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1.1 root 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: prrwlock.h
37: ** Description: API to basic reader-writer lock functions of NSPR.
38: **
39: **/
40:
41: #ifndef prrwlock_h___
42: #define prrwlock_h___
43:
44: #include "prtypes.h"
45:
46: PR_BEGIN_EXTERN_C
47:
48: /*
49: * PRRWLock --
50: *
51: * The reader writer lock, PRRWLock, is an opaque object to the clients
52: * of NSPR. All routines operate on a pointer to this opaque entity.
53: */
54:
55:
56: typedef struct PRRWLock PRRWLock;
57:
58: #define PR_RWLOCK_RANK_NONE 0
59:
60:
61: /***********************************************************************
62: ** FUNCTION: PR_NewRWLock
63: ** DESCRIPTION:
64: ** Returns a pointer to a newly created reader-writer lock object.
65: ** INPUTS: Lock rank
66: ** Lock name
67: ** OUTPUTS: void
68: ** RETURN: PRRWLock*
69: ** If the lock cannot be created because of resource constraints, NULL
70: ** is returned.
71: **
72: ***********************************************************************/
73: NSPR_API(PRRWLock*) PR_NewRWLock(PRUint32 lock_rank, const char *lock_name);
74:
75: /***********************************************************************
76: ** FUNCTION: PR_DestroyRWLock
77: ** DESCRIPTION:
78: ** Destroys a given RW lock object.
79: ** INPUTS: PRRWLock *lock - Lock to be freed.
80: ** OUTPUTS: void
81: ** RETURN: None
82: ***********************************************************************/
83: NSPR_API(void) PR_DestroyRWLock(PRRWLock *lock);
84:
85: /***********************************************************************
86: ** FUNCTION: PR_RWLock_Rlock
87: ** DESCRIPTION:
88: ** Apply a read lock (non-exclusive) on a RWLock
89: ** INPUTS: PRRWLock *lock - Lock to be read-locked.
90: ** OUTPUTS: void
91: ** RETURN: None
92: ***********************************************************************/
93: NSPR_API(void) PR_RWLock_Rlock(PRRWLock *lock);
94:
95: /***********************************************************************
96: ** FUNCTION: PR_RWLock_Wlock
97: ** DESCRIPTION:
98: ** Apply a write lock (exclusive) on a RWLock
99: ** INPUTS: PRRWLock *lock - Lock to write-locked.
100: ** OUTPUTS: void
101: ** RETURN: None
102: ***********************************************************************/
103: NSPR_API(void) PR_RWLock_Wlock(PRRWLock *lock);
104:
105: /***********************************************************************
106: ** FUNCTION: PR_RWLock_Unlock
107: ** DESCRIPTION:
108: ** Release a RW lock. Unlocking an unlocked lock has undefined results.
109: ** INPUTS: PRRWLock *lock - Lock to unlocked.
110: ** OUTPUTS: void
111: ** RETURN: void
112: ***********************************************************************/
113: NSPR_API(void) PR_RWLock_Unlock(PRRWLock *lock);
114:
115: PR_END_EXTERN_C
116:
117: #endif /* prrwlock_h___ */
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