11 Jul
2013
11 Jul
'13
12:13 a.m.
+1 for changing readMVar to be atomic, but we should probably mention the change in the doc for readMVar, something like the following (perhaps in fewer words): -- | ... -- -- /Compatibility note:/ prior to base 4.7, 'readMVar' was a combination -- of 'takeMVar' and 'putMVar', resulting in two drawbacks: -- -- * 'readMVar' was not atomic in the presence of multiple producers. -- Between taking the value and putting it back, another thread -- calling 'putMVar' could win, causing 'readMVar' to block after -- retrieving a value. -- -- * 'readMVar' was not multiple wakeup, meaning each consumer had to -- wake up the next.