diff --git a/reference/curl/functions/curl-multi-select.xml b/reference/curl/functions/curl-multi-select.xml
index 539153225a..291f8515e6 100644
--- a/reference/curl/functions/curl-multi-select.xml
+++ b/reference/curl/functions/curl-multi-select.xml
@@ -40,7 +40,9 @@
   &reftitle.returnvalues;
   <para>
    On success, returns the number of descriptors contained in 
-   the descriptor sets.  On failure, this function will return -1 on a select failure or timeout (from the underlying select system call).
+   the descriptor sets. This may be 0 if there was no activity on any
+   of the descriptors. On failure, this function will return -1 on a select
+   failure (from the underlying select system call). 
   </para>
  </refsect1>