1 files changed, 3 insertions, 1 deletions
diff --git a/roff.7 b/roff.7
index 7a60cf30..d9e0b999 100644
--- a/roff.7
+++ b/roff.7
@@ -878,12 +878,14 @@ request are discarded.
 Change the output line length.
 Its syntax is as follows:
 .Pp
-.D1 Pf . Cm \&ll Op Ar width
+.D1 Pf . Cm \&ll Op Oo +|- Oc Ns Ar width
 .Pp
 If the
 .Ar width
 argument is omitted, the line length is reset to its previous value.
 The default setting for terminal output is 78n.
+If a sign is given, the line length is added to or subtracted from;
+otherwise, it is set to the provided value.
 Using this request in new manuals is discouraged for several reasons,
 among others because it overrides the
 .Xr mandoc 1