The functions allocate-dynamic-foreign-object
, allocate-foreign-object
, alloca
, and malloc
can take the keyword arguments:type
and:pointer-type
. It is important to understand the difference between these two arguments.
The:type
argument is used to specify the name of the FLI type to allocate. Once such an object has been allocated a foreign pointer of type(:pointer
type)
is return, which points to the allocated type. Without this pointer it would not be possible to refer to the object.
The:pointer-type
argument is used to specify an FLI pointer type. If it is used a pointer type of the form(:pointer
type) must be specified with it. The function then allocates an object of type type, and a pointer to the object of type type is returned.
In this first example you can see how to allocate an integer in C, and in LispWorks using the:type
and the:pointer-type
arguments.
C > (int *)malloc(sizeof(int)) FLI > (fli:allocate-foreign-object :type :int) => #<Pointer to type :INT = #x007E1A60> FLI > (fli:allocate-foreign-objects :pointer-type '(:pointer :int)) => #<Pointer to type :INT = #x007E1A60>