1/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2/*
3 * The contents of this file are subject to the Mozilla Public
4 * License Version 1.1 (the "License"); you may not use this file
5 * except in compliance with the License. You may obtain a copy of
6 * the License at http://www.mozilla.org/MPL/
7 *
8 * Software distributed under the License is distributed on an "AS
9 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
10 * implied. See the License for the specific language governing
11 * rights and limitations under the License.
12 *
13 * The Original Code is the Netscape Portable Runtime (NSPR).
14 *
15 * The Initial Developer of the Original Code is Netscape
16 * Communications Corporation.  Portions created by Netscape are
17 * Copyright (C) 1998-2000 Netscape Communications Corporation.  All
18 * Rights Reserved.
19 *
20 * Contributor(s):
21 *
22 * Alternatively, the contents of this file may be used under the
23 * terms of the GNU General Public License Version 2 or later (the
24 * "GPL"), in which case the provisions of the GPL are applicable
25 * instead of those above.  If you wish to allow use of your
26 * version of this file only under the terms of the GPL and not to
27 * allow others to use your version of this file under the MPL,
28 * indicate your decision by deleting the provisions above and
29 * replace them with the notice and other provisions required by
30 * the GPL.  If you do not delete the provisions above, a recipient
31 * may use your version of this file under either the MPL or the
32 * GPL.
33 */
34
35/*
36** File:		prlock.h
37** Description:	API to basic locking functions of NSPR.
38**
39**
40** NSPR provides basic locking mechanisms for thread synchronization.  Locks
41** are lightweight resource contention controls that prevent multiple threads
42** from accessing something (code/data) simultaneously.
43**/
44
45#ifndef prlock_h___
46#define prlock_h___
47
48#include <security_asn1/prtypes.h>
49
50PR_BEGIN_EXTERN_C
51
52/**********************************************************************/
53/************************* TYPES AND CONSTANTS ************************/
54/**********************************************************************/
55
56/*
57 * PRLock --
58 *
59 *     NSPR represents the lock as an opaque entity to the client of the
60 *	   API.  All routines operate on a pointer to this opaque entity.
61 */
62
63#if defined(__APPLE_) & defined(__GNUC__)
64/* dmitch - actually a pthread_mutex_t */
65typedef void PRLock;
66#else
67typedef struct PRLock PRLock;
68#endif
69
70/**********************************************************************/
71/****************************** FUNCTIONS *****************************/
72/**********************************************************************/
73
74/***********************************************************************
75** FUNCTION:    PR_NewLock
76** DESCRIPTION:
77**  Returns a pointer to a newly created opaque lock object.
78** INPUTS:      void
79** OUTPUTS:     void
80** RETURN:      PRLock*
81**   If the lock can not be created because of resource constraints, NULL
82**   is returned.
83**
84***********************************************************************/
85NSPR_API(PRLock*) PR_NewLock(void);
86
87/***********************************************************************
88** FUNCTION:    PR_DestroyLock
89** DESCRIPTION:
90**  Destroys a given opaque lock object.
91** INPUTS:      PRLock *lock
92**              Lock to be freed.
93** OUTPUTS:     void
94** RETURN:      None
95***********************************************************************/
96NSPR_API(void) PR_DestroyLock(PRLock *lock);
97
98/***********************************************************************
99** FUNCTION:    PR_Lock
100** DESCRIPTION:
101**  Lock a lock.
102** INPUTS:      PRLock *lock
103**              Lock to locked.
104** OUTPUTS:     void
105** RETURN:      None
106***********************************************************************/
107NSPR_API(void) PR_Lock(PRLock *lock);
108
109/***********************************************************************
110** FUNCTION:    PR_Unlock
111** DESCRIPTION:
112**  Unlock a lock.  Unlocking an unlocked lock has undefined results.
113** INPUTS:      PRLock *lock
114**              Lock to unlocked.
115** OUTPUTS:     void
116** RETURN:      PR_STATUS
117**              Returns PR_FAILURE if the caller does not own the lock.
118***********************************************************************/
119NSPR_API(PRStatus) PR_Unlock(PRLock *lock);
120
121PR_END_EXTERN_C
122
123#endif /* prlock_h___ */
124