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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: 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 "prtypes.h"
49:
50: PR_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: typedef struct PRLock PRLock;
64:
65: /**********************************************************************/
66: /****************************** FUNCTIONS *****************************/
67: /**********************************************************************/
68:
69: /***********************************************************************
70: ** FUNCTION: PR_NewLock
71: ** DESCRIPTION:
72: ** Returns a pointer to a newly created opaque lock object.
73: ** INPUTS: void
74: ** OUTPUTS: void
75: ** RETURN: PRLock*
76: ** If the lock can not be created because of resource constraints, NULL
77: ** is returned.
78: **
79: ***********************************************************************/
80: NSPR_API(PRLock*) PR_NewLock(void);
81:
82: /***********************************************************************
83: ** FUNCTION: PR_DestroyLock
84: ** DESCRIPTION:
85: ** Destroys a given opaque lock object.
86: ** INPUTS: PRLock *lock
87: ** Lock to be freed.
88: ** OUTPUTS: void
89: ** RETURN: None
90: ***********************************************************************/
91: NSPR_API(void) PR_DestroyLock(PRLock *lock);
92:
93: /***********************************************************************
94: ** FUNCTION: PR_Lock
95: ** DESCRIPTION:
96: ** Lock a lock.
97: ** INPUTS: PRLock *lock
98: ** Lock to locked.
99: ** OUTPUTS: void
100: ** RETURN: None
101: ***********************************************************************/
102: NSPR_API(void) PR_Lock(PRLock *lock);
103:
104: /***********************************************************************
105: ** FUNCTION: PR_Unlock
106: ** DESCRIPTION:
107: ** Unlock a lock. Unlocking an unlocked lock has undefined results.
108: ** INPUTS: PRLock *lock
109: ** Lock to unlocked.
110: ** OUTPUTS: void
111: ** RETURN: PR_STATUS
112: ** Returns PR_FAILURE if the caller does not own the lock.
113: ***********************************************************************/
114: NSPR_API(PRStatus) PR_Unlock(PRLock *lock);
115:
116: PR_END_EXTERN_C
117:
118: #endif /* prlock_h___ */
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