From: Justin Collins <justincollins@...>
Date: 2009-10-29T04:57:40+09:00
Subject: Re: FFI and pointers

Thorsten Hater wrote:
> Hello,
>
> I'm playing around with FFI and encountered a problem, I could not solve
> till now.
> Let's assume I use standard C's malloc in my wrapper:
>
> attach_function :malloc, [:int], :pointer
>
> so far no problem. But what now? The pointer returned is of type void*,
> which is of no help, since I need double*, int*  and float*  ...
> Is there a type cast mechanism in FFI (or anything similar) or do I 
> have to wrap
> the original library in another layer of C (alternatively write a 
> helper lib...)
> Or can I import C's typecasts using FFI itself?
>
> Best regards,
>     Thorsten
>
>

If nothing else, you can use the read_* and write_* methods (like 
read_int) to interact with it.

-Justin