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/* -*- 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 required 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.
*/
/*
** File: prlock.h
** Description: API to basic locking functions of NSPR.
**
**
** NSPR provides basic locking mechanisms for thread synchronization. Locks
** are lightweight resource contention controls that prevent multiple threads
** from accessing something (code/data) simultaneously.
**/
#ifndef prlock_h___
#define prlock_h___
#include "prtypes.h"
PR_BEGIN_EXTERN_C
/**********************************************************************/
/************************* TYPES AND CONSTANTS ************************/
/**********************************************************************/
/*
* PRLock --
*
* NSPR represents the lock as an opaque entity to the client of the
* API. All routines operate on a pointer to this opaque entity.
*/
typedef struct PRLock PRLock;
/**********************************************************************/
/****************************** FUNCTIONS *****************************/
/**********************************************************************/
/***********************************************************************
** FUNCTION: PR_NewLock
** DESCRIPTION:
** Returns a pointer to a newly created opaque lock object.
** INPUTS: void
** OUTPUTS: void
** RETURN: PRLock*
** If the lock can not be created because of resource constraints, NULL
** is returned.
**
***********************************************************************/
NSPR_API(PRLock*) PR_NewLock(void);
/***********************************************************************
** FUNCTION: PR_DestroyLock
** DESCRIPTION:
** Destroys a given opaque lock object.
** INPUTS: PRLock *lock
** Lock to be freed.
** OUTPUTS: void
** RETURN: None
***********************************************************************/
NSPR_API(void) PR_DestroyLock(PRLock *lock);
/***********************************************************************
** FUNCTION: PR_Lock
** DESCRIPTION:
** Lock a lock.
** INPUTS: PRLock *lock
** Lock to locked.
** OUTPUTS: void
** RETURN: None
***********************************************************************/
NSPR_API(void) PR_Lock(PRLock *lock);
/***********************************************************************
** FUNCTION: PR_Unlock
** DESCRIPTION:
** Unlock a lock. Unlocking an unlocked lock has undefined results.
** INPUTS: PRLock *lock
** Lock to unlocked.
** OUTPUTS: void
** RETURN: PR_STATUS
** Returns PR_FAILURE if the caller does not own the lock.
***********************************************************************/
NSPR_API(PRStatus) PR_Unlock(PRLock *lock);
PR_END_EXTERN_C
#endif /* prlock_h___ */
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