diff --git a/include/chat/common.h b/include/chat/common.h
index ae7896f..6d421e0 100644
--- a/include/chat/common.h
+++ b/include/chat/common.h
@@ -6,6 +6,7 @@
 #include <stdlib.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
+#include <why2/flags.h>
 #include <why2/memory.h>
 
 //DEFINES