lock_rts.hs

import Control.Concurrent
import Control.Exception
import Control.Monad
import Network.Socket

main = forever $ do
  pair <- try $ socketPair AF_UNIX Stream defaultProtocol
  case pair of 
       Left e -> do
         let _ = e :: SomeException
         putStrLn "sleep"
       Right (sClient, sServer) -> do
         putStrLn "open"
         forkIO $ client sClient
         forkIO $ server sServer
         forkIO $ killer sServer sClient
         return ()

bufLen = 5
buf = "hello"

client sock = forever $ do
  send sock buf
  _ <- recv sock bufLen
  return ()
  
server sock = forever $ do
  buf <- recv sock bufLen
  send sock buf

killer s1 s2 = do
  putStrLn "close"
  sClose s1
  sClose s2