Hi Patrick,

On Fri, Sep 10, 2010 at 2:02 PM, Patrick LeBoutillier <patrick.leboutillier@gmail.com> wrote:

In order to get better at network programming using haskell, I'd like
to try and port it to Haskell, but I can't seem to locate the
equivalent to select(2) in Haskell. Perhaps a different idiom is to be
used?

GHC uses select/epoll/kqueue internally to multiplex its lightweight threads. When you would use a select loop for handle many connections in one language you would typically launch one thread per connection in Haskell, using forkIO. With the upcoming version GHC can handle 100k+ threads this way. Right now the limit is 1024 simultaneous connections due a hard coded limit in select.

You code would look something like this:

acceptConnections serverSock = do
    sock <- accept severSock
    forkIO $ handleConnection sock
    acceptConnections serverSock

handleConnection sock = do
    msg <- recv
    send ...
    sClose sock

I'd recommend using the network-bytestring library which provides more efficient versions of e.g. recv and send.

Cheers,
Johan