[Haskell-cafe] advancePtr for ForeignPtr

[Henning Thielemann]

On Mon, 23 Feb 2009, Felipe Lessa wrote:

> On Mon, Feb 23, 2009 at 10:12 AM, Henning Thielemann
> <lemming at henning-thielemann.de> wrote:
>> Is still someone on haskell.org ?
>
> Sorry, I don't know :).

I meant ffi at haskell.org

>> Do I have to use 'touchForeignPtr' as finalizer of the subarray's ForeignPtr
>> in order to assert that the superarray lives at least as long as the
>> subarray?
>
> This may work, but seems like a fragile hack. Why not
>
>
>  data SubArray a = SA {-# UNPACK #-} !(ForeignPtr a)
>                       {-# UNPACK #-} !Int

This would work, but I want to convert from StorableVector to CArray and 
StorableVector has an offset parameter, which is missing in CArray.