diff --git a/src/class.rs b/src/class.rs
index c0a65592..89f8999c 100644
--- a/src/class.rs
+++ b/src/class.rs
@@ -10,7 +10,9 @@ extern "C" {
     pub fn rb_define_const(klass: Value, name: *const c_char, value: Value);
     pub fn rb_define_method(klass: Value, name: *const c_char, callback: CallbackPtr, argc: Argc);
     pub fn rb_define_module(name: *const c_char) -> Value;
+    pub fn rb_define_module_function(klass: Value, name: *const c_char, callback: CallbackPtr, argc: Argc);
     pub fn rb_define_module_under(outer: Value, name: *const c_char) -> Value;
+    pub fn rb_define_private_method(klass: Value, name: *const c_char, callback: CallbackPtr, argc: Argc);
     pub fn rb_extend_object(object: Value, module: Value);
     pub fn rb_include_module(klass: Value, module: Value);
     pub fn rb_ivar_get(object: Value, name: Id) -> Value;