Quoth Bas van Dijk
I understand why it's problematic to fork a process which is in the middle of running multiple simultaneous threads. However, in the case of a daemon the fork happens in the beginning of the program. So if I can manage to create a program that first daemonizes my process then starts the Haskell program, all is good.
type ProcessID = CInt type Fd = CInt foreign import ccall "fork" c_fork :: IO CInt foreign import ccall "_exit" _exit :: CInt -> IO () fork :: IO Int -> IO ProcessID fork fn = do pid <- c_fork if pid == 0 then do fn >>= _exit . fromIntegral return 0 -- unused, I reckon else if pid > 0 then return pid else throwErrno "fork" System.PosixProcess (exitImmediately) is supposed to be "_exit". I would not care to hazard a guess as to whether this will work reliably for you. If you figure out how to use your own custom C main() function, I'd be interested to know. I use separate C programs that exec my Haskell programs. My current GHC can't compile -via-C, but if you can compile a minimal "main" module to C that way, it probably calls hs_main() or something like that? and you could add your own xx_main() to the stack. Donn Cave, donn@avvanta.com