* @param[in] grabModeVector The Dali::Vector of grab modes for the keys
* @return Dali::Vector Size is zero when error occurs, true/false if the grab succeeds/fails.
*/
-DALI_IMPORT_API Dali::Vector<bool> GrabKeyList( Window window, const Dali::Vector<Dali::KEY> daliKeyVector, const Dali::Vector<KeyGrabMode> grabModeVector);
+DALI_IMPORT_API Dali::Vector<bool> GrabKeyList( Window window, const Dali::Vector<Dali::KEY>& daliKeyVector, const Dali::Vector<KeyGrabMode>& grabModeVector);
/**
* @note If this function is called between key down and up events of a grabbed key,
* an application doesn't receive the key up event.
*/
-DALI_IMPORT_API Dali::Vector<bool> UngrabKeyList( Window window, const Dali::Vector<Dali::KEY> daliKeyVector );
+DALI_IMPORT_API Dali::Vector<bool> UngrabKeyList( Window window, const Dali::Vector<Dali::KEY>& daliKeyVector );
} // namespace KeyGrab