third_party/npapi/npspy/extern/nspr/prlock.h

   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
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   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.
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  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
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  31  * may use your version of this file under either the MPL or the
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  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___ */