On 16 November 2005 17:38, Joel Reymont wrote:
I'm getting crashes like this and I cannot figure out what the problem is. I'm launching a bunch of threads that connect to a server via TCP and exchange packets.
I am running operations like connect and receive in a timeout function that launches two threads and uses an MVar to figure out who's done first. The timeout function then kills the two threads.
Any ideas what could be causing this? I feel like a Haskell guinea pig these days :-).
I don't see any reason why you should be getting crashes here, but this is a delicate area (async exceptions + FFI). It's possible there's a bug, but as usual we need to reproduce the symptoms here. Can you help with a repro case? Regarding the behaviour of killThread, I believe the version in GHC is slightly different from the version described in the Asynchronous Exceptions paper, in particular the GHC version blocks until the exception has been delivered to the target thread (use another forkIO to get the fully async version). Cheers, Simon