I would like my Haskell program to exitFailure when the program is interrupted, so I changed the handler function to this:

import System.Exit (exitFailure)

…

handler :: MVar Int -> IO () handler mi = do i <- takeMVar mi putStrLn “In handler” exitFailure

But when I run this code, the program doesn’t actually exit. It just prints out a notice that main.hs raised exitWith (Failure 1).