X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=Control%2FConcurrent%2FSampleVar.hs;h=ca68a38f76714e7d9d1761411ff68c7e9df4123f;hb=41e8fba828acbae1751628af50849f5352b27873;hp=c66241e2564e2c897b854f13fef39d7124414f7a;hpb=4c29f6f110d23b890567b8696a964bb212eba52e;p=ghc-base.git

diff --git a/Control/Concurrent/SampleVar.hs b/Control/Concurrent/SampleVar.hs
index c66241e..ca68a38 100644
--- a/Control/Concurrent/SampleVar.hs
+++ b/Control/Concurrent/SampleVar.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE CPP #-}
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Control.Concurrent.SampleVar
@@ -34,6 +36,10 @@ import Control.Exception ( mask_ )
 
 import Data.Functor ( (<$>) )
 
+import Data.Typeable
+
+#include "Typeable.h"
+
 -- |
 -- Sample variables are slightly different from a normal 'MVar':
 -- 
@@ -58,6 +64,8 @@ newtype SampleVar a = SampleVar ( MVar ( Int    -- 1  == full
                                 )
     deriving (Eq)
 
+INSTANCE_TYPEABLE1(SampleVar,sampleVarTc,"SampleVar")
+
 -- |Build a new, empty, 'SampleVar'
 newEmptySampleVar :: IO (SampleVar a)
 newEmptySampleVar = do
@@ -120,5 +128,5 @@ writeSampleVar (SampleVar svar) v = mask_ $ do
 isEmptySampleVar :: SampleVar a -> IO Bool
 isEmptySampleVar (SampleVar svar) = do
    (readers, _) <- readMVar svar
-   return (readers == 0)
+   return (readers <= 0)