The function pointer-pointer-type
returns the pointer type of the foreign pointer pointer.
(setq point (fli:allocate-foreign-object :type :int))
=>
#<Pointer to type :INT = #x007F3DF0>
(fli:pointer-pointer-type point)
=>
(:POINTER :INT)
(fli:free-foreign-object point)
=>
#<Pointer to type :INT = #x00000000>
LispWorks Foreign Language Interface User Guide and Reference Manual - 29 Sep 2017