diff --git a/reference/event/event/set.xml b/reference/event/event/set.xml
index 508df7d405..99baad5a02 100644
--- a/reference/event/event/set.xml
+++ b/reference/event/event/set.xml
@@ -56,9 +56,11 @@
     </term>
     <listitem>
      <para>
-      A stream, socket resource, or numeric file descriptor; for signal events
-      pass
+      Stream resource, socket resource, or numeric file descriptor. For timer
+      events pass
       <constant>-1</constant>
+      . For signal events pass the signal number, e.g.
+      <constant>SIGHUP</constant>
       .
      </para>
     </listitem>