gecko-dev/nsprpub/pr/include/prlock.h
1999-04-21 21:40:44 +00:00

103 lines
3.4 KiB
C

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/*
* The contents of this file are subject to the Netscape Public License
* Version 1.1 (the "NPL"); you may not use this file except in
* compliance with the NPL. You may obtain a copy of the NPL at
* http://www.mozilla.org/NPL/
*
* Software distributed under the NPL is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
* for the specific language governing rights and limitations under the
* NPL.
*
* The Initial Developer of this code under the NPL is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All Rights
* Reserved.
*/
/*
** 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.
**
***********************************************************************/
PR_EXTERN(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
***********************************************************************/
PR_EXTERN(void) PR_DestroyLock(PRLock *lock);
/***********************************************************************
** FUNCTION: PR_Lock
** DESCRIPTION:
** Lock a lock.
** INPUTS: PRLock *lock
** Lock to locked.
** OUTPUTS: void
** RETURN: None
***********************************************************************/
PR_EXTERN(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.
***********************************************************************/
PR_EXTERN(PRStatus) PR_Unlock(PRLock *lock);
PR_END_EXTERN_C
#endif /* prlock_h___ */