-SCM_INTERNAL SCM scm_c_weak_vector_ref (SCM v, size_t k);
-SCM_INTERNAL void scm_c_weak_vector_set_x (SCM v, size_t k, SCM x);
+SCM_API SCM scm_weak_vector_length (SCM v);
+SCM_API SCM scm_weak_vector_ref (SCM v, SCM k);
+SCM_API SCM scm_weak_vector_set_x (SCM v, SCM k, SCM x);
+
+SCM_API SCM scm_c_make_weak_vector (size_t len, SCM fill);
+SCM_API int scm_is_weak_vector (SCM obj);
+SCM_API size_t scm_c_weak_vector_length (SCM vec);
+SCM_API SCM scm_c_weak_vector_ref (SCM v, size_t k);
+SCM_API void scm_c_weak_vector_set_x (SCM v, size_t k, SCM x);