Posix library ,Concurrent Haskell and Haskell IO sub-system

[Volker Stolz]

On Fri, Jul 11, 2003 at 07:37:06AM +0200, Rafael Martinez Torres wrote:
> > Why do you "have to" use an Fd?
> >A regular handle should be sufficient.
> > Where do you get the Fd from?
> 
> createPipe :: IO (Fd,Fd) (Unkown alternatives)

I suppose you have to pass this descriptor to another process
through fork()?

> > Did you consider lifting the Fd back
> > to a Handle?
> 
> How ? Only known
> intToFd :: Int -> Fd
> fdToInt :: Fd -> Int

There's System.Posix.IO.fdToHandle :: Fd -> IO Handle

> What about ?
> threadReadWait :: Int -> IO()
> Should I convert a Handle into a Int ?

Yes, that should work, too, but you won't know how many bytes are available.
You could use or adapt one of the *MayBlock-ellipses from Foreign.C.Error
together with threadWaitRead, but that's making things even more ugly.

Volker
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