Re: [Haskell-cafe] Cleaning up threads

Also don't forget to unblock asynchronous exceptions inside 'someWorkToDo' otherwise you can't throw exceptions to the thread. Note that 'finally' unblocks asynchronous exceptions but I consider this a bug. In the upcoming base library this is fixed[1] but I would advise to fix the code right now to not be surprised later. Also note that the threads library correctly unblocks asynchronous exceptions when necessary. Regards, Bas [1] http://hackage.haskell.org/trac/ghc/ticket/4035 On Wed, Sep 15, 2010 at 7:38 AM, Gregory Collins wrote:

Bas van Dijk writes:

...

Don't forget to block asynchronous exception _before_ you fork in:

...

       tid <- forkIO (someWorkToDo `finally` putMVar mv ())

Otherwise an asynchronous exception might be thrown to the thread _before_ the 'putMVar mv ()' exception handler is installed leaving your main thread in a dead-lock!

Good catch, thank you,

G -- Gregory Collins