[Resending to the list] Thank you for your explanation. On Mon, Mar 4, 2013 at 10:32 PM, Simon Marlow wrote:

The issue is this: when the main thread exits, the RTS starts shutting down, and it kills all the other threads. If any of these threads were the result of an external in-call from C, then that call returns, with the status "Interrupted". Now, if this was a foreign export or a foreign import "wrapper", then there is no provision for returning an error code to the caller, so the foreign export must either

a) kill the current OS thread b) kill the whole process c) sleep indefinitely

Right now we do (b) I think. Perhaps (a) would be better; at least that might fix your problem.

Would it make sense to make rts behave differently depending on whether the process is going to be terminated? For example, could it do (c) when shutdownHaskellAndExit() is being called, and do (b) otherwise? - Akio