X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=System%2FIO.hs;h=ab52244eff0560556fc69178957a350953c30da4;hb=509f28cc93b980d30aca37008cbe66c677a0d6f6;hp=a543f2b1f6c27454f635fef63d0817d34eba3396;hpb=4dc0a6fa50f56444c76e84387a16b179df2549ee;p=ghc-base.git

diff --git a/System/IO.hs b/System/IO.hs
index a543f2b..ab52244 100644
--- a/System/IO.hs
+++ b/System/IO.hs
@@ -1,4 +1,5 @@
-{-# OPTIONS_GHC -XNoImplicitPrelude #-}
+{-# LANGUAGE CPP, NoImplicitPrelude #-}
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  System.IO
@@ -25,6 +26,15 @@ module System.IO (
 
     Handle,             -- abstract, instance of: Eq, Show.
 
+    -- | GHC note: a 'Handle' will be automatically closed when the garbage
+    -- collector detects that it has become unreferenced by the program.
+    -- However, relying on this behaviour is not generally recommended:
+    -- the garbage collector is unpredictable.  If possible, use
+    -- an explicit 'hClose' to close 'Handle's when they are no longer
+    -- required.  GHC does not currently attempt to free up file
+    -- descriptors when they have run out, it is your responsibility to
+    -- ensure that this doesn't happen.
+
     -- ** Standard handles
 
     -- | Three handles are allocated during program initialisation,
@@ -235,13 +245,12 @@ import System.Posix.Types
 
 #ifdef __GLASGOW_HASKELL__
 import GHC.Base
-import GHC.Real
-import GHC.IO hiding ( onException )
+import GHC.IO hiding ( bracket, onException )
 import GHC.IO.IOMode
 import GHC.IO.Handle.FD
 import qualified GHC.IO.FD as FD
 import GHC.IO.Handle
-import GHC.IO.Handle.Text ( hGetBufSome )
+import GHC.IO.Handle.Text ( hGetBufSome, hPutStrLn )
 import GHC.IORef
 import GHC.IO.Exception ( userError )
 import GHC.IO.Encoding
@@ -317,8 +326,7 @@ putStr s        =  hPutStr stdout s
 -- | The same as 'putStr', but adds a newline character.
 
 putStrLn        :: String -> IO ()
-putStrLn s      =  do putStr s
-                      putChar '\n'
+putStrLn s      =  hPutStrLn stdout s
 
 -- | The 'print' function outputs a value of any printable type to the
 -- standard output device.
@@ -416,13 +424,6 @@ readIO s        =  case (do { (x,t) <- reads s ;
 hReady          :: Handle -> IO Bool
 hReady h        =  hWaitForInput h 0
 
--- | The same as 'hPutStr', but adds a newline character.
-
-hPutStrLn       :: Handle -> String -> IO ()
-hPutStrLn hndl str = do
- hPutStr  hndl str
- hPutChar hndl '\n'
-
 -- | Computation 'hPrint' @hdl t@ writes the string representation of @t@
 -- given by the 'shows' function to the file or channel managed by @hdl@
 -- and appends a newline.
@@ -440,7 +441,9 @@ hPrint hdl      =  hPutStrLn hdl . show
 -- | @'withFile' name mode act@ opens a file using 'openFile' and passes
 -- the resulting handle to the computation @act@.  The handle will be
 -- closed on exit from 'withFile', whether by normal termination or by
--- raising an exception.
+-- raising an exception.  If closing the handle raises an exception, then
+-- this exception will be raised by 'withFile' rather than any exception
+-- raised by 'act'.
 withFile :: FilePath -> IOMode -> (Handle -> IO r) -> IO r
 withFile name mode = bracket (openFile name mode) hClose
 
@@ -564,7 +567,7 @@ openTempFile' loc tmp_dir template binary mode = do
            else ioError (errnoToIOError loc errno Nothing (Just tmp_dir))
        else do
 
-         (fD,fd_type) <- FD.mkFD (fromIntegral fd) ReadWriteMode Nothing{-no stat-}
+         (fD,fd_type) <- FD.mkFD fd ReadWriteMode Nothing{-no stat-}
                               False{-is_socket-} 
                               True{-is_nonblock-}
 
@@ -615,8 +618,7 @@ foreign import ccall "getpid" c_getpid :: IO Int
 -- $locking
 -- Implementations should enforce as far as possible, at least locally to the
 -- Haskell process, multiple-reader single-writer locking on files.
--- That is, /there may either be many handles on the same file which manage
--- input, or just one handle on the file which manages output/.  If any
+-- That is, /there may either be many handles on the same file which manage input, or just one handle on the file which manages output/.  If any
 -- open or semi-closed handle is managing a file for output, no new
 -- handle can be allocated for that file.  If any open or semi-closed
 -- handle is managing a file for input, new handles can only be allocated