Subject: AW: [clisp-list] question about ffi: (c-ptr nil) vs c-pointer

From: "Hoehle, Joerg-Cyril" <[email-masked]>
Date: Wed Mar 27 08:35:11 2002

dan.stanger wrote:
> Is the construction (FFI:C-PTR nil) equivalent to FFI:C-POINTER?

No, it cannot be. C_POINTER is really opaque. It will even create an FOREIGN-ADDRESS for a NULL pointer. While C-PTR rejects that.

Also, C-PTR NIL cannot create a Lisp object of type FOREIGN-ADDRESS.

BTW, I never used NIL as a foreign type. Could you provide an example where you think it is useful?

Thanks,
	Jorg Hohle.