diff --git a/man2/pidfd_open.2 b/man2/pidfd_open.2
index 9a5aa7e36..3fd813845 100644
--- a/man2/pidfd_open.2
+++ b/man2/pidfd_open.2
@@ -88,7 +88,10 @@ and
 When the process that it refers to terminates,
 these interfaces indicate the file descriptor as readable.
 Note, however, that in the current implementation,
-nothing can be read from the file descriptor.
+nothing can be read from the file descriptor
+.RB ( read (2)
+on the file descriptor fails with the error
+.BR EINVAL ).
 .PP
 The
 .BR pidfd_open ()