{-# LANGUAGE ForeignFunctionInterface #-}
{-# OPTIONS_GHC -fno-warn-unused-imports #-}
{-# OPTIONS_GHC -XRecordWildCards #-}
#if __GLASGOW_HASKELL__ >= 701
{-# LANGUAGE Trustworthy #-}
#endif
-----------------------------------------------------------------------------
-- |
-- Module      :  System.Posix.IO.ByteString
-- Copyright   :  (c) The University of Glasgow 2002
-- License     :  BSD-style (see the file libraries/base/LICENSE)
-- 
-- Maintainer  :  libraries@haskell.org
-- Stability   :  provisional
-- Portability :  non-portable (requires POSIX)
--
-- POSIX IO support.  These types and functions correspond to the unix
-- functions open(2), close(2), etc.  For more portable functions
-- which are more like fopen(3) and friends from stdio.h, see
-- "System.IO".
--
-----------------------------------------------------------------------------

#include "HsUnix.h"

module System.Posix.IO.ByteString (
    -- * Input \/ Output

    -- ** Standard file descriptors
    stdInput, stdOutput, stdError,

    -- ** Opening and closing files
    OpenMode(..),
    OpenFileFlags(..), defaultFileFlags,
    openFd, createFile,
    closeFd,

    -- ** Reading\/writing data
    -- |Programmers using the 'fdRead' and 'fdWrite' API should be aware that
    -- EAGAIN exceptions may occur for non-blocking IO!

    fdRead, fdWrite,
    fdReadBuf, fdWriteBuf,

    -- ** Seeking
    fdSeek,

    -- ** File options
    FdOption(..),
    queryFdOption,
    setFdOption,

    -- ** Locking
    FileLock,
    LockRequest(..),
    getLock,  setLock,
    waitToSetLock,

    -- ** Pipes
    createPipe,

    -- ** Duplicating file descriptors
    dup, dupTo,

    -- ** Converting file descriptors to\/from Handles
    handleToFd,
    fdToHandle,  

  ) where

import System.Posix.Types
import System.Posix.IO.Common
import Foreign.C hiding (
     throwErrnoPath,
     throwErrnoPathIf,
     throwErrnoPathIf_,
     throwErrnoPathIfNull,
     throwErrnoPathIfMinus1,
     throwErrnoPathIfMinus1_ )

import System.Posix.ByteString.FilePath


-- |Open and optionally create this file.  See 'System.Posix.Files'
-- for information on how to use the 'FileMode' type.
openFd :: RawFilePath
       -> OpenMode
       -> Maybe FileMode -- ^Just x => creates the file with the given modes, Nothing => the file must exist.
       -> OpenFileFlags
       -> IO Fd
openFd name how maybe_mode flags = do
   withFilePath name $ \str -> do
     throwErrnoPathIfMinus1Retry "openFd" name $
       open_ str how maybe_mode flags

-- |Create and open this file in WriteOnly mode.  A special case of
-- 'openFd'.  See 'System.Posix.Files' for information on how to use
-- the 'FileMode' type.

createFile :: RawFilePath -> FileMode -> IO Fd
createFile name mode
  = openFd name WriteOnly (Just mode) defaultFileFlags{ trunc=True }