[Haskell-cafe] threadDelay delays less time than expected (Windows)

[amindfv at gmail.com]

(86400000000 :: Integer) > (fromIntegral (maxBound :: Int))

If True, your machine (32-bit?) is probably overflowing the Int

Tom


> El 28 dic 2016, a las 08:20, Lian Hung Hon <hon.lianhung at gmail.com> escribió:
> 
> Dear Haskellers,
> 
> I am baffled by a strange bug (?) with threadDelay on Windows. It delays for less time than expected (500 seconds vs expected 24 hours), and is consistently reproducible on my system. Can someone have a look (need some patience, ~8 minutes waiting), just to be sure? I glanced around trac but didn't find any related issues.
> 
> How to reproduce:
> 
> module Main where
> 
> import Data.Time
> import Control.Concurrent
> import Control.Monad
> 
> main :: IO ()
> main = do
>   _ <- forkIO thread
>   getLine >>= print  -- Just to keep the main thread running
> 
> thread :: IO ()
> thread = forever $ do
>   now <- getCurrentTime
>   print now
>   threadDelay 86400000000
>   print "done waiting"
> 
> 
> Expected result:
> 2016-12-28 13:07:49.5113098 UTC
> ...
> (next timing should be the next day 2016-12-29)
> 
> 
> Actual result:
> 2016-12-28 13:07:49.5113098 UTC
> "done waiting"
> 2016-12-28 13:16:10.2159485 UTC
> "done waiting"
> 2016-12-28 13:24:30.8735845 UTC
> "done waiting"
> 2016-12-28 13:32:51.5292203 UTC
> ...
> 
> 
> System: Windows 7 Enterprise Service Pack 1, ghc 7.10.3
> 
> 
> This seems specific to Windows, it doesn't appear on Debian 8. Help is appreciated!
> 
> 
> Regards,
> Hon
> 
> Rant: It has cost me significant debugging time! Please tell me I made a rookie mistake or misread the docs somewhere!
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