X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=Control%2FConcurrent%2FQSemN.hs;h=cfcff7f5d8c4e89794a6a4475073afffc1237782;hb=41e8fba828acbae1751628af50849f5352b27873;hp=df3fa4207b754958c8d523f71a4e66beeb2ef10f;hpb=3d4f3f4b8bc5571d3015816671457c88c0e697c3;p=ghc-base.git

diff --git a/Control/Concurrent/QSemN.hs b/Control/Concurrent/QSemN.hs
index df3fa42..cfcff7f 100644
--- a/Control/Concurrent/QSemN.hs
+++ b/Control/Concurrent/QSemN.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE CPP #-}
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Control.Concurrent.QSemN
@@ -24,14 +26,14 @@ module Control.Concurrent.QSemN
 import Prelude
 
 import Control.Concurrent.MVar
-import Control.Exception ( block )
+import Control.Exception ( mask_ )
 import Data.Typeable
 
 #include "Typeable.h"
 
 -- |A 'QSemN' is a quantity semaphore, in which the available
 -- \"quantity\" may be signalled or waited for in arbitrary amounts.
-newtype QSemN = QSemN (MVar (Int,[(Int,MVar ())]))
+newtype QSemN = QSemN (MVar (Int,[(Int,MVar ())])) deriving Eq
 
 INSTANCE_TYPEABLE0(QSemN,qSemNTc,"QSemN")
 
@@ -46,7 +48,7 @@ newQSemN initial =
 
 -- |Wait for the specified quantity to become available
 waitQSemN :: QSemN -> Int -> IO ()
-waitQSemN (QSemN sem) sz = block $ do
+waitQSemN (QSemN sem) sz = mask_ $ do
   (avail,blocked) <- takeMVar sem   -- gain ex. access
   let remaining = avail - sz
   if remaining >= 0 then
@@ -60,7 +62,7 @@ waitQSemN (QSemN sem) sz = block $ do
 
 -- |Signal that a given quantity is now available from the 'QSemN'.
 signalQSemN :: QSemN -> Int  -> IO ()
-signalQSemN (QSemN sem) n = block $ do
+signalQSemN (QSemN sem) n = mask_ $ do
    (avail,blocked)   <- takeMVar sem
    (avail',blocked') <- free (avail+n) blocked
    avail' `seq` putMVar sem (avail',blocked')