Use threadDelay instead of threadWaitRead to poll for notification on…

… windows since it seems to be a more robust approach.

src/Hasql/Notifications.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 {-|
  This module has functions to send commands LISTEN and NOTIFY to the database server.
  It also has a function to wait for and handle notifications on a database connection.
@@ -30,7 +31,11 @@ import qualified Data.Text.Encoding as T
 import Data.ByteString.Char8 (ByteString)
 import Data.Functor.Contravariant (contramap)
 import Control.Monad (void, forever)
+#if defined(mingw32_HOST_OS)
+import Control.Concurrent ( threadDelay )
+#else
 import Control.Concurrent (threadWaitRead)
+#endif
 import Control.Exception (Exception, throw)
 
 -- | A wrapped text that represents a properly escaped and quoted PostgreSQL identifier
@@ -160,8 +165,13 @@ waitForNotifications sendNotification con =
  mfd <- PQ.socket pqCon
  case mfd of
  Nothing -> panic "Error checking for PostgreSQL notifications"
+#if defined(mingw32_HOST_OS)
+ Just _ -> do
+ void $ threadDelay 1000000
+#else
  Just fd -> do
  void $ threadWaitRead fd
+#endif
  void $ PQ.consumeInput pqCon
  Just notification ->
  sendNotification (PQ.notifyRelname notification) (PQ.notifyExtra notification)