1 files changed, 5 insertions, 0 deletions
diff --git a/viz.h b/viz.h
index 80d8cee..a918661 100644
--- a/viz.h
+++ b/viz.h
@@ -1,6 +1,8 @@
 /*
  * Header file for viz.c (visualizing matches)
  */
+#ifndef VIZ__H
+#define VIZ__H
 
 typedef struct match_node_s {
     match_t *m;
@@ -8,3 +10,6 @@ typedef struct match_node_s {
 } match_node_t;
 
 void visualize_match(match_t *m);
+
+#endif
+// vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1