svn commit: r359196 - stable/11/lib/libc/sys

[Alan Somers]

Author: asomers
Date: Sat Mar 21 18:24:33 2020
New Revision: 359196
URL: https://svnweb.freebsd.org/changeset/base/359196

Log:
  MFC r352231:
  
  getsockopt.2: clarify that SO_TIMESTAMP is not 100% reliable
  
  When SO_TIMESTAMP is set, the kernel will attempt to attach a timestamp as
  ancillary data to each IP datagram that is received on the socket. However,
  it may fail, for example due to insufficient memory. In that case the
  packet will still be received but not timestamp will be attached.
  
  Reviewed by:	kib
  Differential Revision:	https://reviews.freebsd.org/D21607

Modified:
  stable/11/lib/libc/sys/getsockopt.2
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/lib/libc/sys/getsockopt.2
==============================================================================
--- stable/11/lib/libc/sys/getsockopt.2	Sat Mar 21 16:12:19 2020	(r359195)
+++ stable/11/lib/libc/sys/getsockopt.2	Sat Mar 21 18:24:33 2020	(r359196)
@@ -28,7 +28,7 @@
 .\"     @(#)getsockopt.2	8.4 (Berkeley) 5/2/95
 .\" $FreeBSD$
 .\"
-.Dd April 5, 2013
+.Dd September 11, 2019
 .Dt GETSOCKOPT 2
 .Os
 .Sh NAME
@@ -419,7 +419,8 @@ option is enabled on a
 .Dv SOCK_DGRAM
 socket, the
 .Xr recvmsg 2
-call will return a timestamp corresponding to when the datagram was received.
+call may return a timestamp corresponding to when the datagram was received.
+However, it may not, for example due to a resource shortage.
 The
 .Va msg_control
 field in the