diff --git a/ecal/core/src/service/ecal_service_server.cpp b/ecal/core/src/service/ecal_service_server.cpp
index 75712af6c6..4e2a3dca40 100644
--- a/ecal/core/src/service/ecal_service_server.cpp
+++ b/ecal/core/src/service/ecal_service_server.cpp
@@ -29,7 +29,7 @@
 
 namespace eCAL
 {
-  CServiceServer::CServiceServer(const std::string & service_name_, const ServerEventCallbackT event_callback_)
+  CServiceServer::CServiceServer(const std::string & service_name_, const ServerEventCallbackT& event_callback_)
     : m_service_server_impl(nullptr)
   {
     // create server implementation