1 files changed, 5 insertions, 0 deletions

diff --git a/src/include/gnunet_nt_lib.h b/src/include/gnunet_nt_lib.h
index 144a3daa3..014b4fbe0 100644
--- a/src/include/gnunet_nt_lib.h
+++ b/src/include/gnunet_nt_lib.h
@@ -17,6 +17,11 @@
 
      SPDX-License-Identifier: AGPL3.0-or-later
  */
+
+#if !defined (__GNUNET_UTIL_LIB_H_INSIDE__)
+#error "Only <gnunet_util_lib.h> can be included directly."
+#endif
+
 /**
  * @addtogroup Backbone
  * @{