[src/trunk]: src/lib/libc/sys mention sig == 0

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/0d197e707291
branches:  trunk
changeset: 330460:0d197e707291
user:      christos <christos%NetBSD.org@localhost>
date:      Wed Jul 09 16:06:47 2014 +0000

description:
mention sig == 0

diffstat:

 lib/libc/sys/kill.2 |  12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)

diffs (33 lines):

diff -r faefe0c26f0a -r 0d197e707291 lib/libc/sys/kill.2
--- a/lib/libc/sys/kill.2       Wed Jul 09 15:56:12 2014 +0000
+++ b/lib/libc/sys/kill.2       Wed Jul 09 16:06:47 2014 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: kill.2,v 1.21 2008/07/13 15:16:26 dholland Exp $
+.\"    $NetBSD: kill.2,v 1.22 2014/07/09 16:06:47 christos Exp $
 .\"
 .\" Copyright (c) 1980, 1991, 1993
 .\"    The Regents of the University of California.  All rights reserved.
@@ -29,7 +29,7 @@
 .\"
 .\"     @(#)kill.2     8.3 (Berkeley) 4/19/94
 .\"
-.Dd April 19, 1994
+.Dd July 9, 2014
 .Dt KILL 2
 .Os
 .Sh NAME
@@ -94,6 +94,14 @@
 is equal to the absolute value of the process number.
 This is a variant of
 .Xr killpg 3 .
+.Pp
+If
+.Fa sig
+is equal to
+.Dv 0 ,
+then no signal is sent to the process ID or process group ID, but error
+checking is performed.
+This can be used to check if the process ID or process group ID exist.
 .Sh RETURN VALUES
 Upon successful completion, a value of 0 is returned.
 Otherwise, a value of \-1 is returned and