Some experiment with System.Posix.Signals in Haskell

Main.hs

module Main where
import System.Posix
import System.Posix.IO
import System.Posix.Signals

test childRead fatherWrite = do
  (r, _) <- fdRead childRead 10
  putStrLn r 

childHandler = do
  putStrLn "call"
  raiseSignal sigKILL

fatherLoop fdr fdw = do
  installHandler sigCHLD (CatchOnce childHandler) Nothing
  putStrLn "fatherLoop"
  fdWrite fdw "test"
  fdWrite fdw "exit"
  fatherLoop fdr fdw

childLoop fdr fdw = do
  putStrLn "childLoop"
  (r, c) <- fdRead fdr 4
  case r of
    "exit" -> putStrLn "done" >> raiseSignal sigCHLD
    otherwise -> putStrLn r >> childLoop fdr fdw

main :: IO ()
main = do
  putStrLn "Hello, Haskell!"
  (fatherRead, fatherWrite) <- createPipe
  (childRead, childWrite) <- createPipe
  x <- forkProcess $ childLoop childRead fatherWrite
  fatherLoop fatherRead childWrite
  putStrLn "stop"