I am still reading the web pages. Here is what I tried:

data SigNotify = Signal | None | Thread | ThreadId

instance Storable SigNotify where

   sizeOf _ = (#const sizeof (int))

   alignment _ = 1

   poke Signal = (#const SIGEV_SIGNAL)

   poke None = poke (#const SIGEV_NONE)

   poke Thread = poke (#const SIGEV_THREAD)

   poke ThreadId = poke (#const SIGEV_THREAD_ID)

but I got ...

    Couldn't match expected type `Ptr SigNotify'
           against inferred type `SigNotify'
    In the pattern: Signal
    In the definition of `poke': poke Signal = poke (0)
    In the definition for method `poke'

Basically I want to marshall SigInfo constructors to CInt values. ??

Regards, Vasili

On Fri, Jun 20, 2008 at 3:20 PM, Bulat Ziganshin <bulat.ziganshin@gmail.com> wrote:

Hello Vasili,

Friday, June 20, 2008, 11:51:11 PM, you wrote:
> data Bonzo = A | B |C

> How do I write the poke functions and call them?

instance Storable Bonzo
poke A = poke 0
poke B = poke 1
poke C = poke 4

call as "poke x"

probably, you don't understand differences between OOP classes and
type classes. look at http://haskell.org/haskellwiki/OOP_vs_type_classes
and papers mentioned there

--
Best regards,
Bulat mailto:Bulat.Ziganshin@gmail.com