diff --git a/dune/solvers/norms/pnorm.hh b/dune/solvers/norms/pnorm.hh
index 04f2354870efaf3f5c92a91c6fe2ed7874697d28..b4faa70f0b197f3ce32af8193b3fbae9dbc042d0 100644
--- a/dune/solvers/norms/pnorm.hh
+++ b/dune/solvers/norms/pnorm.hh
@@ -1,7 +1,7 @@
 // -*- tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 // vi: set et ts=8 sw=4 sts=4:
-#ifndef __PNORM__HH__
-#define __PNORM__HH__
+#ifndef DUNE_SOLVERS_PNORM_HH
+#define DUNE_SOLVERS_PNORM_HH
 
 #include <cmath>