- called once for every new file descriptor. The caller must make
    -- sure that the socket is in non-blocking mode. See
    -- 'setNonBlockIfNeeded'.
    mkSocket :: CInt
             -> Family
             -> SocketType
             -> ProtocolNumber
             -> SocketStatus
             -> IO Socket
    mkSocket fd fam sType pNum stat = do
       mStat <- newMVar stat
       withSocketsDo $ return ()
       return (MkSocket fd fam sType pNum mStat)

    fdSocket :: Socket -> CInt
    fdSocket (MkSocket fd _ _ _ _) = fd

    -- | This is the default protocol for a given service.
    defaultProtocol :: ProtocolNumber
    defaultProtocol = 0

    -----------------------------------------------------------------------------
    -- SockAddr

    instance Show SockAddr where

    {-# LINE 294 "Network/Socket.hsc" #-}
      showsPrec _ (SockAddrUnix str) = showString str

    {-# LINE 296 "Network/Socket.hsc" #-}
      showsPrec _ (SockAddrInet port ha)
       = showString (unsafePerformIO (inet_ntoa ha))
       . showString ":"
       . shows port

    {-# LINE 301 "Network/Socket.hsc" #-}
      showsPrec _ addr@(SockAddrInet6 port _ _ _)
       = showChar '['
       . showString (unsafePerformIO $
                     fst `liftM` getNameInfo [NI_NUMERICHOST] True False addr >>=
                     maybe (fail "showsPrec: impossible internal error") return)
       . showString "]:"
       . shows port

    {-# LINE 309 "Network/Socket.hsc" #-}

    {-# LINE 310 "Network/Socket.hsc" #-}
      showsPrec _ (SockAddrCan ifidx) = shows ifidx

    {-# LINE 312 "Network/Socket.hsc" #-}

    -----------------------------------------------------------------------------
    -- Connection Functions

    -- In the following connection and binding primitives.  The names of
    -- the equivalent C functions have been preserved where possible. It
    -- should be noted that some of these names used in the C library,
    -- \tr{bind} in particular, have a different meaning to many Haskell
    -- programmers and have thus been renamed by appending the prefix
    -- Socket.

    -- | Create a new socket using the given address family, socket type
    -- and protocol number.  The address family is usually 'AF_INET',
    -- 'AF_INET6', or 'AF_UNIX'.  The socket type is usually 'Stream' or
    -- 'Datagram'.  The protocol number is usually 'defaultProtocol'.
    -- If 'AF_INET6' is used and the socket type is 'Stream' or 'Datagram',
    -- the 'IPv6Only' socket option is set to 0 so that both IPv4 and IPv6
    -- can be handled with one socket.
    --
    -- >>> let hints = defaultHints { addrFlags = [AI_NUMERICHOST, AI_NUMERICSERV], addrSocketType = Stream }
    -- >>> addr:_ <- getAddrInfo (Just hints) (Just "127.0.0.1") (Just "5000")
    -- >>> sock@(MkSocket _ fam stype _ _) <- socket (addrFamily addr) (addrSocketType addr) (addrProtocol addr)
    -- >>> fam
    -- AF_INET
    -- >>> stype
    -- Stream
    -- >>> bind sock (addrAddress addr)
    -- >>> getSocketName sock
    -- 127.0.0.1:5000
    socket :: Family         -- Family Name (usually AF_INET)
           -> SocketType     -- Socket Type (usually Stream)
           -> ProtocolNumber -- Protocol Number (getProtocolByName to find value)
           -> IO Socket      -- Unconnected Socket
    socket family stype protocol = do
        c_stype <- packSocketTypeOrThrow "socket" stype
        fd <- throwSocketErrorIfMinus1Retry "Network.Socket.socket" $
                    c_socket (packFamily family) c_stype protocol
        setNonBlockIfNeeded fd
        socket_status <- newMVar NotConnected
        withSocketsDo $ return ()
        let sock = MkSocket fd family stype protocol socket_status

    {-# LINE 354 "Network/Socket.hsc" #-}
        -- The default value of the IPv6Only option is platform specific,
        -- so we explicitly set it to 0 to provide a common default.

    {-# LINE 362 "Network/Socket.hsc" #-}
        when (family == AF_INET6 && (stype == Stream || stype == Datagram)) $
          setSocketOption sock IPv6Only 0 `onException` close sock

    {-# LINE 365 "Network/Socket.hsc" #-}

    {-# LINE 366 "Network/Socket.hsc" #-}
        return sock

    -- | Build a pair of connected socket objects using the given address
    -- family, socket type, and protocol number.  Address family, socket
    -- type, and protocol number are as for the 'socket' function above.
    -- Availability: Unix.

    {-# LINE 373 "Network/Socket.hsc" #-}
    socketPair :: Family              -- Family Name (usually AF_INET or AF_INET6)
               -> SocketType          -- Socket Type (usually Stream)
               -> ProtocolNumber      -- Protocol Number
               -> IO (Socket, Socket) -- unnamed and connected.
    socketPair family stype protocol = do
        allocaBytes (2 * sizeOf (1 :: CInt)) $ \ fdArr -> do
        c_stype <- packSocketTypeOrThrow "socketPair" stype
        _rc <- throwSocketErrorIfMinus1Retry "Network.Socket.socketpair" $
                    c_socketpair (packFamily family) c_stype protocol fdArr
        [fd1,fd2] <- peekArray 2 fdArr
        s1 <- mkNonBlockingSocket fd1
        s2 <- mkNonBlockingSocket fd2
        return (s1,s2)
      where
        mkNonBlockingSocket fd = do
           setNonBlockIfNeeded fd
           stat <- newMVar Connected
           withSocketsDo $ return ()
           return (MkSocket fd family stype protocol stat)

    foreign import ccall unsafe "socketpair"
      c_socketpair :: CInt -> CInt -> CInt -> Ptr CInt -> IO CInt

    {-# LINE 396 "Network/Socket.hsc" #-}

    -- | Set the socket to nonblocking, if applicable to this platform.
    --
    -- Depending on the platform this is required when using sockets from file
    -- descriptors that are passed in through 'recvFd' or other means.
    setNonBlockIfNeeded :: CInt -> IO ()
    setNonBlockIfNeeded fd =
        System.Posix.Internals.setNonBlockingFD fd True

    -----------------------------------------------------------------------------
    -- Binding a socket

    -- | Bind the socket to an address. The socket must not already be
    -- bound.  The 'Family' passed to @bind@ must be the
    -- same as that passed to 'socket'.  If the special port number
    -- 'aNY_PORT' is passed then the system assigns the next available
    -- use port.
    bind :: Socket    -- Unconnected Socket
               -> SockAddr  -- Address to Bind to
               -> IO ()
    bind (MkSocket s _family _stype _protocol socketStatus) addr = do
     modifyMVar_ socketStatus $ \ status -> do
     if status /= NotConnected
      then
       ioError $ userError $
         "Network.Socket.bind: can't bind to socket with status " ++ show status
      else do
       withSockAddr addr $ \p_addr sz -> do
       _status <- throwSocketErrorIfMinus1Retry "Network.Socket.bind" $
         c_bind s p_addr (fromIntegral sz)
       return Bound

    -----------------------------------------------------------------------------
    -- Connecting a socket

    -- | Connect to a remote socket at address.
    connect :: Socket    -- Unconnected Socket
            -> SockAddr  -- Socket address stuff
            -> IO ()
    connect sock@(MkSocket s _family _stype _protocol socketStatus) addr = withSocketsDo $ do
     modifyMVar_ socketStatus $ \currentStatus -> do
     if currentStatus /= NotConnected && currentStatus /= Bound
      then
        ioError $ userError $
          errLoc ++ ": can't connect to socket with status " ++ show currentStatus
      else do
        withSockAddr addr $ \p_addr sz -> do

        let connectLoop = do
               r <- c_connect s p_addr (fromIntegral sz)
               if r == -1
                   then do

