diff --git a/man2/clock_getres.2 b/man2/clock_getres.2
index 5395f9fbf..2eb8d97a4 100644
--- a/man2/clock_getres.2
+++ b/man2/clock_getres.2
@@ -203,9 +203,11 @@ or similar.
 .BR CLOCK_PROCESS_CPUTIME_ID " (since Linux 2.6.12)"
 Per-process CPU-time clock
 (measures CPU time consumed by all threads in the process).
+On Linux, this clock is not settable.
 .TP
 .BR CLOCK_THREAD_CPUTIME_ID " (since Linux 2.6.12)"
 Thread-specific CPU-time clock.
+On Linux, this clock is not settable.
 .SH RETURN VALUE
 .BR clock_gettime (),
 .BR clock_settime (),