diff --git a/src/vnet/snap/snap.h b/src/vnet/snap/snap.h
index 7cd453e..08c3a8b 100644
--- a/src/vnet/snap/snap.h
+++ b/src/vnet/snap/snap.h
@@ -165,7 +165,7 @@
   return p ? vec_elt_at_index (sm->protocols, p[0]) : 0;
 }
 
-snap_main_t snap_main;
+extern snap_main_t snap_main;
 
 /* Register given node index to take input for given snap type. */
 void