diff --git a/src/serverobject.h b/src/serverobject.h
index 5c4d13e3..a8ec325a 100644
--- a/src/serverobject.h
+++ b/src/serverobject.h
@@ -151,9 +151,9 @@ public:
 	{}
 	virtual void setAnimation(v2f frames, float frame_speed, float frame_blend)
 	{}
-	virtual void setBonePosition(std::string bone, v3f position, v3f rotation)
+	virtual void setBonePosition(const std::string &bone, v3f position, v3f rotation)
 	{}
-	virtual void setAttachment(int parent_id, std::string bone, v3f position, v3f rotation)
+	virtual void setAttachment(int parent_id, const std::string &bone, v3f position, v3f rotation)
 	{}
 	virtual ObjectProperties* accessObjectProperties()
 	{ return NULL; }