diff --git a/man2/clock_getres.2 b/man2/clock_getres.2
index 2949df5a6..6e2e49411 100644
--- a/man2/clock_getres.2
+++ b/man2/clock_getres.2
@@ -243,6 +243,20 @@ are available.
 (See also
 .BR sysconf (3).)
 .SH NOTES
+POSIX.1 specifies the following:
+.RS
+.PP
+Setting the value of the
+.B CLOCK_REALTIME
+clock via
+.BR clock_settime (2)
+shall have no effect on threads that are blocked waiting for a relative time
+service based upon this clock, including the
+.BR nanosleep ()
+function; nor on the expiration of relative timers based upon this clock.
+Consequently, these time services shall expire when the requested relative
+interval elapses, independently of the new or old value of the clock.
+.\"
 .SS Historical note for SMP systems
 Before Linux added kernel support for
 .B CLOCK_PROCESS_CPUTIME_ID