    {-# LINE 449 "Network/Socket.hsc" #-}
                       err <- getErrno
                       case () of
                         _ | err == eINTR       -> connectLoop
                         _ | err == eINPROGRESS -> connectBlocked
    --                   _ | err == eAGAIN      -> connectBlocked
                         _otherwise             -> throwSocketError errLoc

    {-# LINE 458 "Network/Socket.hsc" #-}
                   else return ()

            connectBlocked = do
               threadWaitWrite (fromIntegral s)
               err <- getSocketOption sock SoError
               if (err == 0)
                    then return ()
                    else throwSocketErrorCode errLoc (fromIntegral err)

        connectLoop
        return Connected
     where
       errLoc = "Network.Socket.connect: " ++ show sock

    -----------------------------------------------------------------------------
    -- Listen

    -- | Listen for connections made to the socket.  The second argument
    -- specifies the maximum number of queued connections and should be at
    -- least 1; the maximum value is system-dependent (usually 5).
    listen :: Socket  -- Connected & Bound Socket
           -> Int     -- Queue Length
           -> IO ()
    listen (MkSocket s _family _stype _protocol socketStatus) backlog = do
     modifyMVar_ socketStatus $ \ status -> do
     if status /= Bound
       then
         ioError $ userError $
           "Network.Socket.listen: can't listen on socket with status " ++ show status
       else do
         throwSocketErrorIfMinus1Retry_ "Network.Socket.listen" $
           c_listen s (fromIntegral backlog)
         return Listening

    -----------------------------------------------------------------------------
    -- Accept
    --
    -- A call to `accept' only returns when data is available on the given
    -- socket, unless the socket has been set to non-blocking.  It will
    -- return a new socket which should be used to read the incoming data and
    -- should then be closed. Using the socket returned by `accept' allows
    -- incoming requests to be queued on the original socket.

    -- | Accept a connection.  The socket must be bound to an address and
    -- listening for connections.  The return value is a pair @(conn,
    -- address)@ where @conn@ is a new socket object usable to send and
    -- receive data on the connection, and @address@ is the address bound
    -- to the socket on the other end of the connection.
    accept :: Socket                        -- Queue Socket
           -> IO (Socket,                   -- Readable Socket
                  SockAddr)                 -- Peer details

    accept sock@(MkSocket s family stype protocol status) = do
     currentStatus <- readMVar status
     okay <- isAcceptable sock
     if not okay
       then
         ioError $ userError $
           "Network.Socket.accept: can't accept socket (" ++
             show (family, stype, protocol) ++ ") with status " ++
             show currentStatus
       else do
         let sz = sizeOfSockAddrByFamily family
         allocaBytes sz $ \ sockaddr -> do

    {-# LINE 537 "Network/Socket.hsc" #-}
         with (fromIntegral sz) $ \ ptr_len -> do

    {-# LINE 539 "Network/Socket.hsc" #-}
         new_sock <- throwSocketErrorIfMinus1RetryMayBlock "Network.Socket.accept"
                            (threadWaitRead (fromIntegral s))
                            (c_accept4 s sockaddr ptr_len (2048))
    {-# LINE 542 "Network/Socket.hsc" #-}

    {-# LINE 547 "Network/Socket.hsc" #-}

    {-# LINE 548 "Network/Socket.hsc" #-}
         addr <- peekSockAddr sockaddr
         new_status <- newMVar Connected
         return ((MkSocket new_sock family stype protocol new_status), addr)

    {-# LINE 562 "Network/Socket.hsc" #-}

    -----------------------------------------------------------------------------
    -- ** Sending and receiving data

    -- $sendrecv
    --
    -- Do not use the @send@ and @recv@ functions defined in this section
    -- in new code, as they incorrectly represent binary data as a Unicode
    -- string.  As a result, these functions are inefficient and may lead
    -- to bugs in the program.  Instead use the @send@ and @recv@
    -- functions defined in the "Network.Socket.ByteString" module.

    -----------------------------------------------------------------------------
    -- sendTo & recvFrom

    -- | Send data to the socket.  The recipient can be specified
    -- explicitly, so the socket need not be in a connected state.
    -- Returns the number of bytes sent.  Applications are responsible for
    -- ensuring that all data has been sent.
    --
    -- NOTE: blocking on Windows unless you compile with -threaded (see
    -- GHC ticket #1129)
    {-# WARNING sendTo "Use sendTo defined in \"Network.Socket.ByteString\"" #-}
    sendTo :: Socket        -- (possibly) bound/connected Socket
           -> String        -- Data to send
           -> SockAddr
           -> IO Int        -- Number of Bytes sent
    sendTo sock xs addr = do
     withCStringLen xs $ \(str, len) -> do
       sendBufTo sock str len addr

    -- | Send data to the socket.  The recipient can be specified
    -- explicitly, so the socket need not be in a connected state.
    -- Returns the number of bytes sent.  Applications are responsible for
    -- ensuring that all data has been sent.
    sendBufTo :: Socket            -- (possibly) bound/connected Socket
              -> Ptr a -> Int  -- Data to send
              -> SockAddr
              -> IO Int            -- Number of Bytes sent
    sendBufTo sock@(MkSocket s _family _stype _protocol _status) ptr nbytes addr = do
     withSockAddr addr $ \p_addr sz -> do
       liftM fromIntegral $
         throwSocketErrorWaitWrite sock "Network.Socket.sendTo" $
            c_sendto s ptr (fromIntegral $ nbytes) 0{-flags-}
                            p_addr (fromIntegral sz)

    -- | Receive data from the socket. The socket need not be in a
    -- connected state. Returns @(bytes, nbytes, address)@ where @bytes@
    -- is a @String@ of length @nbytes@ representing the data received and
    -- @address@ is a 'SockAddr' representing the address of the sending
    -- socket.
    --
    -- NOTE: blocking on Windows unless you compile with -threaded (see
    -- GHC ticket #1129)
    {-# WARNING recvFrom "Use recvFrom defined in \"Network.Socket.ByteString\"" #-}
    recvFrom :: Socket -> Int -> IO (String, Int, SockAddr)
    recvFrom sock nbytes =
      allocaBytes nbytes $ \ptr -> do
        (len, sockaddr) <- recvBufFrom sock ptr nbytes
        str <- peekCStringLen (ptr, len)
        return (str, len, sockaddr)

    -- | Receive data from the socket, writing it into buffer instead of
    -- creating a new string.  The socket need not be in a connected
    -- state. Returns @(nbytes, address)@ where @nbytes@ is the number of
    -- bytes received and @address@ is a 'SockAddr' representing the
    -- address of the sending socket.
    --
    -- NOTE: blocking on Windows unless you compile with -threaded (see
    -- GHC ticket #1129)
    recvBufFrom :: Socket -> Ptr a -> Int -> IO (Int, SockAddr)
    recvBufFrom sock@(MkSocket s family _stype _protocol _status) ptr nbytes
     | nbytes <= 0 = ioError (mkInvalidRecvArgError "Network.Socket.recvFrom")
     | otherwise   =
        withNewSockAddr family $ \ptr_addr sz -> do
          alloca $ \ptr_len -> do
            poke ptr_len (fromIntegral sz)
            len <- throwSocketErrorWaitRead sock "Network.Socket.recvFrom" $
                       c_recvfrom s ptr (fromIntegral nbytes) 0{-flags-}
                                    ptr_addr ptr_len
            let len' = fromIntegral len
            if len' == 0
             then ioError (mkEOFError "Network.Socket.recvFrom")
             else do
               flg <- isConnected sock
                 -- For at least one implementation (WinSock 2), recvfrom() ignores
                 -- filling in the sockaddr for connected TCP sockets. Cope with
                 -- this by using getPeerName instead.
               sockaddr <-
                    if flg then
                       getPeerName sock
                    else
                       peekSockAddr ptr_addr
               return (len', sockaddr)

    -----------------------------------------------------------------------------
    -- send & recv

