diff --git a/HFlags.hs b/HFlags.hs
--- a/HFlags.hs
+++ b/HFlags.hs
@@ -34,8 +34,8 @@
 -- the toplevel @flags_name@ constants.  Those can be used purely
 -- throughout the program.
 --
--- At the beginning of the @main@ function, @$initHFlags "program
--- description"@ has to be called to initialize the flags.  All flags
+-- At the beginning of the @main@ function, @$'initHFlags' \"program
+-- description\"@ has to be called to initialize the flags.  All flags
 -- will be initialized that are transitively reachable via imports
 -- from @main@.  This means, that any Haskell package can easily
 -- define command line flags with @HFlags@.  This feature is
@@ -62,10 +62,11 @@
 -- >   where
 -- >     greet = putStrLn $ "Hello " ++ flags_name ++ ", very nice to meet you!"
 --
--- At @initHFlags@ time, the library also tries to gather flags out of
+-- At 'initHFlags' time, the library also tries to gather flags out of
 -- environment variables.  @HFLAGS_verbose=True@ is equivalent to
--- specify --verbose=True.  This environment feature only works with
--- long options and the user has to specify a value even for Bools.
+-- specifying @--verbose=True@ on the command line.  This environment
+-- feature only works with long options and the user has to specify a
+-- value even for @Bool@s.
 --
 -- /Since version 0.2, you mustn't put the initHFlags in a parentheses with the program description.  Just/ @$initHFlags@, /it's cleaner./
 
@@ -80,10 +81,12 @@
   initHFlagsDependentDefaults,
   -- * For easy access to arguments, after initHFlags has been called
   arguments,
+  undefinedOptions,
   -- * For debugging, shouldn't be used in production code
   Flag(..),
   globalHFlags,
-  globalArguments
+  globalArguments,
+  globalUndefinedOptions
   ) where
 
 -- TODOs:
@@ -121,7 +124,7 @@
             , fArgType :: String
             , fDescription :: String
             , fModuleName :: String
-            , fCheck :: IO () -- ^ function to evaluate in 'initFlags'
+            , fCheck :: IO () -- ^ function to evaluate in @initFlags@
                               -- to force syntax check of the argument.
             }
 
@@ -242,6 +245,16 @@
 instance FlagType Bool where
   defineFlag n v = defineCustomFlag n [| v :: Bool |] "BOOL" [| boolRead |] [| boolShow |]
 
+charShow :: Char -> String
+charShow x = x:[]
+
+charRead :: String -> Char
+charRead [x] = x
+charRead s = error $ "Unable to parse string as char: " ++ s
+
+instance FlagType Char where
+  defineFlag n v = defineCustomFlag n [| v :: Char |] "CHAR" [| charRead |] [| charShow |]
+
 instance FlagType Int where
   defineFlag n v = defineEQFlag n [| v :: Int |] "INT"
 
@@ -262,19 +275,19 @@
     let s = Data.Text.unpack v
     in defineCustomFlag n [| Data.Text.pack s :: Data.Text.Text |] "TEXT" [| Data.Text.pack |] [| Data.Text.unpack |]
 
--- | A global "IORef" for the communication between @initHFlags@ and
+-- | A global 'IORef' for the communication between 'initHFlags' and
 -- @flags_*@.  This is a map between flag name and current value.
 {-# NOINLINE globalHFlags #-}
 globalHFlags :: IORef (Maybe (Map String String))
 globalHFlags = unsafePerformIO $ newIORef Nothing
 
--- | A global "IORef" for the easy access to the arguments.
+-- | A global 'IORef' for the easy access to the arguments.
 {-# NOINLINE globalArguments #-}
 globalArguments :: IORef (Maybe [String])
 globalArguments = unsafePerformIO $ newIORef Nothing
 
 -- | Contains the non-parsed, non-option parts of the command line,
--- the arguments.  Can only be used after @initHFlags@ has been called.
+-- the arguments.  Can only be used after 'initHFlags' has been called.
 {-# NOINLINE arguments #-}
 arguments :: [String]
 arguments = unsafePerformIO $ do
@@ -283,6 +296,25 @@
     Just args -> return $ args
     Nothing -> error $ "HFlags.arguments used before calling initHFlags."
 
+-- | A global 'IORef' for the easy access to the undefined options, if
+-- @--undefok@ is used.  Useful, if you have to pass these options to
+-- another library, e.g. @criterion@ or @GTK@.
+{-# NOINLINE globalUndefinedOptions #-}
+globalUndefinedOptions :: IORef (Maybe [String])
+globalUndefinedOptions = unsafePerformIO $ newIORef Nothing
+
+-- | Contains the non-parsed, option parts of the command line, if
+-- @--undefok@ is in use.  This can be useful, when you have to pass
+-- these options to other libraries, e.g. @criterion@ or @GTK@.  Can
+-- only be used after 'initHFlags' has been called.
+{-# NOINLINE undefinedOptions #-}
+undefinedOptions :: [String]
+undefinedOptions = unsafePerformIO $ do
+  margs <- readIORef globalUndefinedOptions
+  case margs of
+    Just args -> return $ args
+    Nothing -> error $ "HFlags.globalUndefOpts used before calling initHFlags."
+
 lookupFlag :: String -> String -> String
 lookupFlag fName fModuleName = unsafePerformIO $ do
   flags <- readIORef globalHFlags
@@ -296,12 +328,13 @@
 -- | A function that gets three alists and returns a new one.
 type DependentDefaults = AList -> AList -> AList -> AList
 
