Hi Christoph,
I think that NULL should be correct and work - since you're creating a pointer object to address 0. However, the FFI has a convenience for null-pointers: you can pass in #f instead. That's easier and requires one less GC object. It's mentioned in the manual on c-pointer foreign type:
http://wiki.call-cc.org/man/5/Foreign%20type%20specifiers#pointers
That takes me to my personal experience which I want to share: when creating foreign bindings, just use foriegn-lambda and skip the bind dependency. Maybe when you have huge API's, bind can save you some time. But I'd say that hand-written foreign-lambdas give you more control of what's going on, force you to think about every function and make sure it's safe and generally produce better interfaces.
I hope this may give you some pointers.
K.
I wrote the following in my attempt to interface to the mosquitto MQTT library:
(bind* "struct mosquitto *mosquitto_new(const char *id,
(define NULL (object->pointer 0))
(define mqttc (mosquitto-new NULL #t NULL))
But I'm unsure about my adventurous definition of `NULL`. It works, but is it correct?
Another thing: on the bind egg's documentation page, `___blob` is not mentioned, but I luckily found it in the sql-de-lite code, and it saved me a lot of headaches :-) Shouldn't it be there?
/Christoph
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