diff --git a/ext/v8/rr.cpp b/ext/v8/rr.cpp
index 0fabcf4..355e465 100644
--- a/ext/v8/rr.cpp
+++ b/ext/v8/rr.cpp
@@ -40,6 +40,13 @@ VALUE rr_const_get(const char *name) {
   return rb_const_get(V8_C, rb_intern(name));
 }
 
+VALUE rr_define_finalizer(VALUE object, void* finalizer, VALUE data) {
+  VALUE finalizer_proc = rb_proc_new((VALUE (*)(...))finalizer, data);
+  rb_iv_set(finalizer_proc, "data", data);
+  VALUE ospace = rb_const_get(rb_cObject, rb_intern("ObjectSpace"));
+  rb_funcall(ospace, rb_intern("define_finalizer"), 2, object, finalizer_proc);
+}
+
 VALUE rr_v82rb(Handle<Value> value) {
   if (value.IsEmpty()) {
     return rr_v8_value_empty();
diff --git a/ext/v8/rr.h b/ext/v8/rr.h
index e01cf3d..601f69f 100644
--- a/ext/v8/rr.h
+++ b/ext/v8/rr.h
@@ -11,6 +11,10 @@ VALUE rr_define_class(const char *name, VALUE superclass = rb_cObject);
 VALUE rr_define_module(const char *name);
 VALUE rr_define_const(const char *name, VALUE value);
 VALUE rr_const_get(const char *name);
+VALUE rr_define_finalizer(VALUE object, void* finalizer, VALUE data);
+
+extern "C" VALUE rb_proc_new(VALUE (*)(ANYARGS/* VALUE yieldarg[, VALUE procarg] */), VALUE);
+
 
 VALUE rr_v82rb(v8::Handle<v8::Value> value);
 VALUE rr_v82rb(v8::Handle<v8::Boolean> value);
diff --git a/ext/v8/v8_weakref.cpp b/ext/v8/v8_weakref.cpp
index e257e68..f8688ec 100644
--- a/ext/v8/v8_weakref.cpp
+++ b/ext/v8/v8_weakref.cpp
@@ -12,8 +12,7 @@ v8_weakref::v8_weakref(VALUE object) {
 void v8_weakref::set(VALUE value) {
   this->object_id = rb_obj_id(value);
   VALUE data = Data_Wrap_Struct(rb_cObject, 0, 0, this);
-  VALUE finalizer = rb_proc_new((VALUE (*)(...))v8_weakref_finalize, data);
-  rb_funcall(v8_weakref_objectspace(), rb_intern("define_finalizer"), 2, value, finalizer);
+  rr_define_finalizer(value,(void*)v8_weakref_finalize, data);
 }
 
 VALUE v8_weakref::get() {
diff --git a/ext/v8/v8_weakref.h b/ext/v8/v8_weakref.h
index c080fed..96458c7 100644
--- a/ext/v8/v8_weakref.h
+++ b/ext/v8/v8_weakref.h
@@ -3,6 +3,7 @@
 
 #include <v8.h>
 #include "ruby.h"
+#include "rr.h"
 
 struct v8_weakref  {
   v8_weakref(VALUE object);
@@ -21,6 +22,6 @@ VALUE v8_weakref_objectspace();
 VALUE v8_weakref_nil(VALUE nil, VALUE exception);
 VALUE v8_weakref_id2ref(VALUE id);
 
-extern "C" VALUE rb_proc_new(VALUE (*)(ANYARGS/* VALUE yieldarg[, VALUE procarg] */), VALUE);
+// extern "C" VALUE rb_proc_new(VALUE (*)(ANYARGS/* VALUE yieldarg[, VALUE procarg] */), VALUE);
 
 #endif