diff --git a/Setup.lhs b/Setup.lhs
new file mode 100644
--- /dev/null
+++ b/Setup.lhs
@@ -0,0 +1,3 @@
+#!/usr/bin/env runhaskell
+> import Distribution.Simple
+> main = defaultMain
diff --git a/System/Locale/SetLocale.hsc b/System/Locale/SetLocale.hsc
new file mode 100644
--- /dev/null
+++ b/System/Locale/SetLocale.hsc
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+{-# LANGUAGE ForeignFunctionInterface #-}
+
+module System.Locale.SetLocale (
+    Category(..),
+    categoryToCInt,
+    setLocale
+) where
+
+import Foreign.Ptr
+import Foreign.C.Types
+import Foreign.C.String
+
+import Data.Typeable
+
+-- | A type representing the various locale categories. See @man 7 locale@.
+data Category
+    = LC_ALL
+    | LC_COLLATE
+    | LC_CTYPE
+    | LC_MESSAGES
+    | LC_MONETARY
+    | LC_NUMERIC
+    | LC_TIME
+    deriving (Eq, Ord, Read, Show, Enum, Bounded)
+
+instance Typeable Category where
+    typeOf _ = mkTyConApp (mkTyCon "System.Locale.SetLocale.Category") []
+
+#include <locale.h>
+
+-- | Convert a 'Category' to the corresponding system-specific @LC_*@ code.
+-- You probably don't need this function.
+categoryToCInt :: Category -> CInt
+categoryToCInt LC_ALL = #const LC_ALL
+categoryToCInt LC_COLLATE = #const LC_COLLATE
+categoryToCInt LC_CTYPE = #const LC_CTYPE
+categoryToCInt LC_MESSAGES = #const LC_MESSAGES
+categoryToCInt LC_MONETARY = #const LC_MONETARY
+categoryToCInt LC_NUMERIC = #const LC_NUMERIC
+categoryToCInt LC_TIME = #const LC_TIME
+
+ptr2str :: Ptr CChar -> IO (Maybe String)
+ptr2str p
+    | p == nullPtr = return Nothing
+    | otherwise = fmap Just $ peekCString p
+
+str2ptr :: Maybe String -> (Ptr CChar -> IO a) -> IO a
+str2ptr Nothing  f = f nullPtr
+str2ptr (Just s) f = withCString s f
+
+foreign import ccall unsafe "locale.h setlocale" c_setlocale :: CInt -> Ptr CChar -> IO (Ptr CChar)
+
+-- | A Haskell version of @setlocale()@. See @man 3 setlocale@.
+setLocale :: Category -> Maybe String -> IO (Maybe String)
+setLocale cat str =
+    str2ptr str $ \p -> c_setlocale (categoryToCInt cat) p >>= ptr2str
diff --git a/setlocale.cabal b/setlocale.cabal
new file mode 100644
--- /dev/null
+++ b/setlocale.cabal
@@ -0,0 +1,15 @@
+Name:		setlocale
+Version:	0.0.3
+Cabal-Version:	>= 1.2
+Build-Type:	Simple
+License:	PublicDomain
+Author:		Lukas Mai
+Maintainer:	l.mai @web.de
+Synopsis:	A Haskell interface to setlocale()
+Description:	A Haskell interface to @setlocale()@.
+Category:	System
+
+Library
+  Exposed-Modules:	System.Locale.SetLocale
+  Build-Depends:	base
+  Ghc-Options:		-O2 -Wall