[src/trunk]: src/lib/libc/string clarify what happens when strings overlap.

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

details:   https://anonhg.NetBSD.org/src/rev/8a8e474a61d0
branches:  trunk
changeset: 337080:8a8e474a61d0
user:      christos <christos%NetBSD.org@localhost>
date:      Wed Apr 01 15:20:58 2015 +0000

description:
clarify what happens when strings overlap.

diffstat:

 lib/libc/string/strcpy.3 |  8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diffs (26 lines):

diff -r fae9fd52dce8 -r 8a8e474a61d0 lib/libc/string/strcpy.3
--- a/lib/libc/string/strcpy.3  Wed Apr 01 07:44:18 2015 +0000
+++ b/lib/libc/string/strcpy.3  Wed Apr 01 15:20:58 2015 +0000
@@ -30,9 +30,9 @@
 .\" SUCH DAMAGE.
 .\"
 .\"     from: @(#)strcpy.3     8.1 (Berkeley) 6/4/93
-.\"    $NetBSD: strcpy.3,v 1.20 2009/05/02 09:37:32 wiz Exp $
+.\"    $NetBSD: strcpy.3,v 1.21 2015/04/01 15:20:58 christos Exp $
 .\"
-.Dd May 1, 2009
+.Dd April 1, 2015
 .Dt STRCPY 3
 .Os
 .Sh NAME
@@ -92,6 +92,10 @@
 is
 .Em not
 terminated.
+.Pp
+For portability the source and destination strings should not overlap, because
+implementations are allowed to optimize character movement and the standard
+specify that the results are undefined if they do.
 .Sh RETURN VALUES
 The
 .Fn strcpy