Socket related IO cannot be be interrupted on Windows

[igloo]

Originally reported here: http://hackage.haskell.org/trac/ghc/ticket/2943

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While playing with socket communication, I noticed that socket IO cannot be interrupted or killed. The attached program simply hangs, irregardless whether is was complied using the -threaded flag or not.

import Network
import Control.Concurrent

main = withSocketsDo $ do
    tid <- forkIO $ do
        s <- listenOn (PortNumber 1234)
        accept s
        return ()
    threadDelay 2000000
    killThread tid

[simonmar]

This is because accept makes a safe FFI call on Windows, whereas on Unix it uses threadWaitRead to wait for a connection (threadWaitRead is interruptible, but not available on Windows).

It looks to me like it ought to be interruptible without -threaded, I don't completely understand what's going on there.

Ideally we would have an IO manager thread on Windows and handle this in the same way as other blocking IO operations, but that's a big job.

[simonmar]

oops, didn't mean to assign ownership.