    -- | Send data to the socket. The socket must be connected to a remote
    -- socket. Returns the number of bytes sent.  Applications are
    -- responsible for ensuring that all data has been sent.
    --
    -- Sending data to closed socket may lead to undefined behaviour.
    {-# WARNING send "Use send defined in \"Network.Socket.ByteString\"" #-}
    send :: Socket  -- Bound/Connected Socket
         -> String  -- Data to send
         -> IO Int  -- Number of Bytes sent
    send sock xs = withCStringLen xs $ \(str, len) ->
        sendBuf sock (castPtr str) len

    -- | Send data to the socket. The socket must be connected to a remote
    -- socket. Returns the number of bytes sent.  Applications are
    -- responsible for ensuring that all data has been sent.
    --
    -- Sending data to closed socket may lead to undefined behaviour.
    sendBuf :: Socket     -- Bound/Connected Socket
            -> Ptr Word8  -- Pointer to the data to send
            -> Int        -- Length of the buffer
            -> IO Int     -- Number of Bytes sent
    sendBuf sock@(MkSocket s _family _stype _protocol _status) str len = do
       liftM fromIntegral $

    {-# LINE 695 "Network/Socket.hsc" #-}
         throwSocketErrorWaitWrite sock "Network.Socket.sendBuf" $
            c_send s str (fromIntegral len) 0{-flags-}

    {-# LINE 698 "Network/Socket.hsc" #-}

    -- | Receive data from the socket.  The socket must be in a connected
    -- state. This function may return fewer bytes than specified.  If the
    -- message is longer than the specified length, it may be discarded
    -- depending on the type of socket.  This function may block until a
    -- message arrives.
    --
    -- Considering hardware and network realities, the maximum number of
    -- bytes to receive should be a small power of 2, e.g., 4096.
    --
    -- For TCP sockets, a zero length return value means the peer has
    -- closed its half side of the connection.
    --
    -- Receiving data from closed socket may lead to undefined behaviour.
    {-# WARNING recv "Use recv defined in \"Network.Socket.ByteString\"" #-}
    recv :: Socket -> Int -> IO String
    recv sock l = fst <$> recvLen sock l

    {-# WARNING recvLen "Use recvLen defined in \"Network.Socket.ByteString\"" #-}
    recvLen :: Socket -> Int -> IO (String, Int)
    recvLen sock nbytes =
         allocaBytes nbytes $ \ptr -> do
            len <- recvBuf sock ptr nbytes
            s <- peekCStringLen (castPtr ptr,len)
            return (s, len)

    -- | Receive data from the socket.  The socket must be in a connected
    -- state. This function may return fewer bytes than specified.  If the
    -- message is longer than the specified length, it may be discarded
    -- depending on the type of socket.  This function may block until a
    -- message arrives.
    --
    -- Considering hardware and network realities, the maximum number of
    -- bytes to receive should be a small power of 2, e.g., 4096.
    --
    -- For TCP sockets, a zero length return value means the peer has
    -- closed its half side of the connection.
    --
    -- Receiving data from closed socket may lead to undefined behaviour.
    recvBuf :: Socket -> Ptr Word8 -> Int -> IO Int
    recvBuf sock@(MkSocket s _family _stype _protocol _status) ptr nbytes
     | nbytes <= 0 = ioError (mkInvalidRecvArgError "Network.Socket.recvBuf")
     | otherwise   = do
            len <-

    {-# LINE 749 "Network/Socket.hsc" #-}
                   throwSocketErrorWaitRead sock "Network.Socket.recvBuf" $
                       c_recv s (castPtr ptr) (fromIntegral nbytes) 0{-flags-}

    {-# LINE 752 "Network/Socket.hsc" #-}
            let len' = fromIntegral len
            if len' == 0
             then ioError (mkEOFError "Network.Socket.recvBuf")
             else return len'

    -- ---------------------------------------------------------------------------
    -- socketPort
    --
    -- The port number the given socket is currently connected to can be
    -- determined by calling $port$, is generally only useful when bind
    -- was given $aNY\_PORT$.

    socketPort :: Socket            -- Connected & Bound Socket
               -> IO PortNumber     -- Port Number of Socket
    socketPort sock@(MkSocket _ AF_INET _ _ _) = do
        (SockAddrInet port _) <- getSocketName sock
        return port

    {-# LINE 771 "Network/Socket.hsc" #-}
    socketPort sock@(MkSocket _ AF_INET6 _ _ _) = do
        (SockAddrInet6 port _ _ _) <- getSocketName sock
        return port

    {-# LINE 775 "Network/Socket.hsc" #-}
    socketPort (MkSocket _ family _ _ _) =
        ioError $ userError $
          "Network.Socket.socketPort: address family '" ++ show family ++
          "' not supported."

    -- ---------------------------------------------------------------------------
    -- getPeerName

    -- Calling $getPeerName$ returns the address details of the machine,
    -- other than the local one, which is connected to the socket. This is
    -- used in programs such as FTP to determine where to send the
    -- returning data.  The corresponding call to get the details of the
    -- local machine is $getSocketName$.

    getPeerName   :: Socket -> IO SockAddr
    getPeerName (MkSocket s family _ _ _) = do
     withNewSockAddr family $ \ptr sz -> do
       with (fromIntegral sz) $ \int_star -> do
       throwSocketErrorIfMinus1Retry_ "Network.Socket.getPeerName" $
         c_getpeername s ptr int_star
       _sz <- peek int_star
       peekSockAddr ptr

    getSocketName :: Socket -> IO SockAddr
    getSocketName (MkSocket s family _ _ _) = do
     withNewSockAddr family $ \ptr sz -> do
       with (fromIntegral sz) $ \int_star -> do
       throwSocketErrorIfMinus1Retry_ "Network.Socket.getSocketName" $
         c_getsockname s ptr int_star
       peekSockAddr ptr

    -----------------------------------------------------------------------------
    -- Socket Properties

    -- | Socket options for use with 'setSocketOption' and 'getSocketOption'.
    --
    -- The existence of a constructor does not imply that the relevant option
    -- is supported on your system: see 'isSupportedSocketOption'
    data SocketOption
        = Debug         -- ^ SO_DEBUG
        | ReuseAddr     -- ^ SO_REUSEADDR
        | Type          -- ^ SO_TYPE
        | SoError       -- ^ SO_ERROR
        | DontRoute     -- ^ SO_DONTROUTE
        | Broadcast     -- ^ SO_BROADCAST
        | SendBuffer    -- ^ SO_SNDBUF
        | RecvBuffer    -- ^ SO_RCVBUF
        | KeepAlive     -- ^ SO_KEEPALIVE
        | OOBInline     -- ^ SO_OOBINLINE
        | TimeToLive    -- ^ IP_TTL
        | MaxSegment    -- ^ TCP_MAXSEG
        | NoDelay       -- ^ TCP_NODELAY
        | Cork          -- ^ TCP_CORK
        | Linger        -- ^ SO_LINGER
        | ReusePort     -- ^ SO_REUSEPORT
        | RecvLowWater  -- ^ SO_RCVLOWAT
        | SendLowWater  -- ^ SO_SNDLOWAT
        | RecvTimeOut   -- ^ SO_RCVTIMEO
        | SendTimeOut   -- ^ SO_SNDTIMEO
        | UseLoopBack   -- ^ SO_USELOOPBACK
        | UserTimeout   -- ^ TCP_USER_TIMEOUT
        | IPv6Only      -- ^ IPV6_V6ONLY
        | CustomSockOpt (CInt, CInt)
        deriving (Show, Typeable)

    -- | Does the 'SocketOption' exist on this system?
    isSupportedSocketOption :: SocketOption -> Bool
    isSupportedSocketOption = isJust . packSocketOption

    -- | For a socket option, return Just (level, value) where level is the
    -- corresponding C option level constant (e.g. SOL_SOCKET) and value is
    -- the option constant itself (e.g. SO_DEBUG)
    -- If either constant does not exist, return Nothing.
    packSocketOption :: SocketOption -> Maybe (CInt, CInt)
    packSocketOption so =
      -- The Just here is a hack to disable GHC's overlapping pattern detection:
      -- the problem is if all constants are present, the fallback pattern is
      -- redundant, but if they aren't then it isn't. Hence we introduce an
      -- extra pattern (Nothing) that can't possibly happen, so that the
      -- fallback is always (in principle) necessary.
      -- I feel a little bad for including this, but such are the sacrifices we
      -- make while working with CPP - excluding the fallback pattern correctly
      -- would be a serious nuisance.
      -- (NB: comments elsewhere in this file refer to this one)
      case Just so of

