usr/src/lib/libc/port/gen/env_data.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*
  28  *      Copyright (c) 1988 AT&T
  29  *      All Rights Reserved.
  30  */
  31
  32 #pragma ident   "%Z%%M% %I%     %E% SMI"
  33
  34 /*
  35  * NOTE: The environment symbol pair may also occur in crt1.o.  The definitions
  36  * within crt1.o are required for the generation of ABI compliant applications
  37  * (see bugid 1181124).  No other symbol definitions should be added to this
  38  * file.
  39  */
  40
  41 /*
  42  * The original SVR3 ABI states:
  43  *
  44  * Application Constraints
  45  * As described above, libsys provides symbols for applications. In a few cases,
  46  * however, an application is obliged to provide symbols for the library.
  47  *
  48  * extern char **environ;
  49  *     Normally, this symbol is synonymous with environ, as
  50  *     exec(BA_OS) describes.  This isn't always true, though, because
  51  *     ANSI C does not define environ.  Thus, an ANSI C-conforming
  52  *     application can define its own environ symbol, unrelated to the pro-
  53  *     cess environment.  If the application defines environ and intends it
  54  *     to have the System V Interface Definition, Third Edition semantics, it
  55  *     must also define _environ so that the two symbols refer to the same
  56  *     data object.
  57  *
  58  * The ABI description implies that the process environment should use
  59  * _environ and that nothing in libc should make reference to the unadorned
  60  * "environ" symbol.  This way, an application can define and use a symbol
  61  * named "environ" for its own purposes without affecting the actual
  62  * process environment.
  63  */
  64
  65 #pragma weak environ = _environ
  66 const char **_environ = 0;