pr/include/prrwlock.h
author gerv%gerv.net
Tue, 06 Mar 2012 13:14:34 +0000
changeset 4379 7950281c362aff29a2bbc80b22066c6ec7280b58
parent 3100 c110cccc95c167221408cd82c892eb9a8e17fe21
child 4834 6856b110d025599a243f0b0128c7f39572a9ead0
permissions -rw-r--r--
Bug 716564 - update licence to MPL 2. r=wtc.

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
** File:		prrwlock.h
** Description:	API to basic reader-writer lock functions of NSPR.
**
**/

#ifndef prrwlock_h___
#define prrwlock_h___

#include "prtypes.h"

PR_BEGIN_EXTERN_C

/*
 * PRRWLock --
 *
 *	The reader writer lock, PRRWLock, is an opaque object to the clients
 *	of NSPR.  All routines operate on a pointer to this opaque entity.
 */


typedef struct PRRWLock PRRWLock;

#define	PR_RWLOCK_RANK_NONE	0


/***********************************************************************
** FUNCTION:    PR_NewRWLock
** DESCRIPTION:
**  Returns a pointer to a newly created reader-writer lock object.
** INPUTS:      Lock rank
**				Lock name
** OUTPUTS:     void
** RETURN:      PRRWLock*
**   If the lock cannot be created because of resource constraints, NULL
**   is returned.
**  
***********************************************************************/
NSPR_API(PRRWLock*) PR_NewRWLock(PRUint32 lock_rank, const char *lock_name);

/***********************************************************************
** FUNCTION:    PR_DestroyRWLock
** DESCRIPTION:
**  Destroys a given RW lock object.
** INPUTS:      PRRWLock *lock - Lock to be freed.
** OUTPUTS:     void
** RETURN:      None
***********************************************************************/
NSPR_API(void) PR_DestroyRWLock(PRRWLock *lock);

/***********************************************************************
** FUNCTION:    PR_RWLock_Rlock
** DESCRIPTION:
**  Apply a read lock (non-exclusive) on a RWLock
** INPUTS:      PRRWLock *lock - Lock to be read-locked.
** OUTPUTS:     void
** RETURN:      None
***********************************************************************/
NSPR_API(void) PR_RWLock_Rlock(PRRWLock *lock);

/***********************************************************************
** FUNCTION:    PR_RWLock_Wlock
** DESCRIPTION:
**  Apply a write lock (exclusive) on a RWLock
** INPUTS:      PRRWLock *lock - Lock to write-locked.
** OUTPUTS:     void
** RETURN:      None
***********************************************************************/
NSPR_API(void) PR_RWLock_Wlock(PRRWLock *lock);

/***********************************************************************
** FUNCTION:    PR_RWLock_Unlock
** DESCRIPTION:
**  Release a RW lock. Unlocking an unlocked lock has undefined results.
** INPUTS:      PRRWLock *lock - Lock to unlocked.
** OUTPUTS:     void
** RETURN:      void
***********************************************************************/
NSPR_API(void) PR_RWLock_Unlock(PRRWLock *lock);

PR_END_EXTERN_C

#endif /* prrwlock_h___ */