1 files changed, 1 insertions, 0 deletions
diff --git a/ruby.h b/ruby.h
index 5f2448de1a..6988eb0296 100644
--- a/ruby.h
+++ b/ruby.h
@@ -490,6 +490,7 @@ char *rb_id2name _((ID));
 ID rb_to_id _((VALUE));
 
 char *rb_class2name _((VALUE));
+char *rb_obj_classname _((VALUE));
 
 void rb_p _((VALUE));