[src/trunk]: src/lib/libc/sys Make the PIOD_READ_AUXV operation more clear

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

details:   https://anonhg.NetBSD.org/src/rev/9cee99353d5c
branches:  trunk
changeset: 821139:9cee99353d5c
user:      kamil <kamil%NetBSD.org@localhost>
date:      Wed Jan 25 17:12:56 2017 +0000

description:
Make the PIOD_READ_AUXV operation more clear

Describe how to set piod_offs.

Sponsored by <The NetBSD Foundation>

diffstat:

 lib/libc/sys/ptrace.2 |  11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diffs (30 lines):

diff -r c7bdde837863 -r 9cee99353d5c lib/libc/sys/ptrace.2
--- a/lib/libc/sys/ptrace.2     Wed Jan 25 17:01:57 2017 +0000
+++ b/lib/libc/sys/ptrace.2     Wed Jan 25 17:12:56 2017 +0000
@@ -1,7 +1,7 @@
-.\"    $NetBSD: ptrace.2,v 1.56 2017/01/15 22:18:11 kamil Exp $
+.\"    $NetBSD: ptrace.2,v 1.57 2017/01/25 17:12:56 kamil Exp $
 .\"
 .\" This file is in the public domain.
-.Dd January 14, 2016
+.Dd January 25, 2016
 .Dt PTRACE 2
 .Os
 .Sh NAME
@@ -285,9 +285,16 @@
 See the description of
 .Dv PT_READ_I
 for the difference between I and D spaces.
+.Pp
 The
 .Dv PIOD_READ_AUXV
 operation can be used to read from the ELF auxiliary vector.
+The
+.Fa piod_offs
+argument sets offset withing the tracee's vector.
+To read from the beginning of it, this value must be set to 0 and casted to
+.Dv (void *) .
+.Pp
 A pointer to the I/O descriptor is passed in the
 .Fa addr
 argument to