blob: 68c2a871b8e4cce169aab5bc9c901583775d002c (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
|
import System.Random
import Control.Concurrent.SampleVar
import Control.Concurrent
import Control.Monad
produce, consume :: SampleVar Int -> IO ()
produce svar = do
b <- isEmptySampleVar svar
if b then writeSampleVar svar 3 else return ()
consume svar = readSampleVar svar >>= print
main = do
svar <- newEmptySampleVar
m <- newEmptyMVar
forkIO $ consume svar >> putMVar m ()
threadDelay 100000 -- 100 ms
produce svar
takeMVar m -- deadlocked before the fix in #4876
|
