Question

Is there something like System.Posix on windows?

I want the code below to run on windows, should I change it?

import IO
import Control.Exception hiding (catch)
import Control.Concurrent
import Network
import System.Posix   ---cannot be run on windows.

main = withSocketsDo (installHandler sigPIPE Ignore Nothing >> main')
    --so the signal handler cannot be used

main' = listenOn (PortNumber 9900) >>= acceptConnections

acceptConnections sock = do
        putStrLn "trying to accept" -- debug msg
        conn@(h,host,port) <- accept sock
        print conn -- debug msg
        forkIO $ catch (talk conn `finally` hClose h) (\e -> print e)
        acceptConnections sock

talk conn@(h,_,_) = hGetLine h >>= hPutStrLn h >> hFlush h >> talk conn

for example ,if I want the program to quit when ctrl+c,I must add a handler for SIGINT ,so in c++,write some code like this:

void callback(int sig) 
{ 
   // printf("catch\n"); 
} 
... 
signal(SIGINT,callback); 

But I don’t know how to do this in haskell,use FFI?

Answer 1

import Foreign
import Foreign.C.Types

type Handler = CInt->IO ()
foreign import ccall "wrapper"
  genHandler:: (Handler) -> IO (FunPtr Handler)

foreign import ccall safe "signal.h signal"
        install:: CInt->FunPtr Handler->IO CInt
main=do
        s<-genHandler (\x->putStrLn $ "catch "++(show x))
        res<- install 2 s
        putStrLn $ show res
        s<-getLine

the code above is what i wanna do,just import the signal function,with a haskell callback.