diff --git a/man2/sigreturn.2 b/man2/sigreturn.2
index 7a3e3fc0c..73baca373 100644
--- a/man2/sigreturn.2
+++ b/man2/sigreturn.2
@@ -79,6 +79,14 @@ exists only to allow the implementation of signal handlers.
 It should
 .B never
 be called directly.
+(Indeed, a simple
+.BR sigreturn ()
+.\" See sysdeps/unix/sysv/linux/sigreturn.c and
+.\" signal/sigreturn.c in the glibc source
+wrapper in the GNU C library simply returns -1, with
+.I errno
+set to
+.BR ENOSYS .)
 Details of the arguments (if any) passed to
 .BR sigreturn ()
 vary depending on the architecture.