diff --git a/man2/sched_setaffinity.2 b/man2/sched_setaffinity.2
index 74bbde81c..d6663450f 100644
--- a/man2/sched_setaffinity.2
+++ b/man2/sched_setaffinity.2
@@ -238,9 +238,15 @@ being typed as
 .IR "unsigned long\ *" ,
 reflecting the fact that the underlying implementation of CPU
 sets is a simple bit mask.
+.PP
 On success, the raw
 .BR sched_getaffinity ()
-system call returns the size (in bytes) of the
+system call returns the number of bytes placed copied into the
+.I mask
+buffer;
+this will be the minimum of
+.I cpusetsize
+and the size (in bytes) of the
 .I cpumask_t
 data type that is used internally by the kernel to
 represent the CPU set bit mask.