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    <p><em>Control-C handling does not work with <code>catch</code></em>: may be related to <a href="http://hackage.haskell.org/trac/ghc/ticket/2301">GHC #2301: Proper handling of SIGINT/SIGQUIT</a></p> <p>Here is a working testcase, with the <code>evaluator</code> removed:</p> <pre><code>module Main where import Prelude hiding (catch) import Control.Exception ( SomeException(..), AsyncException(..) , catch, handle, throw) import Control.Monad (forever) import System.IO repl :: IO () repl = forever $ (do putStr "&gt;&gt;&gt; " &gt;&gt; hFlush stdout out &lt;- getLine if null out then return () else putStrLn out) `catch` onUserInterrupt onUserInterrupt UserInterrupt = putStrLn "\nUserInterruption" onUserInterrupt e = throw e main = do handle onAbort repl putStrLn "Exiting..." onAbort e = do let x = show (e :: SomeException) putStrLn $ "\nAborted: " ++ x </code></pre> <p>On Linux, Control-Z is not caught as Sjoerd mentioned. Perhaps you are on Windows, where Control-Z is used for EOF. We can signal EOF on Linux with Control-D, which replicates the behavior you saw:</p> <pre><code>&gt;&gt;&gt; ^D Aborted: &lt;stdin&gt;: hGetLine: end of file Exiting... </code></pre> <p>EOF is handled by your <code>handle/onAbort</code> function, and Control-C is handled by <code>catch/onUserInterrupt</code>. The issue here is that your <code>repl</code> function will only catch the first Control-C -- the testcase can be simplified by removing the <code>handle/onAbort</code> function. As noted above, that Control-C handling does not work with <code>catch</code> may be related to <a href="http://hackage.haskell.org/trac/ghc/ticket/2301">GHC #2301: Proper handling of SIGINT/SIGQUIT</a>.</p> <p>The following version instead uses the Posix API to install a persistent signal handler for Control-C:</p> <pre><code>module Main where import Prelude hiding (catch) import Control.Exception ( SomeException(..), AsyncException(..) , catch, handle, throw) import Control.Monad (forever) import System.IO import System.Posix.Signals repl :: IO () repl = forever $ do putStr "&gt;&gt;&gt; " &gt;&gt; hFlush stdout out &lt;- getLine if null out then return () else putStrLn out reportSignal :: IO () reportSignal = putStrLn "\nkeyboardSignal" main = do _ &lt;- installHandler keyboardSignal (Catch reportSignal) Nothing handle onAbort repl putStrLn "Exiting..." onAbort e = do let x = show (e :: SomeException) putStrLn $ "\nAborted: " ++ x </code></pre> <p>which can handle Control-Cs being pressed multiple times:</p> <pre><code>&gt;&gt;&gt; ^C keyboardSignal &gt;&gt;&gt; ^C keyboardSignal &gt;&gt;&gt; ^C keyboardSignal </code></pre> <p>If not using the Posix API, installing a persistent signal handler on Windows requires re-raising the exception each time it is caught, as described in <a href="http://suacommunity.com/dictionary/signals.php">http://suacommunity.com/dictionary/signals.php</a></p>
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