Allow disabling signal support in configure.

src/GF/System/Signal.hs

@@ -1,3 +1,5 @@
+{-# OPTIONS -cpp #-}
+
 ----------------------------------------------------------------------
 -- |
 -- Module      : GF.System.Signal
@@ -5,44 +7,21 @@
 -- Stability   : (stability)
 -- Portability : (portability)
 --
--- > CVS $Date: 2005/11/07 22:27:13 $ 
+-- > CVS $Date: 2005/11/11 11:12:50 $ 
 -- > CVS $Author: bringert $
--- > CVS $Revision: 1.2 $
+-- > CVS $Revision: 1.3 $
 --
--- Allows SIGINT (Ctrl-C) to interrupt computations.
+-- Import the right singal handling module.
 -----------------------------------------------------------------------------
 
-module GF.System.Signal where
+module GF.System.Signal (runInterruptibly) where
 
-import Control.Concurrent (myThreadId, killThread)
-import Control.Exception (Exception,catch)
-import Prelude hiding (catch)
-import System.IO
-import System.Posix.Signals
+#ifdef USE_INTERRUPT
 
--- | Run an IO action, and allow it to be interrupted
---   by a SIGINT to the current process. Returns
---   an exception if the process did not complete 
---   normally.
---   NOTES: 
---   * This will replace any existing SIGINT
---     handler during the action. After the computation 
---     has completed the existing handler will be restored.
---   * If the IO action is lazy (e.g. using readFile,
---     unsafeInterleaveIO etc.) the lazy computation will
---     not be interruptible, as it will be performed
---     after the signal handler has been removed.
-runInterruptibly :: IO a -> IO (Either Exception a)
-runInterruptibly a = 
-    do t <- myThreadId
-       oldH <- installHandler sigINT (Catch (killThread t)) Nothing
-       x <- p `catch` h
-       installHandler sigINT oldH Nothing
-       return x
-  where p = a >>= \x -> return $! Right $! x
-        h e = return $ Left e
+import GF.System.UseSignal (runInterruptibly)
 
--- | Like 'runInterruptibly', but always returns (), whether
---   the computation fails or not.
-runInterruptibly_ :: IO () -> IO ()
-runInterruptibly_ = fmap (either (const ()) id) . runInterruptibly
+#else
+
+import GF.System.NoSignal (runInterruptibly)
+
+#endif