1 files changed, 24 insertions, 0 deletions
diff --git a/testsuite/tests/lib/IO/hDuplicateTo001.hs b/testsuite/tests/lib/IO/hDuplicateTo001.hs
new file mode 100644
index 0000000000..5a1484a012
--- /dev/null
+++ b/testsuite/tests/lib/IO/hDuplicateTo001.hs
@@ -0,0 +1,24 @@
+import GHC.Handle
+import GHC.IOBase
+import System.IO
+import Control.Concurrent.MVar
+import Data.Typeable
+import qualified GHC.IO.FD as FD
+
+main = do
+   h <- openFile "tmp" WriteMode
+   hDuplicateTo h stdout
+   
+   fdh <- getfd h
+   fdstdout <- getfd stdout
+   hPutStrLn stderr ("h: " ++ show (fdh /= fdstdout) ++ "\nstdout: " ++ show fdstdout)
+
+   hClose h
+   putStrLn "bla"
+
+
+getfd h@(FileHandle _ mvar) = do
+  withMVar mvar $ \h__@Handle__{haDevice=dev} ->
+   case cast dev of
+     Just fd -> return (FD.fdFD fd)
+     Nothing -> error "getfd"