diff --git a/src/common/clfilter.hpp b/src/common/clfilter.hpp
index d80ad85e..92452351 100644
--- a/src/common/clfilter.hpp
+++ b/src/common/clfilter.hpp
@@ -51,7 +51,11 @@ class CLFilter {
         /// the list of CL-points to be processed
         std::list<CLPoint> clpoints;
         /// tolerance
-        double tol;
+#if 1
+        double tol {};
+#else
+        double tol = 0;
+#endif
 };
 
 } // end namespace