data ByteCount  -- instances of : Eq Ord Num Real Integral Ix Enum Show

A ByteCount is a primitive of type unsigned. At a minimum, an conforming implementation must support values in the range [0, UINT_MAX].

data ClockTick  -- instances of : Eq Ord Num Real Integral Ix Enum Show

A ClockTick is a primitive of type clock_t, which is used to measure intervals of time in fractions of a second. The resolution is determined by getSysVar ClockTick.

data DeviceID  -- instances of : Eq Ord Num Real Integral Ix Enum Show

A DeviceID is a primitive of type dev_t. It must be an arithmetic type.

data EpochTime -- instances of : Eq Ord Num Real Integral Ix Enum Show

A EpochTime is a primitive of type time_t, which is used to measure seconds since the Epoch. At a minimum, the implementation must support values in the range [0, INT_MAX].

data FileID -- instances of : Eq Ord Num Real Integral Ix Enum Show

A FileID is a primitive of type ino_t. It must be an arithmetic type.

data FileMode -- instance of : Eq

A FileMode is a primitive of type mode_t. It must be an arithmetic type.

data FileOffset -- instances of : Eq Ord Num Real Integral Ix Enum Show

A FileOffset is a primitive of type off_t. It must be an arithmetic type.

data GroupID -- instances of : Eq Ord Num Real Integral Ix Enum Show

A GroupID is a primitive of type gid_t. It must be an arithmetic type.

data Limit -- instances of : Eq Ord Num Real Integral Ix Enum Show

A Limit is a primitive of type long. At a minimum, the implementation must support values in the range [LONG_MIN, LONG_MAX].

data LinkCount -- instances of : Eq Ord Num Real Integral Ix Enum Show

A LinkCount is a primitive of type nlink_t. It must be an arithmetic type.

data ProcessID -- instances of : Eq Ord Num Real Integral Ix Enum Show
type ProcessGroupID = ProcessID

A ProcessID is a primitive of type pid_t. It must be a signed arithmetic type.

data UserID -- instances of : Eq Ord Num Real Integral Ix Enum Show

A UserID is a primitive of type uid_t. It must be an arithmetic type.

data DirStream

A DirStream is a primitive of type DIR *.

data FileStatus

A FileStatus is a primitive of type struct stat.

data GroupEntry

A GroupEntry is a primitive of type struct group.

data ProcessTimes

ProcessTimes is a primitive structure containing a clock_t and a struct tms.

data SignalSet

An SignalSet is a primitive of type sigset_t.

data SystemID

A SystemID is a primitive of type struct utsname.

data TerminalAttributes

TerminalAttributes is a primitive of type struct termios.

data UserEntry

A UserEntry is a primitive of type struct passwd.

data BaudRate = B0 | B50 | B75 | B110 | B134 | B150 | B200 | B300 | B600
              | B1200 | B1800 | B2400 | B4800 | B9600 | B19200 | B38400
              deriving (Eq, Show)

data Fd 

instance Eq Fd 
instance Show Fd

intToFd :: Int -> Fd -- use with care.
fdToInt :: Fd -> Int     -- ditto.

data FdOption = AppendOnWrite
              | CloseOnExec
              | NonBlockingRead

data ControlCharacter = EndOfFile
                      | EndOfLine
                      | Erase
                      | Interrupt
                      | Kill
                      | Quit
                      | Suspend
                      | Start
                      | Stop

type ErrorCode = Int

type FileLock = (LockRequest, SeekMode, FileOffset, FileOffset)
--                            whence    start       length

data FlowAction = SuspendOutput | RestartOutput | TransmitStop | TransmitStart

data Handler = Default | Ignore | Catch (IO ())

data LockRequest = ReadLock | WriteLock | Unlock
                 deriving (Eq, Show)

data OpenMode = ReadOnly | WriteOnly | ReadWrite

data PathVar = LinkLimit
             | InputLineLimit
             | InputQueueLimit
             | FileNameLimit
             | PathNameLimit
             | PipeBufferLimit
             | SetOwnerAndGroupIsRestricted
             | FileNamesAreNotTruncated

data QueueSelector = InputQueue | OutputQueue | BothQueues

type Signal = Int

data SysVar = ArgumentLimit
            | ChildLimit
            | ClockTick
            | GroupLimit
            | OpenFileLimit
            | PosixVersion
            | HasSavedIDs
            | HasJobControl

data TerminalMode = InterruptOnBreak       -- BRKINT
                | MapCRtoLF                -- ICRNL
                | IgnoreBreak              -- IGNBRK
                | IgnoreCR                 -- IGNCR
                | IgnoreParityErrors       -- IGNPAR
                | MapLFtoCR                -- INLCR
                | CheckParity              -- INPCK
                | StripHighBit             -- ISTRIP
                | StartStopInput           -- IXOFF
                | StartStopOutput          -- IXON
                | MarkParityErrors         -- PARMRK
                | ProcessOutput            -- OPOST
                | LocalMode                -- CLOCAL
                | ReadEnable               -- CREAD
                | TwoStopBits              -- CSTOPB
                | HangupOnClose            -- HUPCL
                | EnableParity             -- PARENB
                | OddParity                -- PARODD
                | EnableEcho               -- ECHO
                | EchoErase                -- ECHOE
                | EchoKill                 -- ECHOK
                | EchoLF                   -- ECHONL
                | ProcessInput             -- ICANON
                | ExtendedFunctions        -- IEXTEN
                | KeyboardInterrupts       -- ISIG
                | NoFlushOnInterrupt       -- NOFLSH
                | BackgroundWriteInterrupt -- TOSTOP

data TerminalState = Immediately | WhenDrained | WhenFlushed

data ProcessStatus = Exited ExitCode 
                   | Terminated Signal 
                   | Stopped Signal
                   deriving (Eq, Show)