Try something like this:
module Main where
import Network.Socket
main = withSocketsDo $ do
-- Make a UDP socket
s <- socket AF_INET Datagram defaultProtocol
-- We want to listen on all interfaces (0.0.0.0)
bindAddr <- inet_addr "0.0.0.0"
-- Bind to 0.0.0.0:30000
bindSocket s (SockAddrInet 30000 bindAddr)
-- Read a message of max length 1000 from some one
(msg,len,from) <- recvFrom s 1000
putStrLn $ "Got the following message from " ++ (show from)
putStrLn msg
Does this help? As Stephan said, you missed the bind step.
/jve
On Sun, Jan 25, 2009 at 11:22 AM, Andrew Coppin wrote: I'm trying to write a simple program that involves UDP. I was hoping
something like this would work: module Main where import Network.Socket main = withSocketsDo main2 main2 = do
s <- socket AF_INET Datagram defaultProtocol
putStrLn "Waiting..."
x <- recv s 100
putStrLn x Unfortunately, that doesn't work at all. It immediately throws an exception
("unknown error"). But then, the whole module seems to be completely
undocumented. I managed to find a tiny amount of info online about the
underlying C API, but I still don't get how the Haskell interface is
supposed to be used. Any hints? _______________________________________________
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