result of getenv should be treated as read-only.

from OpenBSD.

lib/libc/stdlib/getenv.3

@@ -1,4 +1,4 @@
-.\"	$NetBSD: getenv.3,v 1.12 2002/02/07 07:00:28 ross Exp $
+.\"	$NetBSD: getenv.3,v 1.13 2002/08/10 17:14:50 yamt Exp $
 .\"
 .\" Copyright (c) 1988, 1991, 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -37,7 +37,7 @@
 .\"
 .\"     from: @(#)getenv.3	8.2 (Berkeley) 12/11/93
 .\"
-.Dd December 11, 1993
+.Dd August 11, 2002
 .Dt GETENV 3
 .Os
 .Sh NAME
@@ -123,6 +123,10 @@ return zero if successful; otherwise the global variable
 .Va errno
 is set to indicate the error and a
 \-1 is returned.
+.Pp
+If
+.Fn getenv
+is successful, the string returned should be considered read-only.
 .Sh ERRORS
 .Bl -tag -width Er
 .It Bq Er ENOMEM