    {-# LINE 862 "Network/Socket.hsc" #-}

    {-# LINE 863 "Network/Socket.hsc" #-}
        Just Debug         -> Just ((1), (1))
    {-# LINE 864 "Network/Socket.hsc" #-}

    {-# LINE 865 "Network/Socket.hsc" #-}

    {-# LINE 866 "Network/Socket.hsc" #-}
        Just ReuseAddr     -> Just ((1), (2))
    {-# LINE 867 "Network/Socket.hsc" #-}

    {-# LINE 868 "Network/Socket.hsc" #-}

    {-# LINE 869 "Network/Socket.hsc" #-}
        Just Type          -> Just ((1), (3))
    {-# LINE 870 "Network/Socket.hsc" #-}

    {-# LINE 871 "Network/Socket.hsc" #-}

    {-# LINE 872 "Network/Socket.hsc" #-}
        Just SoError       -> Just ((1), (4))
    {-# LINE 873 "Network/Socket.hsc" #-}

    {-# LINE 874 "Network/Socket.hsc" #-}

    {-# LINE 875 "Network/Socket.hsc" #-}
        Just DontRoute     -> Just ((1), (5))
    {-# LINE 876 "Network/Socket.hsc" #-}

    {-# LINE 877 "Network/Socket.hsc" #-}

    {-# LINE 878 "Network/Socket.hsc" #-}
        Just Broadcast     -> Just ((1), (6))
    {-# LINE 879 "Network/Socket.hsc" #-}

    {-# LINE 880 "Network/Socket.hsc" #-}

    {-# LINE 881 "Network/Socket.hsc" #-}
        Just SendBuffer    -> Just ((1), (7))
    {-# LINE 882 "Network/Socket.hsc" #-}

    {-# LINE 883 "Network/Socket.hsc" #-}

    {-# LINE 884 "Network/Socket.hsc" #-}
        Just RecvBuffer    -> Just ((1), (8))
    {-# LINE 885 "Network/Socket.hsc" #-}

    {-# LINE 886 "Network/Socket.hsc" #-}

    {-# LINE 887 "Network/Socket.hsc" #-}
        Just KeepAlive     -> Just ((1), (9))
    {-# LINE 888 "Network/Socket.hsc" #-}

    {-# LINE 889 "Network/Socket.hsc" #-}

    {-# LINE 890 "Network/Socket.hsc" #-}
        Just OOBInline     -> Just ((1), (10))
    {-# LINE 891 "Network/Socket.hsc" #-}

    {-# LINE 892 "Network/Socket.hsc" #-}

    {-# LINE 893 "Network/Socket.hsc" #-}
        Just Linger        -> Just ((1), (13))
    {-# LINE 894 "Network/Socket.hsc" #-}

    {-# LINE 895 "Network/Socket.hsc" #-}

    {-# LINE 896 "Network/Socket.hsc" #-}
        Just ReusePort     -> Just ((1), (15))
    {-# LINE 897 "Network/Socket.hsc" #-}

    {-# LINE 898 "Network/Socket.hsc" #-}

    {-# LINE 899 "Network/Socket.hsc" #-}
        Just RecvLowWater  -> Just ((1), (18))
    {-# LINE 900 "Network/Socket.hsc" #-}

    {-# LINE 901 "Network/Socket.hsc" #-}

    {-# LINE 902 "Network/Socket.hsc" #-}
        Just SendLowWater  -> Just ((1), (19))
    {-# LINE 903 "Network/Socket.hsc" #-}

    {-# LINE 904 "Network/Socket.hsc" #-}

    {-# LINE 905 "Network/Socket.hsc" #-}
        Just RecvTimeOut   -> Just ((1), (20))
    {-# LINE 906 "Network/Socket.hsc" #-}

    {-# LINE 907 "Network/Socket.hsc" #-}

    {-# LINE 908 "Network/Socket.hsc" #-}
        Just SendTimeOut   -> Just ((1), (21))
    {-# LINE 909 "Network/Socket.hsc" #-}

    {-# LINE 910 "Network/Socket.hsc" #-}

    {-# LINE 913 "Network/Socket.hsc" #-}

    {-# LINE 914 "Network/Socket.hsc" #-}

    {-# LINE 915 "Network/Socket.hsc" #-}

    {-# LINE 916 "Network/Socket.hsc" #-}
        Just TimeToLive    -> Just ((0), (2))
    {-# LINE 917 "Network/Socket.hsc" #-}

    {-# LINE 918 "Network/Socket.hsc" #-}

    {-# LINE 919 "Network/Socket.hsc" #-}

    {-# LINE 920 "Network/Socket.hsc" #-}

    {-# LINE 921 "Network/Socket.hsc" #-}
        Just MaxSegment    -> Just ((6), (2))
    {-# LINE 922 "Network/Socket.hsc" #-}

    {-# LINE 923 "Network/Socket.hsc" #-}

    {-# LINE 924 "Network/Socket.hsc" #-}
        Just NoDelay       -> Just ((6), (1))
    {-# LINE 925 "Network/Socket.hsc" #-}

    {-# LINE 926 "Network/Socket.hsc" #-}

    {-# LINE 927 "Network/Socket.hsc" #-}
        Just UserTimeout   -> Just ((6), (18))
    {-# LINE 928 "Network/Socket.hsc" #-}

    {-# LINE 929 "Network/Socket.hsc" #-}

    {-# LINE 930 "Network/Socket.hsc" #-}
        Just Cork          -> Just ((6), (3))
    {-# LINE 931 "Network/Socket.hsc" #-}

    {-# LINE 932 "Network/Socket.hsc" #-}

    {-# LINE 933 "Network/Socket.hsc" #-}

    {-# LINE 934 "Network/Socket.hsc" #-}

    {-# LINE 935 "Network/Socket.hsc" #-}
        Just IPv6Only      -> Just ((41), (26))
    {-# LINE 936 "Network/Socket.hsc" #-}

    {-# LINE 937 "Network/Socket.hsc" #-}

    {-# LINE 938 "Network/Socket.hsc" #-}
        Just (CustomSockOpt opt) -> Just opt
        _             -> Nothing

    -- | Return the option level and option value if they exist,
    -- otherwise throw an error that begins "Network.Socket." ++ the String
    -- parameter
    packSocketOption' :: String -> SocketOption -> IO (CInt, CInt)
    packSocketOption' caller so = maybe err return (packSocketOption so)
     where
      err = ioError . userError . concat $ ["Network.Socket.", caller,
        ": socket option ", show so, " unsupported on this system"]

    -- | Set a socket option that expects an Int value.
    -- There is currently no API to set e.g. the timeval socket options
    setSocketOption :: Socket
                    -> SocketOption -- Option Name
                    -> Int          -- Option Value
                    -> IO ()
    setSocketOption (MkSocket s _ _ _ _) so v = do
       (level, opt) <- packSocketOption' "setSocketOption" so
       with (fromIntegral v) $ \ptr_v -> do
       throwSocketErrorIfMinus1_ "Network.Socket.setSocketOption" $
           c_setsockopt s level opt ptr_v
              (fromIntegral (sizeOf (undefined :: CInt)))
       return ()

    -- | Get a socket option that gives an Int value.
    -- There is currently no API to get e.g. the timeval socket options
    getSocketOption :: Socket
                    -> SocketOption  -- Option Name
                    -> IO Int        -- Option Value
    getSocketOption (MkSocket s _ _ _ _) so = do
       (level, opt) <- packSocketOption' "getSocketOption" so
       alloca $ \ptr_v ->
         with (fromIntegral (sizeOf (undefined :: CInt))) $ \ptr_sz -> do
           throwSocketErrorIfMinus1Retry_ "Network.Socket.getSocketOption" $
             c_getsockopt s level opt ptr_v ptr_sz
           fromIntegral `liftM` peek ptr_v

