diff --git a/man2/pidfd_getfd.2 b/man2/pidfd_getfd.2
index 3fc9c441b..bb771b076 100644
--- a/man2/pidfd_getfd.2
+++ b/man2/pidfd_getfd.2
@@ -116,6 +116,32 @@ Currently, there is no glibc wrapper for this system call; call it using
 .PP
 For a description of PID file descriptors, see
 .BR pidfd_open (2).
+.PP
+The effect of
+.BR pidfd_getfd ()
+is similar to the use of
+.BR SCM_RIGHTS
+messages described in
+.BR unix (7),
+but differs in the following respects:
+.IP \(bu 2
+In order to pass a file descriptor using an
+.BR SCM_RIGHTS
+message,
+the two processes must first establish a UNIX domain socket connection.
+.IP \(bu
+The use of
+.BR SCM_RIGHTS
+requires cooperation on the part of the process whose
+file descriptor is being copied.
+By contrast, no such cooperation is necessary when using
+.BR pidfd_getfd ().
+.IP \(bu
+The ability to use
+.BR pidfd_getfd ()
+is restricted by a
+.BR PTRACE_MODE_ATTACH_REALCREDS
+ptrace  access  mode check.
 .SH SEE ALSO
 .BR clone3 (2),
 .BR dup (2),