diff --git a/ruamoko/include/runtime.h b/ruamoko/include/runtime.h
index 276d270fb..849b9be1e 100644
--- a/ruamoko/include/runtime.h
+++ b/ruamoko/include/runtime.h
@@ -45,7 +45,7 @@ typedef enum {
 //obj_error_handler obj_set_error_handler (objc_error_handler func);
 @extern IMP obj_msg_lookup (id receiver, SEL op);
 @extern IMP obj_msg_lookup_super (Super class, SEL op);
-@extern @param obj_msg_sendv (id receiver, SEL op, @va_list args);
+@extern @attribute(void_return) void obj_msg_sendv (id receiver, SEL op, @va_list args);
 @extern BOOL obj_decrement_ref_was_zero (id object);
 @extern BOOL obj_increment_ref_was_zero (id object);
 @extern void *obj_malloc (int size);
diff --git a/ruamoko/lib/Object.r b/ruamoko/lib/Object.r
index 03a1519ad..711721d1d 100644
--- a/ruamoko/lib/Object.r
+++ b/ruamoko/lib/Object.r
@@ -17,7 +17,7 @@ IMP (id receiver, SEL op) obj_msg_lookup = #0;
 IMP (Super class, SEL op) obj_msg_lookup_super = #0;
 id (id receiver, SEL op, ...) obj_msgSend = #0;
 id obj_msgSend_super (Super *class, SEL op, ...) = #0;
-@param (id receiver, SEL op, @va_list args) obj_msg_sendv = #0;
+@attribute(void_return) void obj_msg_sendv (id receiver, SEL op, @va_list args) = #0;
 int obj_decrement_retaincount (id object) = #0;
 int obj_increment_retaincount (id object) = #0;
 int obj_get_retaincount (id object) = #0;