According to POSIX, if the src and dst strings overlap, the behavior

is undefined.  Add a warning to that effect.  OK deraadt@ jmc@

1 files changed, 8 insertions, 2 deletions

diff --git a/src/lib/libc/string/memccpy.3 b/src/lib/libc/string/memccpy.3
index 076e8f64ab..98326d6871 100644
--- a/src/lib/libc/string/memccpy.3
+++ b/src/lib/libc/string/memccpy.3
@@ -1,4 +1,4 @@
-.\"     $OpenBSD: memccpy.3,v 1.11 2013/06/05 03:39:23 tedu Exp $
+.\"     $OpenBSD: memccpy.3,v 1.12 2013/09/25 21:49:30 millert Exp $
 .\"
 .\" Copyright (c) 1990, 1991, 1993
 .\"     The Regents of the University of California.  All rights reserved.
@@ -29,7 +29,7 @@
 .\"
 .\"     @(#)memccpy.3   8.1 (Berkeley) 6/9/93
 .\"
-.Dd $Mdocdate: June 5 2013 $
+.Dd $Mdocdate: September 25 2013 $
 .Dt MEMCCPY 3
 .Os
 .Sh NAME
@@ -60,6 +60,12 @@ is returned.
 Otherwise,
 .Fa len
 bytes are copied, and a null pointer is returned.
+.Pp
+If the
+.Fa src
+and
+.Fa dst
+strings overlap, the behavior is undefined.
 .Sh SEE ALSO
 .Xr bcopy 3 ,
 .Xr memcpy 3 ,