    {-# LINE 980 "Network/Socket.hsc" #-}
    -- | Returns the processID, userID and groupID of the socket's peer.
    --
    -- Only available on platforms that support SO_PEERCRED or GETPEEREID(3)
    -- on domain sockets.
    -- GETPEEREID(3) returns userID and groupID. processID is always 0.
    getPeerCred :: Socket -> IO (CUInt, CUInt, CUInt)
    getPeerCred sock = do

    {-# LINE 988 "Network/Socket.hsc" #-}
      let fd = fdSocket sock
      let sz = (12)
    {-# LINE 990 "Network/Socket.hsc" #-}
      allocaBytes sz $ \ ptr_cr ->
       with (fromIntegral sz) $ \ ptr_sz -> do
         _ <- ($) throwSocketErrorIfMinus1Retry "Network.Socket.getPeerCred" $
           c_getsockopt fd (1) (17) ptr_cr ptr_sz
    {-# LINE 994 "Network/Socket.hsc" #-}
         pid <- ((\hsc_ptr -> peekByteOff hsc_ptr 0)) ptr_cr
    {-# LINE 995 "Network/Socket.hsc" #-}
         uid <- ((\hsc_ptr -> peekByteOff hsc_ptr 4)) ptr_cr
    {-# LINE 996 "Network/Socket.hsc" #-}
         gid <- ((\hsc_ptr -> peekByteOff hsc_ptr 8)) ptr_cr
    {-# LINE 997 "Network/Socket.hsc" #-}
         return (pid, uid, gid)

    {-# LINE 1002 "Network/Socket.hsc" #-}

    {-# LINE 1017 "Network/Socket.hsc" #-}

    {-# LINE 1018 "Network/Socket.hsc" #-}

    #if !(MIN_VERSION_base(4,3,1))
    closeFdWith closer fd = closer fd
    #endif

    {-# LINE 1024 "Network/Socket.hsc" #-}
    -- sending/receiving ancillary socket data; low-level mechanism
    -- for transmitting file descriptors, mainly.
    sendFd :: Socket -> CInt -> IO ()
    sendFd sock outfd = do
      _ <- ($) throwSocketErrorWaitWrite sock "Network.Socket.sendFd" $
         c_sendFd (fdSocket sock) outfd
       -- Note: If Winsock supported FD-passing, thi would have been
       -- incorrect (since socket FDs need to be closed via closesocket().)
      closeFd outfd

    -- | Receive a file descriptor over a domain socket. Note that the resulting
    -- file descriptor may have to be put into non-blocking mode in order to be
    -- used safely. See 'setNonBlockIfNeeded'.
    recvFd :: Socket -> IO CInt
    recvFd sock = do
      theFd <- throwSocketErrorWaitRead sock "Network.Socket.recvFd" $
                   c_recvFd (fdSocket sock)
      return theFd

    foreign import ccall SAFE_ON_WIN "sendFd" c_sendFd :: CInt -> CInt -> IO CInt
    foreign import ccall SAFE_ON_WIN "recvFd" c_recvFd :: CInt -> IO CInt

    {-# LINE 1047 "Network/Socket.hsc" #-}

    -- ---------------------------------------------------------------------------
    -- Utility Functions

    aNY_PORT :: PortNumber
    aNY_PORT = 0

    -- | The IPv4 wild card address.

    iNADDR_ANY :: HostAddress
    iNADDR_ANY = htonl (0)
    {-# LINE 1058 "Network/Socket.hsc" #-}

    -- | Converts the from host byte order to network byte order.
    foreign import CALLCONV unsafe "htonl" htonl :: Word32 -> Word32
    -- | Converts the from network byte order to host byte order.
    foreign import CALLCONV unsafe "ntohl" ntohl :: Word32 -> Word32

    {-# LINE 1065 "Network/Socket.hsc" #-}
    -- | The IPv6 wild card address.

    iN6ADDR_ANY :: HostAddress6
    iN6ADDR_ANY = (0, 0, 0, 0)

    {-# LINE 1070 "Network/Socket.hsc" #-}

    sOMAXCONN :: Int
    sOMAXCONN = 128
    {-# LINE 1073 "Network/Socket.hsc" #-}

    sOL_SOCKET :: Int
    sOL_SOCKET = 1
    {-# LINE 1076 "Network/Socket.hsc" #-}

    {-# LINE 1078 "Network/Socket.hsc" #-}
    sCM_RIGHTS :: Int
    sCM_RIGHTS = 1
    {-# LINE 1080 "Network/Socket.hsc" #-}

    {-# LINE 1081 "Network/Socket.hsc" #-}

    -- | This is the value of SOMAXCONN, typically 128.
    -- 128 is good enough for normal network servers but
    -- is too small for high performance servers.
    maxListenQueue :: Int
    maxListenQueue = sOMAXCONN

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

    data ShutdownCmd
     = ShutdownReceive
     | ShutdownSend
     | ShutdownBoth
     deriving Typeable

    sdownCmdToInt :: ShutdownCmd -> CInt
    sdownCmdToInt ShutdownReceive = 0
    sdownCmdToInt ShutdownSend    = 1
    sdownCmdToInt ShutdownBoth    = 2

    -- | Shut down one or both halves of the connection, depending on the
    -- second argument to the function.  If the second argument is
    -- 'ShutdownReceive', further receives are disallowed.  If it is
    -- 'ShutdownSend', further sends are disallowed.  If it is
    -- 'ShutdownBoth', further sends and receives are disallowed.
    shutdown :: Socket -> ShutdownCmd -> IO ()
    shutdown (MkSocket s _ _ _ _) stype = do
      throwSocketErrorIfMinus1Retry_ "Network.Socket.shutdown" $
        c_shutdown s (sdownCmdToInt stype)
      return ()

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

    -- | Close the socket. Sending data to or receiving data from closed socket
    -- may lead to undefined behaviour.
    close :: Socket -> IO ()
    close (MkSocket s _ _ _ socketStatus) = do
     modifyMVar_ socketStatus $ \ status ->
       case status of
         ConvertedToHandle ->
             ioError (userError ("close: converted to a Handle, use hClose instead"))
         Closed ->
             return status
         _ -> closeFdWith (closeFd . fromIntegral) (fromIntegral s) >> return Closed

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

    -- | Determines whether 'close' has been used on the 'Socket'. This
    -- does /not/ indicate any status about the socket beyond this. If the
    -- socket has been closed remotely, this function can still return
    -- 'True'.
    isConnected :: Socket -> IO Bool
    isConnected (MkSocket _ _ _ _ status) = do
        value <- readMVar status
        return (value == Connected)

    -- -----------------------------------------------------------------------------
    -- Socket Predicates

    isBound :: Socket -> IO Bool
    isBound (MkSocket _ _ _ _ status) = do
        value <- readMVar status
        return (value == Bound)

    isListening :: Socket -> IO Bool
    isListening (MkSocket _ _ _  _ status) = do
        value <- readMVar status
        return (value == Listening)

    isReadable  :: Socket -> IO Bool
    isReadable (MkSocket _ _ _ _ status) = do
        value <- readMVar status
        return (value == Listening || value == Connected)

    isWritable  :: Socket -> IO Bool
    isWritable = isReadable -- sort of.

    isAcceptable :: Socket -> IO Bool

    {-# LINE 1160 "Network/Socket.hsc" #-}
    isAcceptable (MkSocket _ AF_UNIX x _ status)
        | x == Stream || x == SeqPacket = do
            value <- readMVar status
            return (value == Connected || value == Bound || value == Listening)
    isAcceptable (MkSocket _ AF_UNIX _ _ _) = return False

    {-# LINE 1166 "Network/Socket.hsc" #-}
    isAcceptable (MkSocket _ _ _ _ status) = do
        value <- readMVar status
        return (value == Connected || value == Listening)

