diff --git a/hardware_interface/include/hardware_interface/handle.hpp b/hardware_interface/include/hardware_interface/handle.hpp
index 2b2372176f..a73b28b4c0 100644
--- a/hardware_interface/include/hardware_interface/handle.hpp
+++ b/hardware_interface/include/hardware_interface/handle.hpp
@@ -35,6 +35,9 @@ class Handle
   {
   }
 
+  /// \brief returns true if handle references a value
+  inline operator bool() const {return value_ptr_ != nullptr;}
+
   HARDWARE_INTERFACE_PUBLIC
   HandleType with_value_ptr(double * value_ptr)
   {
diff --git a/joint_limits_interface/include/joint_limits_interface/joint_limits_interface.hpp b/joint_limits_interface/include/joint_limits_interface/joint_limits_interface.hpp
index a4f893bc11..aeed166bef 100644
--- a/joint_limits_interface/include/joint_limits_interface/joint_limits_interface.hpp
+++ b/joint_limits_interface/include/joint_limits_interface/joint_limits_interface.hpp
@@ -54,9 +54,9 @@
 #include "joint_limits_interface/joint_limits_interface_exception.hpp"
 
 
-#define DEFAULT_POSITION_HANDLE { std::string(), "position" }
-#define DEFAULT_VELOCITY_HANDLE { std::string(), "velocity" }
-#define DEFAULT_COMMAND_HANDLE { std::string(), "position_command" }
+#define DEFAULT_POSITION_HANDLE {std::string(), "position"}
+#define DEFAULT_VELOCITY_HANDLE {std::string(), "velocity"}
+#define DEFAULT_COMMAND_HANDLE {std::string(), "position_command"}
 
 namespace joint_limits_interface
 {