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/* -*- 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___ */
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