    -- -----------------------------------------------------------------------------
    -- Internet address manipulation routines:

    inet_addr :: String -> IO HostAddress
    inet_addr ipstr = withSocketsDo $ do
       withCString ipstr $ \str -> do
       had <- c_inet_addr str
       if had == -1
        then ioError $ userError $
          "Network.Socket.inet_addr: Malformed address: " ++ ipstr
        else return had  -- network byte order

    inet_ntoa :: HostAddress -> IO String
    inet_ntoa haddr = withSocketsDo $ do
      pstr <- c_inet_ntoa haddr
      peekCString pstr

    -- | Turns a Socket into an 'Handle'. By default, the new handle is
    -- unbuffered. Use 'System.IO.hSetBuffering' to change the buffering.
    --
    -- Note that since a 'Handle' is automatically closed by a finalizer
    -- when it is no longer referenced, you should avoid doing any more
    -- operations on the 'Socket' after calling 'socketToHandle'.  To
    -- close the 'Socket' after 'socketToHandle', call 'System.IO.hClose'
    -- on the 'Handle'.

    socketToHandle :: Socket -> IOMode -> IO Handle
    socketToHandle s@(MkSocket fd _ _ _ socketStatus) mode = do
     modifyMVar socketStatus $ \ status ->
        if status == ConvertedToHandle
            then ioError (userError ("socketToHandle: already a Handle"))
            else do
        h <- fdToHandle' (fromIntegral fd) (Just GHC.IO.Device.Stream) True (show s) mode True{-bin-}
        hSetBuffering h NoBuffering
        return (ConvertedToHandle, h)

    -- | Pack a list of values into a bitmask.  The possible mappings from
    -- value to bit-to-set are given as the first argument.  We assume
    -- that each value can cause exactly one bit to be set; unpackBits will
    -- break if this property is not true.

    packBits :: (Eq a, Num b, Bits b) => [(a, b)] -> [a] -> b

    packBits mapping xs = foldl' pack 0 mapping
        where pack acc (k, v) | k `elem` xs = acc .|. v
                              | otherwise   = acc

    -- | Unpack a bitmask into a list of values.

    unpackBits :: (Num b, Bits b) => [(a, b)] -> b -> [a]

    -- Be permissive and ignore unknown bit values. At least on OS X,
    -- getaddrinfo returns an ai_flags field with bits set that have no
    -- entry in <netdb.h>.
    unpackBits [] _    = []
    unpackBits ((k,v):xs) r
        | r .&. v /= 0 = k : unpackBits xs (r .&. complement v)
        | otherwise    = unpackBits xs r

    -----------------------------------------------------------------------------
    -- Address and service lookups

    {-# LINE 1233 "Network/Socket.hsc" #-}

    -- | Flags that control the querying behaviour of 'getAddrInfo'.
    --   For more information, see <https://tools.ietf.org/html/rfc3493#page-25>
    data AddrInfoFlag =
        -- | The list of returned 'AddrInfo' values will
        --   only contain IPv4 addresses if the local system has at least
        --   one IPv4 interface configured, and likewise for IPv6.
        --   (Only some platforms support this.)
          AI_ADDRCONFIG
        -- | If 'AI_ALL' is specified, return all matching IPv6 and
        --   IPv4 addresses.  Otherwise, this flag has no effect.
        --   (Only some platforms support this.)
        | AI_ALL
        -- | The 'addrCanonName' field of the first returned
        --   'AddrInfo' will contain the "canonical name" of the host.
        | AI_CANONNAME
        -- | The 'HostName' argument /must/ be a numeric
        --   address in string form, and network name lookups will not be
        --   attempted.
        | AI_NUMERICHOST
        -- | The 'ServiceName' argument /must/ be a port
        --   number in string form, and service name lookups will not be
        --   attempted. (Only some platforms support this.)
        | AI_NUMERICSERV
        -- | If no 'HostName' value is provided, the network
        --   address in each 'SockAddr'
        --   will be left as a "wild card", i.e. as either 'iNADDR_ANY'
        --   or 'iN6ADDR_ANY'.  This is useful for server applications that
        --   will accept connections from any client.
        | AI_PASSIVE
        -- | If an IPv6 lookup is performed, and no IPv6
        --   addresses are found, IPv6-mapped IPv4 addresses will be
        --   returned. (Only some platforms support this.)
        | AI_V4MAPPED
        deriving (Eq, Read, Show, Typeable)

    aiFlagMapping :: [(AddrInfoFlag, CInt)]

    aiFlagMapping =
        [

    {-# LINE 1274 "Network/Socket.hsc" #-}
         (AI_ADDRCONFIG, 32),
    {-# LINE 1275 "Network/Socket.hsc" #-}

    {-# LINE 1278 "Network/Socket.hsc" #-}

    {-# LINE 1279 "Network/Socket.hsc" #-}
         (AI_ALL, 16),
    {-# LINE 1280 "Network/Socket.hsc" #-}

    {-# LINE 1283 "Network/Socket.hsc" #-}
         (AI_CANONNAME, 2),
    {-# LINE 1284 "Network/Socket.hsc" #-}
         (AI_NUMERICHOST, 4),
    {-# LINE 1285 "Network/Socket.hsc" #-}

    {-# LINE 1286 "Network/Socket.hsc" #-}
         (AI_NUMERICSERV, 1024),
    {-# LINE 1287 "Network/Socket.hsc" #-}

    {-# LINE 1290 "Network/Socket.hsc" #-}
         (AI_PASSIVE, 1),
    {-# LINE 1291 "Network/Socket.hsc" #-}

    {-# LINE 1292 "Network/Socket.hsc" #-}
         (AI_V4MAPPED, 8)
    {-# LINE 1293 "Network/Socket.hsc" #-}

    {-# LINE 1296 "Network/Socket.hsc" #-}
        ]

    -- | Indicate whether the given 'AddrInfoFlag' will have any effect on
    -- this system.
    addrInfoFlagImplemented :: AddrInfoFlag -> Bool
    addrInfoFlagImplemented f = packBits aiFlagMapping [f] /= 0

    data AddrInfo =
        AddrInfo {
            addrFlags :: [AddrInfoFlag],
            addrFamily :: Family,
            addrSocketType :: SocketType,
            addrProtocol :: ProtocolNumber,
            addrAddress :: SockAddr,
            addrCanonName :: Maybe String
            }
        deriving (Eq, Show, Typeable)

    instance Storable AddrInfo where
        sizeOf    _ = 48
    {-# LINE 1316 "Network/Socket.hsc" #-}
        alignment _ = alignment (undefined :: CInt)

        peek p = do
            ai_flags <- ((\hsc_ptr -> peekByteOff hsc_ptr 0)) p
    {-# LINE 1320 "Network/Socket.hsc" #-}
            ai_family <- ((\hsc_ptr -> peekByteOff hsc_ptr 4)) p
    {-# LINE 1321 "Network/Socket.hsc" #-}
            ai_socktype <- ((\hsc_ptr -> peekByteOff hsc_ptr 8)) p
    {-# LINE 1322 "Network/Socket.hsc" #-}
            ai_protocol <- ((\hsc_ptr -> peekByteOff hsc_ptr 12)) p
    {-# LINE 1323 "Network/Socket.hsc" #-}
            ai_addr <- ((\hsc_ptr -> peekByteOff hsc_ptr 24)) p >>= peekSockAddr
    {-# LINE 1324 "Network/Socket.hsc" #-}
            ai_canonname_ptr <- ((\hsc_ptr -> peekByteOff hsc_ptr 32)) p
    {-# LINE 1325 "Network/Socket.hsc" #-}

            ai_canonname <- if ai_canonname_ptr == nullPtr
                            then return Nothing
                            else liftM Just $ peekCString ai_canonname_ptr

            socktype <- unpackSocketType' "AddrInfo.peek" ai_socktype
            return (AddrInfo
                    {
                     addrFlags = unpackBits aiFlagMapping ai_flags,
                     addrFamily = unpackFamily ai_family,
                     addrSocketType = socktype,
                     addrProtocol = ai_protocol,
                     addrAddress = ai_addr,
                     addrCanonName = ai_canonname
                    })

        poke p (AddrInfo flags family socketType protocol _ _) = do
            c_stype <- packSocketTypeOrThrow "AddrInfo.poke" socketType

