Re: type friction C <-> scheme

[Matt Wette]

> On Jun 9, 2017, at 1:36 PM, Catonano <address@hidden> wrote:
> 
> Here we go again
> 
> After successfully wrapping freexl_open, I can't do the same with
> freexl_get_info
> 
> One of the arguments expected by such function is "unsigned short"
> 
> When I load the namespace at the REPL I get
> 
> scheme@(guile-user)> ,m (freexl common)
> While executing meta-command:
> ERROR: In procedure pointer->procedure: Wrong type argument in position 3:
> int
> 
> I tried with uint8, uint16 and uint32, with the same result
> 
> Here's the function I'm referring to
> 
> https://www.gaia-gis.it/gaia-sins/freexl-1.0.1-doxy-doc/html/freexl_8h.html#ad6dbe072c7a4632853d90f4509bf3aee
> 
> And here's my code (there are some instructions as comments in the code)
> https://gitlab.com/humanitiesNerd/guile-freexl
> 
> And here's an excerpt
> 
> (define freexl-get-info
>  (let* ((ptr     (freexl-func "freexl_get_info"))
>         (proc    (pointer->procedure int ptr '(* int *)))
>     ;;the int in the arguments list generates
>     ;;a wrong argument type error when
>     ;;loading the namespace at the REPL, like this
>     ;;scheme@(guile-user)> ,m (freexl common)
>     ;;While executing meta-command:
>     ;;ERROR: In procedure pointer->procedure: Wrong type argument
>     ;;in position 3: int
> 
>     )
>    (lambda (handle-ptr what)
>      (let* ((outcome-ptr (bytevector->pointer (make-bytevector (sizeof
> '*))))
>         (result (proc handle-ptr what outcome-ptr)))
>    (if (not (= result 0))
>        (throw 'get-info-error 'error-code result)
>        outcome-ptr)
>    ))))
> 
> Thanks in advance

I think your outcome-ptr should be (bytevector->pointer (make-bytevector 
(sizeof unsigned-int)))