[cffi-devel] Re: [feature request] array type

[Luís Oliveira]

On 2005-dec-11, at 06:48, Jack Unrue wrote:
> My goal is simply to declare structs whose C equivalent includes
> array members. I'm not sure how the array declaration would
> be done in CFFI so I'll use LispWorks FLI instead:
>
> (fli:define-c-struct foo
>     (data (:c-array :int 32))
>     (id :int))

This would translate to:

   (cffi:defcstruct foo
     (data :int :count 32)
     (id :int))

The plan is that you would access an element of this array using
(cffi:foreign-slot-value foo-obj 'foo 'data <index>). However,
this is not implemented yet so, for the time being, you'll need
to use something like:

   (cffi:mem-aref (cffi:foreign-slot-value foo-obj 'foo 'data)
                  :int <index>)

Or:

   (cffi:with-foreign-slots ((data) foo-obj foo)
     (cffi:mem-aref data :int <index>))


This is not to say that an array type is not needed. I think
we'll need one in order to access multi-dimensional arrays
conveniently.

-- 
Luís Oliveira
http://student.dei.uc.pt/~lmoliv/
Equipa Portuguesa do Translation Project
http://www.iro.umontreal.ca/translation/registry.cgi?team=pt