            ((\hsc_ptr -> pokeByteOff hsc_ptr 0)) p (packBits aiFlagMapping flags)
    {-# LINE 1345 "Network/Socket.hsc" #-}
            ((\hsc_ptr -> pokeByteOff hsc_ptr 4)) p (packFamily family)
    {-# LINE 1346 "Network/Socket.hsc" #-}
            ((\hsc_ptr -> pokeByteOff hsc_ptr 8)) p c_stype
    {-# LINE 1347 "Network/Socket.hsc" #-}
            ((\hsc_ptr -> pokeByteOff hsc_ptr 12)) p protocol
    {-# LINE 1348 "Network/Socket.hsc" #-}

            -- stuff below is probably not needed, but let's zero it for safety

            ((\hsc_ptr -> pokeByteOff hsc_ptr 16)) p (0::CSize)
    {-# LINE 1352 "Network/Socket.hsc" #-}
            ((\hsc_ptr -> pokeByteOff hsc_ptr 24)) p nullPtr
    {-# LINE 1353 "Network/Socket.hsc" #-}
            ((\hsc_ptr -> pokeByteOff hsc_ptr 32)) p nullPtr
    {-# LINE 1354 "Network/Socket.hsc" #-}
            ((\hsc_ptr -> pokeByteOff hsc_ptr 40)) p nullPtr
    {-# LINE 1355 "Network/Socket.hsc" #-}

    -- | Flags that control the querying behaviour of 'getNameInfo'.
    --   For more information, see <https://tools.ietf.org/html/rfc3493#page-30>
    data NameInfoFlag =
        -- | Resolve a datagram-based service name.  This is
        --   required only for the few protocols that have different port
        --   numbers for their datagram-based versions than for their
        --   stream-based versions.
          NI_DGRAM
        -- | If the hostname cannot be looked up, an IO error is thrown.
        | NI_NAMEREQD
        -- | If a host is local, return only the hostname part of the FQDN.
        | NI_NOFQDN
        -- | The name of the host is not looked up.
        --   Instead, a numeric representation of the host's
        --   address is returned.  For an IPv4 address, this will be a
        --   dotted-quad string.  For IPv6, it will be colon-separated
        --   hexadecimal.
        | NI_NUMERICHOST
        -- | The name of the service is not
        --   looked up.  Instead, a numeric representation of the
        --   service is returned.
        | NI_NUMERICSERV
        deriving (Eq, Read, Show, Typeable)

    niFlagMapping :: [(NameInfoFlag, CInt)]

    niFlagMapping = [(NI_DGRAM, 16),
    {-# LINE 1383 "Network/Socket.hsc" #-}
                     (NI_NAMEREQD, 8),
    {-# LINE 1384 "Network/Socket.hsc" #-}
                     (NI_NOFQDN, 4),
    {-# LINE 1385 "Network/Socket.hsc" #-}
                     (NI_NUMERICHOST, 1),
    {-# LINE 1386 "Network/Socket.hsc" #-}
                     (NI_NUMERICSERV, 2)]
    {-# LINE 1387 "Network/Socket.hsc" #-}

    -- | Default hints for address lookup with 'getAddrInfo'.  The values
    -- of the 'addrAddress' and 'addrCanonName' fields are 'undefined',
    -- and are never inspected by 'getAddrInfo'.
    --
    -- >>> addrFlags defaultHints
    -- []
    -- >>> addrFamily defaultHints
    -- AF_UNSPEC
    -- >>> addrSocketType defaultHints
    -- NoSocketType
    -- >>> addrProtocol defaultHints
    -- 0

    defaultHints :: AddrInfo
    defaultHints = AddrInfo {
                             addrFlags = [],
                             addrFamily = AF_UNSPEC,
                             addrSocketType = NoSocketType,
                             addrProtocol = defaultProtocol,
                             addrAddress = undefined,
                             addrCanonName = undefined
                            }

    -- | Resolve a host or service name to one or more addresses.
    -- The 'AddrInfo' values that this function returns contain 'SockAddr'
    -- values that you can pass directly to 'connect' or
    -- 'bind'.
    --
    -- This function is protocol independent.  It can return both IPv4 and
    -- IPv6 address information.
    --
    -- The 'AddrInfo' argument specifies the preferred query behaviour,
    -- socket options, or protocol.  You can override these conveniently
    -- using Haskell's record update syntax on 'defaultHints', for example
    -- as follows:
    --
    -- >>> let hints = defaultHints { addrFlags = [AI_NUMERICHOST], addrSocketType = Stream }
    --
    -- You must provide a 'Just' value for at least one of the 'HostName'
    -- or 'ServiceName' arguments.  'HostName' can be either a numeric
    -- network address (dotted quad for IPv4, colon-separated hex for
    -- IPv6) or a hostname.  In the latter case, its addresses will be
    -- looked up unless 'AI_NUMERICHOST' is specified as a hint.  If you
    -- do not provide a 'HostName' value /and/ do not set 'AI_PASSIVE' as
    -- a hint, network addresses in the result will contain the address of
    -- the loopback interface.
    --
    -- If the query fails, this function throws an IO exception instead of
    -- returning an empty list.  Otherwise, it returns a non-empty list
    -- of 'AddrInfo' values.
    --
    -- There are several reasons why a query might result in several
    -- values.  For example, the queried-for host could be multihomed, or
    -- the service might be available via several protocols.
    --
    -- Note: the order of arguments is slightly different to that defined
    -- for @getaddrinfo@ in RFC 2553.  The 'AddrInfo' parameter comes first
    -- to make partial application easier.
    --
    -- >>> addr:_ <- getAddrInfo (Just hints) (Just "127.0.0.1") (Just "http")
    -- >>> addrAddress addr
    -- 127.0.0.1:80

    getAddrInfo :: Maybe AddrInfo -- ^ preferred socket type or protocol
                -> Maybe HostName -- ^ host name to look up
                -> Maybe ServiceName -- ^ service name to look up
                -> IO [AddrInfo] -- ^ resolved addresses, with "best" first

    getAddrInfo hints node service = withSocketsDo $
      maybeWith withCString node $ \c_node ->
        maybeWith withCString service $ \c_service ->
          maybeWith with filteredHints $ \c_hints ->
            alloca $ \ptr_ptr_addrs -> do
              ret <- c_getaddrinfo c_node c_service c_hints ptr_ptr_addrs
              case ret of
                0 -> do ptr_addrs <- peek ptr_ptr_addrs
                        ais <- followAddrInfo ptr_addrs
                        c_freeaddrinfo ptr_addrs
                        return ais
                _ -> do err <- gai_strerror ret
                        ioError (ioeSetErrorString
                                 (mkIOError NoSuchThing "Network.Socket.getAddrInfo" Nothing
                                  Nothing) err)
        -- Leaving out the service and using AI_NUMERICSERV causes a
        -- segfault on OS X 10.8.2. This code removes AI_NUMERICSERV
        -- (which has no effect) in that case.
      where

    {-# LINE 1480 "Network/Socket.hsc" #-}
        filteredHints = hints

    {-# LINE 1482 "Network/Socket.hsc" #-}

    followAddrInfo :: Ptr AddrInfo -> IO [AddrInfo]

    followAddrInfo ptr_ai | ptr_ai == nullPtr = return []
                          | otherwise = do
        a <- peek ptr_ai
        as <- ((\hsc_ptr -> peekByteOff hsc_ptr 40)) ptr_ai >>= followAddrInfo
    {-# LINE 1489 "Network/Socket.hsc" #-}
        return (a:as)

    foreign import ccall safe "hsnet_getaddrinfo"
        c_getaddrinfo :: CString -> CString -> Ptr AddrInfo -> Ptr (Ptr AddrInfo)
                      -> IO CInt

    foreign import ccall safe "hsnet_freeaddrinfo"
        c_freeaddrinfo :: Ptr AddrInfo -> IO ()

    gai_strerror :: CInt -> IO String

    {-# LINE 1501 "Network/Socket.hsc" #-}
    gai_strerror n = c_gai_strerror n >>= peekCString

    foreign import ccall safe "gai_strerror"
        c_gai_strerror :: CInt -> IO CString

