diff --git a/src/csn1.h b/src/csn1.h
index 39e6625..e927076 100644
--- a/src/csn1.h
+++ b/src/csn1.h
@@ -212,6 +212,7 @@
 {
   guint8     bits;
   guint8     value;
+  gboolean   keep_bits;
   CSN_DESCR descr;
 } CSN_ChoiceElement_t;