122 lines
4.4 KiB
C
122 lines
4.4 KiB
C
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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is the Netscape Portable Runtime (NSPR).
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*
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* The Initial Developer of the Original Code is
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* Netscape Communications Corporation.
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* Portions created by the Initial Developer are Copyright (C) 1998-2000
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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/*
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** File: prlock.h
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** Description: API to basic locking functions of NSPR.
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**
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**
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** NSPR provides basic locking mechanisms for thread synchronization. Locks
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** are lightweight resource contention controls that prevent multiple threads
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** from accessing something (code/data) simultaneously.
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**/
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#ifndef prlock_h___
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#define prlock_h___
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#include "prtypes.h"
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PR_BEGIN_EXTERN_C
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/**********************************************************************/
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/************************* TYPES AND CONSTANTS ************************/
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/**********************************************************************/
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/*
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* PRLock --
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*
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* NSPR represents the lock as an opaque entity to the client of the
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* API. All routines operate on a pointer to this opaque entity.
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*/
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typedef struct PRLock PRLock;
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/**********************************************************************/
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/****************************** FUNCTIONS *****************************/
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/**********************************************************************/
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/***********************************************************************
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** FUNCTION: PR_NewLock
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** DESCRIPTION:
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** Returns a pointer to a newly created opaque lock object.
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** INPUTS: void
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** OUTPUTS: void
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** RETURN: PRLock*
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** If the lock can not be created because of resource constraints, NULL
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** is returned.
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**
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***********************************************************************/
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NSPR_API(PRLock*) PR_NewLock(void);
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/***********************************************************************
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** FUNCTION: PR_DestroyLock
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** DESCRIPTION:
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** Destroys a given opaque lock object.
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** INPUTS: PRLock *lock
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** Lock to be freed.
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** OUTPUTS: void
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** RETURN: None
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***********************************************************************/
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NSPR_API(void) PR_DestroyLock(PRLock *lock);
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/***********************************************************************
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** FUNCTION: PR_Lock
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** DESCRIPTION:
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** Lock a lock.
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** INPUTS: PRLock *lock
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** Lock to locked.
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** OUTPUTS: void
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** RETURN: None
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***********************************************************************/
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NSPR_API(void) PR_Lock(PRLock *lock);
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/***********************************************************************
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** FUNCTION: PR_Unlock
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** DESCRIPTION:
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** Unlock a lock. Unlocking an unlocked lock has undefined results.
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** INPUTS: PRLock *lock
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** Lock to unlocked.
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** OUTPUTS: void
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** RETURN: PR_STATUS
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** Returns PR_FAILURE if the caller does not own the lock.
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***********************************************************************/
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NSPR_API(PRStatus) PR_Unlock(PRLock *lock);
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PR_END_EXTERN_C
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#endif /* prlock_h___ */
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