fdReady cannot wait more than 49 days

import System.IO
hWaitForInput stdin 4294968296

This code waits for 1 second instead of 49.something days.

The culprit:

hWaitForInput :: Handle -> Int -> IO Bool
fdReady(..., int msecs, ...)

Haskell Int is usally 64 bits. C int is usually 32 bits.

Called here:

ready :: FD -> Bool -> Int -> IO Bool
ready fd write msecs = do
  r <- throwErrnoIfMinus1Retry "GHC.IO.FD.ready" $
          fdReady (fdFD fd) (fromIntegral $ fromEnum $ write)
                            (fromIntegral msecs)

foreign import ccall safe "fdReady"
  fdReady :: CInt -> CInt -> CInt -> CInt -> IO CInt

We fromIntegral Int to CInt (== Int32), overflowing.