A boolean. If
pointer
is a null pointer (that is, a pointer pointing to address 0) then
t
is returned, otherwise
null-pointer-p
returns
nil
.
The function
null-pointer-p
is used to determine if a pointer is a null pointer. A null pointer is a pointer pointing to address 0.
In the following example a pointer to an
:int
is defined, and tested with
null-pointer-p
. The pointer is then freed, becoming a null pointer, and is once again tested using
null-pointer-p
.
(setq point (fli:allocate-foreign-object :type :int))
(fli:null-pointer-p point)
(fli:free-foreign-object point)
(fli:null-pointer-p point)