1 files changed, 1 insertions, 1 deletions
diff --git a/src/object/sp-tref-reference.h b/src/object/sp-tref-reference.h
index 0cad4e912..bff49e3d5 100644
--- a/src/object/sp-tref-reference.h
+++ b/src/object/sp-tref-reference.h
@@ -27,7 +27,7 @@ typedef unsigned int GQuark;
 class SPTRefReference : public Inkscape::URIReference,
                         public Inkscape::XML::NodeObserver {
 public:
-    SPTRefReference(SPObject *owner) : URIReference(owner), subtreeObserved(NULL) {
+    SPTRefReference(SPObject *owner) : URIReference(owner), subtreeObserved(nullptr) {
         updateObserver();
     }