On 04/03/13 06:02, Akio Takano wrote:
Hi,
If I compile and run the attached program in the following way, it crashes on exit:
$ ghc -threaded thr_interrupted.hs $ ./thr_interrupted thr_interrupted: Main_dtl: interrupted
This is particularly bad when profiling, because the program terminates before writing to the .prof file.
Is this a bug in GHC, or am I supposed to terminate the thread before exiting? If it's a GHC issue, how should it be fixed? It seems that the error was raised in the C stub code GHC generated for the foreign import "wrapper" function.
So this behaviour is "by design", that is, I intended it to work this way. That's not to say it's necessarily the best design; maybe a better alternative exists. 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. Cheers, Simon