Use explicit language extensions & remove extension fields from base.cabal

[ghc-base.git] / Control / Concurrent / QSem.hs

diff --git a/Control/Concurrent/QSem.hs b/Control/Concurrent/QSem.hs
index c009aaf..22f6c0c 100644 (file)
--- a/Control/Concurrent/QSem.hs
+++ b/Control/Concurrent/QSem.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE CPP #-}
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Control.Concurrent.QSem
@@ -22,7 +24,7 @@ module Control.Concurrent.QSem
 
 import Prelude
 import Control.Concurrent.MVar
-import Control.Exception ( block )
+import Control.Exception ( mask_ )
 import Data.Typeable
 
 #include "Typeable.h"
@@ -36,7 +38,7 @@ import Data.Typeable
 
 -- |A 'QSem' is a simple quantity semaphore, in which the available
 -- \"quantity\" is always dealt with in units of one.
-newtype QSem = QSem (MVar (Int, [MVar ()]))
+newtype QSem = QSem (MVar (Int, [MVar ()])) deriving Eq
 
 INSTANCE_TYPEABLE0(QSem,qSemTc,"QSem")
 
@@ -51,7 +53,7 @@ newQSem initial =
 
 -- |Wait for a unit to become available
 waitQSem :: QSem -> IO ()
-waitQSem (QSem sem) = block $ do
+waitQSem (QSem sem) = mask_ $ do
    (avail,blocked) <- takeMVar sem  -- gain ex. access
    if avail > 0 then
      let avail' = avail-1
@@ -72,7 +74,7 @@ waitQSem (QSem sem) = block $ do
 
 -- |Signal that a unit of the 'QSem' is available
 signalQSem :: QSem -> IO ()
-signalQSem (QSem sem) = block $ do
+signalQSem (QSem sem) = mask_ $ do
    (avail,blocked) <- takeMVar sem
    case blocked of
      [] -> let avail' = avail+1