diff --git a/src/api/plugin.h b/src/api/plugin.h
index ceb85b1..325f6bf 100644
--- a/src/api/plugin.h
+++ b/src/api/plugin.h
@@ -28,7 +28,7 @@
 MYNTEYE_BEGIN_NAMESPACE
 
 class API;
-class Object;
+struct Object;
 
 /**
  * The plugin which could implement processing by yourself.