diff --git a/include/maxscale/protocol/mysql.h b/include/maxscale/protocol/mysql.h
index a5dad3d93..02b6c9d10 100644
--- a/include/maxscale/protocol/mysql.h
+++ b/include/maxscale/protocol/mysql.h
@@ -307,11 +307,10 @@ typedef enum
     MXS_COM_RESET_CONNECTION    = 31,
     MXS_COM_STMT_BULK_EXECUTE   = 0xfa,
     MXS_COM_MULTI               = 0xfe,
-    MXS_COM_END
+    MXS_COM_END,
+    MXS_COM_UNDEFINED = -1
 } mxs_mysql_cmd_t;
 
-static const mxs_mysql_cmd_t MXS_COM_UNDEFINED = (mxs_mysql_cmd_t) -1;
-
 /**
  * A GWBUF property with this name will contain the latest GTID in string form.
  * This information is only available in OK packets.