Re: [Chicken-users] Constructing parameter lists in C: can I use FFI?

[felix winkelmann]

On 7/25/05, felix winkelmann <address@hidden> wrote:
> 
> ;;;; x.scm:
> 
> (define-external (foo (int x) (c-string y)) double
>   (print (list x y))
>   (sqrt x) )
> 
> (##sys#call-host)
> 
> /* y.c */
> 
> #include "chicken.h"
> 
> extern double foo(int, char*);
> 
> int main()
> {
>   CHICKEN_run(NULL, NULL, NULL, C_toplevel);
>   C_restore; /* <- pop continuation, unless we call an entry-point
> this should be ok, */
>   printf("-> %g\n", foo(42, "abc"));
>   printf("-> %g\n", foo(32, "abc"));
>   return 0;
> }
> 

Here the same example with callbacks (from C to Scheme to C and into Scheme
again):


;;;; x.scm

#>!
___safe double cb1(int x, char *y) { foo(x, y); }
<#

(define-external (foo (int x) (c-string y)) double
 (print (list x y))
 (sqrt x) )

(define-external (bar (int x) (c-string y)) double
 (print "bar: " (list x y))
 (cb1 x y) )

(##sys#call-host)

/* y.c */

#include "chicken.h"

extern double foo(int, char*);

int main()
{
 CHICKEN_run(NULL, NULL, NULL, C_toplevel);
 C_restore; /* <- pop continuation, unless we call an entry-point this
should be ok, */
 printf("-> %g\n", foo(42, "abc"));
 printf("-> %g\n", bar(32, "def"));
 printf("-> %g\n", foo(2, "xyz"));
 return 0;
}


cheers,
felix