diff --git a/man2/sigaction.2 b/man2/sigaction.2
index dbccd42ea..db2c0cd4c 100644
--- a/man2/sigaction.2
+++ b/man2/sigaction.2
@@ -468,7 +468,11 @@ field by
 .BR poll (2).
 The
 .I si_fd
-field indicates the file descriptor for which the I/O event occurred.
+field indicates the file descriptor for which the I/O event occurred;
+for further details, see the description of
+.BR F_SETSIG 
+in
+.BR fcntl (2).
 .IP *
 .BR SIGSYS ,
 generated (since Linux 3.5)