Re: [Sbcl-help] How to pass bignums to foreign routines?

[Christophe R. <cs...@ca...>]

Waldek Hebisch <he...@ma...> writes:

> I tried:
>
> (defun ttt (x)
>   (sb-sys:with-pinned-objects (x)                         
>     (SB-ALIEN::alien-funcall
>        (SB-ALIEN::extern-alien "ppp"
>            (SB-ALIEN::function SB-ALIEN::void t))    
>        x)))

Try

(defun ttt (x)
  (sb-sys:with-pinned-objects (x)
    (let* ((addr (sb-kernel:get-lisp-obj-address x))
           (sap (sb-sys:int-sap addr)))
      (sb-alien:alien-funcall
        (sb-alien:extern-alien "ppp" (sb-alien:function sb-alien:void (* t)))
        sap))))

The pointer that the C side will receive will still have its lisp tag
on.

Cheers,

Christophe