posix_openpt.3: reflect changes from r. 1.45 of tty_ptm.c

lib/libc/stdlib/posix_openpt.3

@@ -1,4 +1,4 @@
-.\" $NetBSD: posix_openpt.3,v 1.8 2022/09/28 00:35:47 gutteridge Exp $
+.\" $NetBSD: posix_openpt.3,v 1.9 2022/10/04 01:46:18 gutteridge Exp $
 .\"
 .\" Copyright (c) 2004 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -27,7 +27,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd September 28, 2022
+.Dd October 4, 2022
 .Dt POSIX_OPENPT 3
 .Os
 .Sh NAME
@@ -51,9 +51,6 @@ The
 argument has the same meaning as in the
 .Xr open 2
 call.
-However, flags supplied in
-.Fa oflag
-may be ignored if they are unsupported.
 .Sh RETURN VALUES
 If successful,
 .Fn posix_openpt
@@ -75,6 +72,11 @@ This means it is not possible to dynamically test which
 flags are possible to set, and apply a fallback if
 .Er EINVAL
 is received.
+However, this is unlikely to be a concern in practice, as flags such as
+.Dv O_NONBLOCK
+and
+.Dv O_CLOEXEC
+are supported.
 .Sh SEE ALSO
 .Xr ioctl 2 ,
 .Xr open 2 ,