X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=Debug%2FTrace.hs;h=ebacb6c3d7fa28d37e385a2d240c97b2bd4d8d78;hb=be2750a0a11b919fb03cc070074e430f88bdfa90;hp=16a614e6614a3e729c6229ae57929c400c925394;hpb=e8a5a9136fee6d032580b885457581955884a777;p=ghc-base.git

diff --git a/Debug/Trace.hs b/Debug/Trace.hs
index 16a614e..ebacb6c 100644
--- a/Debug/Trace.hs
+++ b/Debug/Trace.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE CPP, ForeignFunctionInterface #-}
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Debug.Trace
@@ -13,9 +15,9 @@
 -----------------------------------------------------------------------------
 
 module Debug.Trace (
-	-- * Tracing
-	putTraceMsg,      -- :: String -> IO ()
-	trace,            -- :: String -> a -> a
+        -- * Tracing
+        putTraceMsg,      -- :: String -> IO ()
+        trace,            -- :: String -> a -> a
         traceShow
   ) where
 
@@ -41,7 +43,9 @@ putTraceMsg msg = do
      withCString msg  $ \cmsg ->
       debugBelch cfmt cmsg
 
-foreign import ccall unsafe "RtsMessages.h debugBelch"
+-- don't use debugBelch() directly, because we cannot call varargs functions
+-- using the FFI.
+foreign import ccall unsafe "HsBase.h debugBelch2"
    debugBelch :: CString -> CString -> IO ()
 #endif