CFFI provides support for stack and heap C memory allocation.
Stack allocation, done with with-foreign-object, is sometimes
called “dynamic” allocation in Lisp, because memory allocated as
such has dynamic extent, much as with let bindings of special
variables.
This should not be confused with what C calls “dynamic” allocation,
or that done with malloc and friends. This sort of heap
allocation is done with foreign-alloc, creating objects that
exist until freed with foreign-free.