--- /dev/null
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/*
+ * The contents of this file are subject to the Mozilla Public
+ * License Version 1.1 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of
+ * the License at http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS
+ * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
+ * implied. See the License for the specific language governing
+ * rights and limitations under the License.
+ *
+ * The Original Code is the Netscape Portable Runtime (NSPR).
+ *
+ * The Initial Developer of the Original Code is Netscape
+ * Communications Corporation. Portions created by Netscape are
+ * Copyright (C) 1998-2000 Netscape Communications Corporation. All
+ * Rights Reserved.
+ *
+ * Contributor(s):
+ *
+ * Alternatively, the contents of this file may be used under the
+ * terms of the GNU General Public License Version 2 or later (the
+ * "GPL"), in which case the provisions of the GPL are applicable
+ * instead of those above. If you wish to allow use of your
+ * version of this file only under the terms of the GPL and not to
+ * allow others to use your version of this file under the MPL,
+ * indicate your decision by deleting the provisions above and
+ * replace them with the notice and other provisions requiored by
+ * the GPL. If you do not delete the provisions above, a recipient
+ * may use your version of this file under either the MPL or the
+ * GPL.
+ */
+
+#ifndef prenv_h___
+#define prenv_h___
+
+#include <security_asn1/prtypes.h>
+
+/*******************************************************************************/
+/*******************************************************************************/
+/****************** THESE FUNCTIONS MAY NOT BE THREAD SAFE *********************/
+/*******************************************************************************/
+/*******************************************************************************/
+
+PR_BEGIN_EXTERN_C
+
+/*
+** PR_GetEnv() -- Retrieve value of environment variable
+**
+** Description:
+** PR_GetEnv() is modeled on Unix getenv().
+**
+**
+** Inputs:
+** var -- The name of the environment variable
+**
+** Returns:
+** The value of the environment variable 'var' or NULL if
+** the variable is undefined.
+**
+** Restrictions:
+** You'd think that a POSIX getenv(), putenv() would be
+** consistently implemented everywhere. Surprise! It is not. On
+** some platforms, a putenv() where the argument is of
+** the form "name" causes the named environment variable to
+** be un-set; that is: a subsequent getenv() returns NULL. On
+** other platforms, the putenv() fails, on others, it is a
+** no-op. Similarly, a putenv() where the argument is of the
+** form "name=" causes the named environment variable to be
+** un-set; a subsequent call to getenv() returns NULL. On
+** other platforms, a subsequent call to getenv() returns a
+** pointer to a null-string (a byte of zero).
+**
+** PR_GetEnv(), PR_SetEnv() provide a consistent behavior
+** across all supported platforms. There are, however, some
+** restrictions and some practices you must use to achieve
+** consistent results everywhere.
+**
+** When manipulating the environment there is no way to un-set
+** an environment variable across all platforms. We suggest
+** you interpret the return of a pointer to null-string to
+** mean the same as a return of NULL from PR_GetEnv().
+**
+** A call to PR_SetEnv() where the parameter is of the form
+** "name" will return PR_FAILURE; the environment remains
+** unchanged. A call to PR_SetEnv() where the parameter is
+** of the form "name=" may un-set the envrionment variable on
+** some platforms; on others it may set the value of the
+** environment variable to the null-string.
+**
+** For example, to test for NULL return or return of the
+** null-string from PR_GetEnv(), use the following code
+** fragment:
+**
+** char *val = PR_GetEnv("foo");
+** if ((NULL == val) || ('\0' == *val)) {
+** ... interpret this as un-set ...
+** }
+**
+** The caller must ensure that the string passed
+** to PR_SetEnv() is persistent. That is: The string should
+** not be on the stack, where it can be overwritten
+** on return from the function calling PR_SetEnv().
+** Similarly, the string passed to PR_SetEnv() must not be
+** overwritten by other actions of the process. ... Some
+** platforms use the string by reference rather than copying
+** it into the environment space. ... You have been warned!
+**
+** Use of platform-native functions that manipulate the
+** environment (getenv(), putenv(),
+** SetEnvironmentVariable(), etc.) must not be used with
+** NSPR's similar functions. The platform-native functions
+** may not be thread safe and/or may operate on different
+** conceptual environment space than that operated upon by
+** NSPR's functions or other environment manipulating
+** functions on the same platform. (!)
+**
+*/
+NSPR_API(char*) PR_GetEnv(const char *var);
+
+/*
+** PR_SetEnv() -- set, unset or change an environment variable
+**
+** Description:
+** PR_SetEnv() is modeled on the Unix putenv() function.
+**
+** Inputs:
+** string -- pointer to a caller supplied
+** constant, persistent string of the form name=value. Where
+** name is the name of the environment variable to be set or
+** changed; value is the value assigned to the variable.
+**
+** Returns:
+** PRStatus.
+**
+** Restrictions:
+** See the Restrictions documented in the description of
+** PR_GetEnv() in this header file.
+**
+**
+*/
+NSPR_API(PRStatus) PR_SetEnv(const char *string);
+
+/*
+** DEPRECATED. Use PR_SetEnv() instead.
+*/
+#ifdef XP_MAC
+NSPR_API(PRIntn) PR_PutEnv(const char *string);
+#endif
+
+PR_END_EXTERN_C
+
+#endif /* prenv_h___ */
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