svn commit: r333192 - head/lib/libc/sys

[Kyle Evans]

Author: kevans
Date: Thu May  3 02:42:13 2018
New Revision: 333192
URL: https://svnweb.freebsd.org/changeset/base/333192

Log:
  fcntl(2): Vaguely document that ENOTTY is possible, with light examples
  
  Reported by:	vs (2006, FreeBSD 6.1-BETA3)
  Reported by:	me (2018, angry debugging session)
  MFC after:	1 month

Modified:
  head/lib/libc/sys/fcntl.2

Modified: head/lib/libc/sys/fcntl.2
==============================================================================
--- head/lib/libc/sys/fcntl.2	Thu May  3 01:23:42 2018	(r333191)
+++ head/lib/libc/sys/fcntl.2	Thu May  3 02:42:13 2018	(r333192)
@@ -28,7 +28,7 @@
 .\"     @(#)fcntl.2	8.2 (Berkeley) 1/12/94
 .\" $FreeBSD$
 .\"
-.Dd July 7, 2016
+.Dd May 2, 2018
 .Dt FCNTL 2
 .Os
 .Sh NAME
@@ -572,6 +572,14 @@ process are already in use,
 or no file descriptors greater than or equal to
 .Fa arg
 are available.
+.It Bq Er ENOTTY
+The
+.Fa fd
+argument is not a valid file descriptor for the requested operation.
+This may be the case if
+.Fa fd
+is a device node, or a descriptor returned by
+.Xr kqueue 2 .
 .It Bq Er ENOLCK
 The argument
 .Fa cmd