Re: [gambit-list] check vs null

On 14-Feb-09, at 5:32 PM, lowly coder wrote:

it works now; thanks!

the main reason I posted to gambit rather than #scheme ... is that this seems a C-FFI (thus implementation specific question, not a generic scheme question)

if I'm wrong ... please point out what scheme standard defines how NULLS from C-FFI/land is handled in scheme?

If you define get-foo this way

(define get-foo (c-lambda () (pointer foo) "get_foo"))

then the C NULL maps to the Scheme #f. On the other hand, if you want to exclude the possibility that the pointer is NULL then define it this way

(define get-foo (c-lambda () (nonnull-pointer foo) "get_foo"))

These are Gambit specific things.

Marc