diff --git a/Control/Concurrent/Barrier.hs b/Control/Concurrent/Barrier.hs
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--- /dev/null
+++ b/Control/Concurrent/Barrier.hs
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+{-# LANGUAGE DoAndIfThenElse #-}
+module Control.Concurrent.Barrier
+    ( barrier
+    , latchBarrier
+    ) where
+
+import Control.Monad (forM_)
+import Control.Concurrent.MVar
+
+barrier' :: (Int -> Int) -> Int -> IO (IO ())
+barrier' reset count = do
+  b <- newMVar (count, [])
+  return $ do
+    w <- modifyMVar b $ \(c, waiting) ->
+           case c of
+             0 -> return ((0, []), Nothing)
+             1 -> do forM_ waiting $ flip putMVar ()
+                     return ((reset count, []), Nothing)
+             _ -> do w <- newEmptyMVar
+                     return ((c-1, w:waiting), Just w)
+
+    maybe (return ()) takeMVar w
+
+-- | Self-resetting barrier.  'barrier' blocks until a specified
+-- number of threads have reached it, and then they are all allowed to
+-- run.  The barrier is then reset so that a further 'count' threads
+-- can block on it.  Typical usage is:
+-- 
+-- > do b <- barrier 3
+-- >    forkIO $ b >> putStrLn "1"  -- blocked
+-- >    forkIO $ b >> putStrLn "2"  -- blocked
+-- >    forkIO $ b >> putStrLn "3"  -- all three threads run
+barrier :: Int -- ^ count - number of threads required before barrier is opened
+        -> IO (IO ())
+barrier = barrier' id
+
+-- | Latching barrier.  This is the same as 'barrier', except once the
+-- barrier has opened (the requisite number of threads has reached
+-- it), it remains open, allowing all subsequent threads through
+-- unblocked.
+latchBarrier :: Int -- ^ count - number of threads required before barrier is opened
+             -> IO (IO ())
+latchBarrier = barrier' (const 0)
diff --git a/LICENSE b/LICENSE
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--- /dev/null
+++ b/LICENSE
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+Copyright (c)2011, Jeremy Fitzhardinge
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Jeremy Fitzhardinge nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/Setup.hs b/Setup.hs
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--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/concurrent-barrier.cabal b/concurrent-barrier.cabal
new file mode 100644
--- /dev/null
+++ b/concurrent-barrier.cabal
@@ -0,0 +1,62 @@
+-- concurrent-barrier.cabal auto-generated by cabal init. For
+-- additional options, see
+-- http://www.haskell.org/cabal/release/cabal-latest/doc/users-guide/authors.html#pkg-descr.
+-- The name of the package.
+Name:                concurrent-barrier
+
+-- The package version. See the Haskell package versioning policy
+-- (http://www.haskell.org/haskellwiki/Package_versioning_policy) for
+-- standards guiding when and how versions should be incremented.
+Version:             0.1
+
+-- A short (one-line) description of the package.
+Synopsis:            Simple thread barriers
+
+-- A longer description of the package.
+Description: A very simple package providing thread barriers.
+
+-- URL for the project homepage or repository.
+Homepage:            https://github.com/jsgf/concurrent-barrier
+
+-- The license under which the package is released.
+License:             BSD3
+
+-- The file containing the license text.
+License-file:        LICENSE
+
+-- The package author(s).
+Author:              Jeremy Fitzhardinge
+
+-- An email address to which users can send suggestions, bug reports,
+-- and patches.
+Maintainer:          jeremy@goop.org
+
+-- A copyright notice.
+-- Copyright:           
+
+Category:            Concurrency
+
+Build-type:          Simple
+
+-- Extra files to be distributed with the package, such as examples or
+-- a README.
+-- Extra-source-files:  
+
+-- Constraint on the version of Cabal needed to build this package.
+Cabal-version:       >=1.2
+
+Library
+  -- Modules exported by the library.
+  Exposed-modules:     Control.Concurrent.Barrier
+  ghc-options:      -Wall
+  
+  -- Packages needed in order to build this package.
+  Build-depends:       
+      base >= 3 && < 5
+ 
+  -- Modules not exported by this package.
+  -- Other-modules:       
+  
+  -- Extra tools (e.g. alex, hsc2hs, ...) needed to build the source.
+  -- Build-tools:         
+