[project @ 2005-12-13 13:28:53 by simonmar]

Only Streams can be DuplexHandles, not RawDevices.

diff --git a/GHC/Handle.hs b/GHC/Handle.hs
index 0e9b3be..52bf8cd 100644 (file)
--- a/GHC/Handle.hs
+++ b/GHC/Handle.hs
@@ -924,16 +924,21 @@ openFd fd mb_fd_type is_socket filepath mode binary = do
                                   "file is locked" Nothing)
 #endif
           mkFileHandle fd is_socket filepath ha_type binary
-        -- Stream or RawDevice
-       Stream    -> mkIt ha_type
-       RawDevice -> mkIt ha_type
+
+       Stream
+          -- only *Streams* can be DuplexHandles.  Other read/write
+          -- Handles must share a buffer.
+          | ReadWriteHandle <- ha_type -> 
+               mkDuplexHandle fd is_socket filepath binary
+          | otherwise ->
+               mkFileHandle   fd is_socket filepath ha_type binary
+
+       RawDevice -> 
+               mkFileHandle fd is_socket filepath ha_type binary
+
        _ ->
          ioException (IOError Nothing UnsupportedOperation "openFd"
                                   "unknown file type" Nothing) 
-     where
-      mkIt ht
-       | isReadWriteHandleType ht = mkDuplexHandle fd is_socket filepath binary
-       | otherwise                = mkFileHandle   fd is_socket filepath ht binary
 
 fdToHandle :: FD -> IO Handle
 fdToHandle fd = do