diff --git a/src/lib/libc/string/bzero.3 b/src/lib/libc/string/bzero.3
index b3f29793..87a23e20 100644
--- a/src/lib/libc/string/bzero.3
+++ b/src/lib/libc/string/bzero.3
@@ -27,9 +27,9 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.\"	$OpenBSD: bzero.3,v 1.12 2015/11/24 09:14:35 daniel Exp $
+.\"	$OpenBSD: bzero.3,v 1.13 2017/10/12 15:22:32 schwarze Exp $
 .\"
-.Dd $Mdocdate: November 24 2015 $
+.Dd $Mdocdate: October 12 2017 $
 .Dt BZERO 3
 .Os
 .Sh NAME
@@ -64,6 +64,23 @@ password.
 .Sh SEE ALSO
 .Xr memset 3 ,
 .Xr swab 3
+.Sh STANDARDS
+The
+.Fn bzero
+function conforms to the X/Open System Interfaces option of the
+.St -p1003.1-2004
+specification.
+It was removed from the standard in
+.St -p1003.1-2008 ,
+which recommends using
+.Xr memset 3
+instead.
+.Pp
+The
+.Fn explicit_bzero
+function is an
+.Ox
+extension.
 .Sh HISTORY
 The
 .Fn bzero