how to access c-array member in c-structure?

[Park SungMin]

I read https://www.gnu.org/software/guile/manual/html_node/Foreign-Structs.html 
..

follow c struct

struct foo {
    int a;
    int b[4];
}
then 
(let ((foo-type (list int (make-list 4 int))))
   (parse-c-struct (make-c-struct foo-type (list 1 (list 1 2 3 4))) foo-type))
is run well.

but,
typedef struct {
  int a;
  int b;
  int c[20000];
} Foo;

Foo make_foo(int a, int b) {
  Foo foo = {.a = a, .b = b};
  return foo;
}

(let ((c-type (list int int (make-list 20000 int))))
    (parse-c-struct
     ((pointer->procedure
       c-type
       (dynamic-func "make_foo" libfoo)
       (list int int))
      4 11)
     c-type))

also run well…but seems less effective.(if more bigger size…2000000??) 
 is it possible pass or return as bytevector or pointer to c-array?
(let ((c-type (list int int ‘*)) ….)  is different type….(when i try it, guile 
shutdown)