Tests a pointer to see if it is a null pointer.
A FLI pointer.
is used to determine if a pointer is a null pointer. A null pointer is a pointer pointing to address 0.
is a null pointer (that is, a pointer pointing to address 0) then
is true, otherwise
In the following example a pointer to an
is defined, and tested with
. The pointer is then freed, becoming a null pointer, and is once again tested using
(setq point (fli:allocate-foreign-object :type :int))
LispWorks Foreign Language Interface User Guide and Reference Manual - 21 Dec 2009