as i said in my other post (waiting for moderator approval), there are many people on this thread, and i'm not sure they are all talking about the same thing. perhaps a good step forward would be for each concrete proposal to go into a separate thread (beginning with a summary of the use pattern to be covered and the concrete extension proposal claiming to do the job), and then to see whether there is any consensus for any of them.
Well, my suggestion for one-shot routines would be to implement a simple Haskell library supporting named semaphores, and named channels. These resources need to be managed by the OS, so on unix the obvious way to implement them is to use unix-domain sockets for the channels, but their might be a more efficient way. oneTimeInit = do s <- testAndSetSemaphore "myUniqueString" if s then -- already run else -- not run yet Keean.