--
-- A storable array is an IO-mutable array which stores its
-- contents in a contiguous memory block living in the C
--- heap. Elements are stored according to the class Storable.
+-- heap. Elements are stored according to the class 'Storable'.
-- You can obtain the pointer to the array contents to manipulate
-- elements from languages like C.
--
--- It's similar to IOUArray but slower. Its advantage is that
--- it's compatible with C.
+-- It is similar to 'Data.Array.IO.IOUArray' but slower.
+-- Its advantage is that it's compatible with C.
--
-----------------------------------------------------------------------------
module Data.Array.Storable (
- -- Array type:
+ -- * Arrays of 'Storable' things.
StorableArray, -- data StorableArray index element
-- -- index type must be in class Ix
-- -- element type must be in class Storable
- -- Module MArray provides the interface of storable arrays.
- -- They are instances of class MArray (with IO monad).
+ -- * Overloaded mutable array interface
+ -- | Module "Data.Array.MArray" provides the interface of storable arrays.
+ -- They are instances of class 'MArray' (with the 'IO' monad).
module Data.Array.MArray,
- -- The pointer to the array contents is obtained by withStorableArray.
- -- The idea is similar to ForeignPtr (used internally here). The
- -- pointer should be used only during execution of the IO action
- -- retured by the function passed as argument to withStorableArray:
+ -- * Accessing the pointer to the array contents
withStorableArray, -- :: StorableArray i e -> (Ptr e -> IO a) -> IO a
- -- If you want to use it afterwards, ensure that you
- -- touchStorableArray after the last use of the pointer,
- -- so the array is not freed too early:
touchStorableArray -- :: StorableArray i e -> IO ()
)
where
import Data.Array.MArray
import Foreign hiding (newArray)
+-- |The array type
data StorableArray i e = StorableArray !i !i !(ForeignPtr e)
instance HasBounds StorableArray where
unsafeWrite (StorableArray _ _ fp) i e =
withForeignPtr fp $ \a -> pokeElemOff a i e
+-- |The pointer to the array contents is obtained by 'withStorableArray'.
+-- The idea is similar to 'ForeignPtr' (used internally here).
+-- The pointer should be used only during execution of the 'IO' action
+-- retured by the function passed as argument to 'withStorableArray'.
withStorableArray :: StorableArray i e -> (Ptr e -> IO a) -> IO a
withStorableArray (StorableArray _ _ fp) f = withForeignPtr fp f
+-- |If you want to use it afterwards, ensure that you
+-- 'touchStorableArray' after the last use of the pointer,
+-- so the array is not freed too early.
touchStorableArray :: StorableArray i e -> IO ()
touchStorableArray (StorableArray _ _ fp) = touchForeignPtr fp
------------------------------------------------------------------------
{- |
-The computation @rawSystem cmd args@ runs the operating system command
+The computation @'rawSystem' cmd args@ runs the operating system command
whose file name is @cmd@, passing it the arguments @args@. It
bypasses the shell, so that @cmd@ should see precisely the argument
strings @args@, with no funny escaping or shell meta-syntax expansion.
(Unix users will recognise this behaviour
as @execvp@, and indeed that's how it's implemented.)
-It will therefore behave more portably between operating systems than @system@.
+It will therefore behave more portably between operating systems than 'system'.
-The return codes are the same as for @system@.
+The return codes are the same as for 'system'.
-}
rawSystem :: FilePath -> [String] -> IO ExitCode