Make the second, section number argument of .Xr mandatory.

In fact, we have been requiring it for many years.
The only reason to not warn when it was missing
was excessive traditionalism - it was optional in 4.4BSD.

1 files changed, 5 insertions, 6 deletions

diff --git a/share/man/man7/mdoc.7 b/share/man/man7/mdoc.7
index 1a54280fbf5..f46b578a174 100644
--- a/share/man/man7/mdoc.7
+++ b/share/man/man7/mdoc.7
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: mdoc.7,v 1.145 2016/10/11 17:30:28 schwarze Exp $
+.\"	$OpenBSD: mdoc.7,v 1.146 2016/12/28 17:21:17 schwarze Exp $
 .\"
 .\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
 .\" Copyright (c) 2010, 2011, 2013 Ingo Schwarze <schwarze@openbsd.org>
@@ -15,7 +15,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: October 11 2016 $
+.Dd $Mdocdate: December 28 2016 $
 .Dt MDOC 7
 .Os
 .Sh NAME
@@ -2726,14 +2726,13 @@ Link to another manual
 .Pq Qq cross-reference .
 Its syntax is as follows:
 .Pp
-.D1 Pf \. Sx \&Xr Ar name Op section
+.D1 Pf \. Sx \&Xr Ar name section
 .Pp
 Cross reference the
 .Ar name
 and
 .Ar section
-number of another man page;
-omitting the section number is rarely useful.
+number of another man page.
 .Pp
 Examples:
 .Dl \&.Xr mandoc 1
@@ -3045,7 +3044,7 @@ then the macro accepts an arbitrary number of arguments.
 .It Sx \&Ux  Ta    Yes      Ta    Yes      Ta    n
 .It Sx \&Va  Ta    Yes      Ta    Yes      Ta    n
 .It Sx \&Vt  Ta    Yes      Ta    Yes      Ta    >0
-.It Sx \&Xr  Ta    Yes      Ta    Yes      Ta    >0
+.It Sx \&Xr  Ta    Yes      Ta    Yes      Ta    2
 .It Sx \&br  Ta    \&No     Ta    \&No     Ta    0
 .It Sx \&sp  Ta    \&No     Ta    \&No     Ta    1
 .El