Re: [Chicken-users] How to FFI?

[felix winkelmann]

On 7/4/07, Robin Lee Powell <address@hidden> wrote:
> What's SWIG?

A heavy duty version of easyffi: http://www.swig.org

> I'm actually doing both CDK and libxmmsclient, and I don't need a
> compelet wrapper for either of them; I just want things to work, and
> I don't mind adding bits of CDK in as I need them.

So I'd recommend easyffi, or using normal FFI macros.

> As a related question, something I ran across in libxmmsclient that
> seems particularily tricky: a function with an int return value, but
> an int32_t *foo argument where the *actual* data is returned.
>
> In whichever method(s) you reccomend, how would I set up the 32-bit
> integer pointer, and then read data out of it after the call?

; manually:

(define foo (foreign-lambda int "foo" (c-pointer int)))

(let-location ((n int 0)) (my-function n) n)

or:

; easyffi:

#>?
int foo(___in int *x);
<#

(foo 123)


cheers,
felix