A null pointer.
fli
The variable *null-pointer* contains a (:pointer :void) with address 0.
*null-pointer*
(:pointer :void)
This provides a simple way to pass a null pointer when needed.
(fli:pointer-address fli:*null-pointer*)
=>
0
(fli:null-pointer-p fli:*null-pointer*)
T
pointer-address null-pointer-p :pointer
LispWorks Foreign Language Interface User Guide and Reference Manual - 29 Sep 2017