diff --git a/dbus/dbusutil.hpp b/dbus/dbusutil.hpp
index ff606a4..ee8d166 100644
--- a/dbus/dbusutil.hpp
+++ b/dbus/dbusutil.hpp
@@ -28,6 +28,7 @@
     }
 };
 
+std::string getSensorUnit(const std::string& type);
 std::string getSensorPath(const std::string& type, const std::string& id);
 std::string getMatch(const std::string& path);
 void scaleSensorReading(const double min, const double max, double& value);