On Mon, 30 Jul 2007, Duncan Coutts wrote: ...
You generally do not want forkOS. It's really only for wierd foreign libs that require that they be called from the same OS thread every time eg because they keep thread local state (like OpenGL).
Can Haskell application code run in a thread created by the foreign library? I'm assuming some requirement for C level API to bootstrap the new thread in the runtime. ...
In both ghc only uses on OS thread for IO. In the threaded rts it's an *additional* OS thread but it's still only one.
In the single threaded rts, it's the rts that does the select/poll. In the threaded rts it's a Haskell IO manager thread that uses select/poll on behalf of other Haskell threads that need to block until the completion of I/O.
Can my own application's foreign I/O plug into that IO manager? Does select work for all I/O? For example, take DNS - Network.BSD.getHostByName could involve some network I/O and a lengthy delay, but as far as I know there isn't any select-friendly interface even at the lower levels. Or System.Posix.getProcessStatus, which doesn't generate any I/O in the sense of a selectable device. Donn Cave, donn@drizzle.com