diff --git a/src/handler.cpp b/src/handler.cpp
index 89c9913..af8ef90 100644
--- a/src/handler.cpp
+++ b/src/handler.cpp
@@ -346,7 +346,7 @@
 
 // This function works like getSubTreePaths() but only matching id with
 // the leaf-name instead of full path.
-std::vector<std::string> getSubTreePathsById(
+static std::vector<std::string> getSubTreePathsById(
     const InterfaceMapType& interfaceMap, const std::string& id,
     const std::string& objectPath, std::vector<std::string>& interfaces)
 {