{-# LANGUAGE CApiFFI #-} #if __GLASGOW_HASKELL__ >= 709 {-# LANGUAGE Safe #-} #else {-# LANGUAGE Trustworthy #-} #endif ----------------------------------------------------------------------------- -- | -- Module : System.Posix.Fcntl -- Copyright : (c) The University of Glasgow 2014 -- License : BSD-style (see the file LICENSE) -- -- Maintainer : libraries@haskell.org -- Stability : provisional -- Portability : non-portable (requires POSIX) -- -- POSIX file control support -- -- /Since: 2.7.1.0/ ----------------------------------------------------------------------------- #include "HsUnix.h" module System.Posix.Fcntl ( -- * File allocation Advice(..), fileAdvise, fileAllocate, ) where #if HAVE_POSIX_FALLOCATE || HAVE_POSIX_FADVISE import Foreign.C #endif import System.Posix.Types #if !HAVE_POSIX_FALLOCATE import System.IO.Error ( ioeSetLocation ) import GHC.IO.Exception ( unsupportedOperation ) #endif -- ----------------------------------------------------------------------------- -- File control -- | Advice parameter for 'fileAdvise' operation. -- -- For more details, see documentation of @posix_fadvise(2)@. -- -- /Since: 2.7.1.0/ data Advice = AdviceNormal | AdviceRandom | AdviceSequential | AdviceWillNeed | AdviceDontNeed | AdviceNoReuse deriving Eq -- | Performs @posix_fadvise(2)@ operation on file-descriptor. -- -- If platform does not provide @posix_fadvise(2)@ 'fileAdvise' -- becomes a no-op. -- -- (use @#if HAVE_POSIX_FADVISE@ CPP guard to detect availability) -- -- /Since: 2.7.1.0/ fileAdvise :: Fd -> FileOffset -> FileOffset -> Advice -> IO () #if HAVE_POSIX_FADVISE fileAdvise fd off len adv = do throwErrnoIfMinus1_ "fileAdvise" (c_posix_fadvise (fromIntegral fd) (fromIntegral off) (fromIntegral len) (packAdvice adv)) foreign import capi safe "fcntl.h posix_fadvise" c_posix_fadvise :: CInt -> COff -> COff -> CInt -> IO CInt packAdvice :: Advice -> CInt packAdvice AdviceNormal = (#const POSIX_FADV_NORMAL) packAdvice AdviceRandom = (#const POSIX_FADV_RANDOM) packAdvice AdviceSequential = (#const POSIX_FADV_SEQUENTIAL) packAdvice AdviceWillNeed = (#const POSIX_FADV_WILLNEED) packAdvice AdviceDontNeed = (#const POSIX_FADV_DONTNEED) packAdvice AdviceNoReuse = (#const POSIX_FADV_NOREUSE) #else fileAdvise _ _ _ _ = return () #endif -- | Performs @posix_fallocate(2)@ operation on file-descriptor. -- -- Throws 'IOError' (\"unsupported operation\") if platform does not -- provide @posix_fallocate(2)@. -- -- (use @#if HAVE_POSIX_FALLOCATE@ CPP guard to detect availability). -- -- /Since: 2.7.1.0/ fileAllocate :: Fd -> FileOffset -> FileOffset -> IO () #if HAVE_POSIX_FALLOCATE fileAllocate fd off len = do throwErrnoIfMinus1_ "fileAllocate" (c_posix_fallocate (fromIntegral fd) (fromIntegral off) (fromIntegral len)) foreign import capi safe "fcntl.h posix_fallocate" c_posix_fallocate :: CInt -> COff -> COff -> IO CInt #else {-# WARNING fileAllocate "operation will throw 'IOError' \"unsupported operation\" (CPP guard: @#if HAVE_POSIX_FALLOCATE@)" #-} fileAllocate _ _ _ = ioError (ioeSetLocation unsupportedOperation "fileAllocate") #endif