    {-# LINE 1508 "Network/Socket.hsc" #-}

    withCStringIf :: Bool -> Int -> (CSize -> CString -> IO a) -> IO a
    withCStringIf False _ f = f 0 nullPtr
    withCStringIf True n f = allocaBytes n (f (fromIntegral n))

    -- | Resolve an address to a host or service name.
    -- This function is protocol independent.
    -- The list of 'NameInfoFlag' values controls query behaviour.
    --
    -- If a host or service's name cannot be looked up, then the numeric
    -- form of the address or service will be returned.
    --
    -- If the query fails, this function throws an IO exception.
    --
    -- Example:
    -- @
    --   (hostName, _) <- getNameInfo [] True False myAddress
    -- @

    getNameInfo :: [NameInfoFlag] -- ^ flags to control lookup behaviour
                -> Bool -- ^ whether to look up a hostname
                -> Bool -- ^ whether to look up a service name
                -> SockAddr -- ^ the address to look up
                -> IO (Maybe HostName, Maybe ServiceName)

    getNameInfo flags doHost doService addr = withSocketsDo $
      withCStringIf doHost (1025) $ \c_hostlen c_host ->
    {-# LINE 1535 "Network/Socket.hsc" #-}
        withCStringIf doService (32) $ \c_servlen c_serv -> do
    {-# LINE 1536 "Network/Socket.hsc" #-}
          withSockAddr addr $ \ptr_addr sz -> do
            ret <- c_getnameinfo ptr_addr (fromIntegral sz) c_host c_hostlen
                                 c_serv c_servlen (packBits niFlagMapping flags)
            case ret of
              0 -> do
                let peekIf doIf c_val = if doIf
                                         then liftM Just $ peekCString c_val
                                         else return Nothing
                host <- peekIf doHost c_host
                serv <- peekIf doService c_serv
                return (host, serv)
              _ -> do err <- gai_strerror ret
                      ioError (ioeSetErrorString
                               (mkIOError NoSuchThing "Network.Socket.getNameInfo" Nothing
                                Nothing) err)

    foreign import ccall safe "hsnet_getnameinfo"
        c_getnameinfo :: Ptr SockAddr -> CInt{-CSockLen???-} -> CString -> CSize -> CString
                      -> CSize -> CInt -> IO CInt

    {-# LINE 1556 "Network/Socket.hsc" #-}

    mkInvalidRecvArgError :: String -> IOError
    mkInvalidRecvArgError loc = ioeSetErrorString (mkIOError
                                        InvalidArgument
                                        loc Nothing Nothing) "non-positive length"

    mkEOFError :: String -> IOError
    mkEOFError loc = ioeSetErrorString (mkIOError EOF loc Nothing Nothing) "end of file"

    -- ---------------------------------------------------------------------------
    -- foreign imports from the C library

    foreign import ccall unsafe "hsnet_inet_ntoa"
      c_inet_ntoa :: HostAddress -> IO (Ptr CChar)

    foreign import CALLCONV unsafe "inet_addr"
      c_inet_addr :: Ptr CChar -> IO HostAddress

    foreign import CALLCONV unsafe "shutdown"
      c_shutdown :: CInt -> CInt -> IO CInt

    closeFd :: CInt -> IO ()
    closeFd fd = throwSocketErrorIfMinus1_ "Network.Socket.close" $ c_close fd

    {-# LINE 1581 "Network/Socket.hsc" #-}
    foreign import ccall unsafe "close"
      c_close :: CInt -> IO CInt

    {-# LINE 1587 "Network/Socket.hsc" #-}

    foreign import CALLCONV unsafe "socket"
      c_socket :: CInt -> CInt -> CInt -> IO CInt
    foreign import CALLCONV unsafe "bind"
      c_bind :: CInt -> Ptr SockAddr -> CInt{-CSockLen???-} -> IO CInt
    foreign import CALLCONV SAFE_ON_WIN "connect"
      c_connect :: CInt -> Ptr SockAddr -> CInt{-CSockLen???-} -> IO CInt

    {-# LINE 1595 "Network/Socket.hsc" #-}
    foreign import CALLCONV unsafe "accept4"
      c_accept4 :: CInt -> Ptr SockAddr -> Ptr CInt{-CSockLen???-} -> CInt -> IO CInt

    {-# LINE 1601 "Network/Socket.hsc" #-}
    foreign import CALLCONV unsafe "listen"
      c_listen :: CInt -> CInt -> IO CInt

    {-# LINE 1610 "Network/Socket.hsc" #-}

    foreign import CALLCONV unsafe "send"
      c_send :: CInt -> Ptr a -> CSize -> CInt -> IO CInt
    foreign import CALLCONV SAFE_ON_WIN "sendto"
      c_sendto :: CInt -> Ptr a -> CSize -> CInt -> Ptr SockAddr -> CInt -> IO CInt
    foreign import CALLCONV unsafe "recv"
      c_recv :: CInt -> Ptr CChar -> CSize -> CInt -> IO CInt
    foreign import CALLCONV SAFE_ON_WIN "recvfrom"
      c_recvfrom :: CInt -> Ptr a -> CSize -> CInt -> Ptr SockAddr -> Ptr CInt -> IO CInt
    foreign import CALLCONV unsafe "getpeername"
      c_getpeername :: CInt -> Ptr SockAddr -> Ptr CInt -> IO CInt
    foreign import CALLCONV unsafe "getsockname"
      c_getsockname :: CInt -> Ptr SockAddr -> Ptr CInt -> IO CInt

    foreign import CALLCONV unsafe "getsockopt"
      c_getsockopt :: CInt -> CInt -> CInt -> Ptr CInt -> Ptr CInt -> IO CInt
    foreign import CALLCONV unsafe "setsockopt"
      c_setsockopt :: CInt -> CInt -> CInt -> Ptr CInt -> CInt -> IO CInt

    {-# LINE 1633 "Network/Socket.hsc" #-}
    -- ---------------------------------------------------------------------------
    -- * Deprecated aliases

    -- $deprecated-aliases
    --
    -- These aliases are deprecated and should not be used in new code.
    -- They will be removed in some future version of the package.

    {-# DEPRECATED bindSocket "use 'bind'" #-}

    -- | Deprecated alias for 'bind'.
    bindSocket :: Socket    -- Unconnected Socket
               -> SockAddr  -- Address to Bind to
               -> IO ()
    bindSocket = bind

    {-# DEPRECATED sClose "use 'close'" #-}

    -- | Deprecated alias for 'close'.
    sClose :: Socket -> IO ()
    sClose = close

    {-# DEPRECATED sIsConnected "use 'isConnected'" #-}

    -- | Deprecated alias for 'isConnected'.
    sIsConnected :: Socket -> IO Bool
    sIsConnected = isConnected

    {-# DEPRECATED sIsBound "use 'isBound'" #-}

    -- | Deprecated alias for 'isBound'.
    sIsBound :: Socket -> IO Bool
    sIsBound = isBound

    {-# DEPRECATED sIsListening "use 'isListening'" #-}

    -- | Deprecated alias for 'isListening'.
    sIsListening :: Socket -> IO Bool
    sIsListening = isListening

    {-# DEPRECATED sIsReadable "use 'isReadable'" #-}

    -- | Deprecated alias for 'isReadable'.
    sIsReadable  :: Socket -> IO Bool
    sIsReadable = isReadable

    {-# DEPRECATED sIsWritable "use 'isWritable'" #-}

    -- | Deprecated alias for 'isWritable'.
    sIsWritable  :: Socket -> IO Bool
    sIsWritable = isWritable