Network, sClose

Glynn Clements glynn.clements at
Fri Aug 13 16:53:42 EDT 2004

Simon Marlow wrote:

> > OTOH, the core problem with Network.recvFrom is essentially that it
> > appears to be a misguided attempt to provide a symmetric counterpart
> > to Network.sendTo. While the low-level sendTo/recvFrom functions may
> > be roughly symmetric, at a higher level, the client and server ends of
> > a connection aren't at all symmetric.
> Yes, I'm sure that's the reason for it.  Proposals for a replacement are
> welcome...

What would be the intended purpose of a replacement?

If you want a simpler interface for writing servers, it would probably
look something like:

	doServer :: PortID -> (Handle -> IO ()) -> IO ()
	doServer port handler = do
		s <- listenOn port
		let doIt = do
			~(s', _)  <-  Socket.accept s
			h <- socketToHandle s' ReadWriteMode
			forkIO $ handler h >> hClose h
		sequence_ $ repeat doIt

Ultimately, you either need to create a separate thread/process per
connection, or manually service multiple connections (select/poll). A
server which processed connections sequentially wouldn't be of much
practical use (and a one-shot server probably wouldn't even be of use
for "toy" programs).

Glynn Clements <glynn.clements at>

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