--- | Initializes @globalHFlags@ and returns the non-option arguments.
+-- | Initializes 'globalHFlags' and returns the non-option arguments.
 initFlags :: DependentDefaults -> String -> [FlagData] -> [String] -> IO [String]
 initFlags dependentDefaults progDescription flags args = do
   doHelp
-  let (opts, nonopts, errs) | doUndefok = (\(a,b,_,c) -> (a,b,c)) $ getOpt' Permute getOptFlags args
-                            | otherwise = getOpt Permute getOptFlags args
+  let (opts, nonopts, undefopts, errs)
+        | doUndefok = getOpt' Permute getOptFlags args
+        | otherwise = (\(a,b,c) -> (a,b,[],c)) $ getOpt Permute getOptFlags args
   when (not $ null errs) $ do
     mapM_ (hPutStrLn stderr) errs
     exitFailure
@@ -311,6 +344,7 @@
   let depdef = dependentDefaults defaults envDefaults opts
   writeIORef globalHFlags $ Just $ Map.fromList $ defaults ++ depdef ++ envDefaults ++ opts
   writeIORef globalArguments $ Just nonopts
+  writeIORef globalUndefinedOptions $ Just undefopts
   mapM_ forceFlag flags
   return nonopts
     where
@@ -318,7 +352,7 @@
       helpOption = Option "h" ["help", "usage", "version"] (NoArg ("", "")) "Display help and version information."
       doHelp = case getOpt Permute [helpOption] args of
         ([], _, _) -> return ()
-        _ -> do putStrLn $ usageInfo (progDescription ++ "\n") (helpOption:undefokOption:getOptFlags)
+        _ -> do putStrLn $ usageInfo (progDescription ++ "\n") (helpOption:getOptFlags)
                 exitFailure
 
       undefokOption = Option "" ["undefok"] (NoArg ("", "")) "Whether to fail on unrecognized command line options."
@@ -331,9 +365,11 @@
         | otherwise = ReqArg (\a -> (fName, a)) fArgType
 
       -- compute GetOpt compatible [Option] structure from flags ([FlagData])
-      getOptFlags = flip map flags $ \flagData@(FlagData { fName, fShort, fDefValue, fDescription, fModuleName }) ->
-        Option (maybeToList fShort) [fName] (flagToGetOptArgDescr flagData)
-               (fDescription ++ " (default: " ++ fDefValue ++ ", from module: " ++ fModuleName ++ ")")
+      getOptFlags = undefokOption:
+        (flip map flags $ \flagData@(FlagData { fName, fShort, fDefValue, fDescription, fModuleName }) ->
+         Option (maybeToList fShort) [fName]
+                (flagToGetOptArgDescr flagData)
+                (fDescription ++ " (default: " ++ fDefValue ++ ", from module: " ++ fModuleName ++ ")"))
 
       forceFlag FlagData { fName, fModuleName, fCheck } =
         fCheck `catch`
@@ -399,10 +435,8 @@
 
 -- | Has to be called from the main before doing anything else:
 --
--- @
--- main = do args <- $initHFlags "Simple program v0.1"
---           ...
--- @
+-- > main = do args <- $initHFlags "Simple program v0.1"
+-- >           ...
 --
 -- /Since version 0.2, you mustn't put the initHFlags in a parentheses with the program description.  Just/ @$initHFlags@, /it's cleaner./
 --
diff --git a/hflags.cabal b/hflags.cabal
--- a/hflags.cabal
+++ b/hflags.cabal
@@ -1,5 +1,5 @@
 name: hflags
-version: 0.2
+version: 0.3
 license: OtherLicense
 license-file: COPYING
 author: Mihaly Barasz <klao@google.com>, Gergely Risko <gergely@risko.hu>
@@ -22,8 +22,8 @@
   the toplevel @flags_name@ constants.  Those can be used purely
   throughout the program.
   .
-  At the beginning of the @main@ function, @$initHFlags "program
-  description"@ has to be called to initialize the flags.  All flags
+  At the beginning of the @main@ function, @$initHFlags \"program
+  description\"@ has to be called to initialize the flags.  All flags
   will be initialized that are transitively reachable via imports from
   @main@.  This means, that any Haskell package can easily define
   command line flags with @HFlags@.  This feature is demonstrated by
@@ -57,6 +57,12 @@
   long options and the user has to specify a value even for Bools.
   .
   /Since version 0.2, you mustn't put the initHFlags in a parentheses with the program description.  Just/ @$initHFlags@, /it's cleaner./
+  .
+  Changes in version 0.3
+  .
+  * Added @undefinedOptions@
+  .
+  * Added support for @Char@
   .
   Changes in version 0.2
   .