diff --git a/include/ruby/ractor.h b/include/ruby/ractor.h
index 239df9c04c..1d6687456c 100644
--- a/include/ruby/ractor.h
+++ b/include/ruby/ractor.h
@@ -32,6 +32,7 @@ void rb_ractor_stderr_set(VALUE);
 
 rb_ractor_local_key_t rb_ractor_local_storage_value_newkey(void);
 VALUE rb_ractor_local_storage_value(rb_ractor_local_key_t key);
+bool rb_ractor_local_storage_value_lookup(rb_ractor_local_key_t key, VALUE *val);
 void  rb_ractor_local_storage_value_set(rb_ractor_local_key_t key, VALUE val);
 
 RUBY_EXTERN const struct rb_ractor_local_storage_type rb_ractor_local_storage_type_free;
@@ -41,6 +42,9 @@ rb_ractor_local_key_t rb_ractor_local_storage_ptr_newkey(const struct rb_ractor_
 void *rb_ractor_local_storage_ptr(rb_ractor_local_key_t key);
 void  rb_ractor_local_storage_ptr_set(rb_ractor_local_key_t key, void *ptr);
 
+VALUE rb_ractor_make_shareable(VALUE obj);
+VALUE rb_ractor_make_shareable_copy(VALUE obj);
+
 RUBY_SYMBOL_EXPORT_END
 
 #define RB_OBJ_SHAREABLE_P(obj) FL_TEST_RAW((obj), RUBY_FL_SHAREABLE)
@@ -61,7 +65,4 @@ rb_ractor_shareable_p(VALUE obj)
     }
 }
 
-VALUE rb_ractor_make_shareable(VALUE obj);
-VALUE rb_ractor_make_shareable_copy(VALUE obj);
-
 #endif /* RUBY_RACTOR_H */
diff --git a/ractor.c b/ractor.c
index d9a8e07a79..420b2051b2 100644
--- a/ractor.c
+++ b/ractor.c
@@ -3128,6 +3128,17 @@ rb_ractor_local_storage_value(rb_ractor_local_key_t key)
     }
 }
 
+bool
+rb_ractor_local_storage_value_lookup(rb_ractor_local_key_t key, VALUE *val)
+{
+    if (ractor_local_ref(key, (void **)val)) {
+        return true;
+    }
+    else {
+        return false;
+    }
+}
+
 void
 rb_ractor_local_storage_value_set(rb_ractor_local_key_t key, VALUE val)
 {
diff --git a/vm_core.h b/vm_core.h
index cfce3af59d..5f8d4ab876 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -1085,9 +1085,11 @@ typedef struct {
     unsigned int is_isolated: 1;        /* bool */
 } rb_proc_t;
 
+RUBY_SYMBOL_EXPORT_BEGIN
 VALUE rb_proc_isolate(VALUE self);
 VALUE rb_proc_isolate_bang(VALUE self);
 VALUE rb_proc_ractor_make_shareable(VALUE self);
+RUBY_SYMBOL_EXPORT_END
 
 typedef struct {
     VALUE flags; /* imemo header */