diff --git a/lib/urldata.h b/lib/urldata.h
index dece629fda..0d4a11a8b2 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -677,7 +677,7 @@ struct UserDefined {
   bool reuse_fresh;      /* do not re-use an existing connection  */
   bool expect100header;  /* TRUE if we added Expect: 100-continue */
   bool ftp_use_epsv;     /* if EPSV is to be attempted or not */
-  bool no_signal;
+  bool no_signal;        /* do not use any signal/alarm handler */
 
   bool global_dns_cache;
 };