/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* * The contents of this file are subject to the Mozilla Public * License Version 1.1 (the "License"); you may not use this file * except in compliance with the License. You may obtain a copy of * the License at http://www.mozilla.org/MPL/ * * Software distributed under the License is distributed on an "AS * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or * implied. See the License for the specific language governing * rights and limitations under the License. * * The Original Code is the Netscape Portable Runtime (NSPR). * * The Initial Developer of the Original Code is Netscape * Communications Corporation. Portions created by Netscape are * Copyright (C) 1998-2000 Netscape Communications Corporation. All * Rights Reserved. * * Contributor(s): * * Alternatively, the contents of this file may be used under the * terms of the GNU General Public License Version 2 or later (the * "GPL"), in which case the provisions of the GPL are applicable * instead of those above. If you wish to allow use of your * version of this file only under the terms of the GPL and not to * allow others to use your version of this file under the MPL, * indicate your decision by deleting the provisions above and * replace them with the notice and other provisions required by * the GPL. If you do not delete the provisions above, a recipient * may use your version of this file under either the MPL or the * GPL. */ /* ** File: prrwlock.h ** Description: API to basic reader-writer lock functions of NSPR. ** **/ #ifndef prrwlock_h___ #define prrwlock_h___ #include "prtypes.h" PR_BEGIN_EXTERN_C /* * PRRWLock -- * * The reader writer lock, PRRWLock, is an opaque object to the clients * of NSPR. All routines operate on a pointer to this opaque entity. */ typedef struct PRRWLock PRRWLock; #define PR_RWLOCK_RANK_NONE 0 /*********************************************************************** ** FUNCTION: PR_NewRWLock ** DESCRIPTION: ** Returns a pointer to a newly created reader-writer lock object. ** INPUTS: Lock rank ** Lock name ** OUTPUTS: void ** RETURN: PRRWLock* ** If the lock cannot be created because of resource constraints, NULL ** is returned. ** ***********************************************************************/ NSPR_API(PRRWLock*) PR_NewRWLock(PRUint32 lock_rank, const char *lock_name); /*********************************************************************** ** FUNCTION: PR_DestroyRWLock ** DESCRIPTION: ** Destroys a given RW lock object. ** INPUTS: PRRWLock *lock - Lock to be freed. ** OUTPUTS: void ** RETURN: None ***********************************************************************/ NSPR_API(void) PR_DestroyRWLock(PRRWLock *lock); /*********************************************************************** ** FUNCTION: PR_RWLock_Rlock ** DESCRIPTION: ** Apply a read lock (non-exclusive) on a RWLock ** INPUTS: PRRWLock *lock - Lock to be read-locked. ** OUTPUTS: void ** RETURN: None ***********************************************************************/ NSPR_API(void) PR_RWLock_Rlock(PRRWLock *lock); /*********************************************************************** ** FUNCTION: PR_RWLock_Wlock ** DESCRIPTION: ** Apply a write lock (exclusive) on a RWLock ** INPUTS: PRRWLock *lock - Lock to write-locked. ** OUTPUTS: void ** RETURN: None ***********************************************************************/ NSPR_API(void) PR_RWLock_Wlock(PRRWLock *lock); /*********************************************************************** ** FUNCTION: PR_RWLock_Unlock ** DESCRIPTION: ** Release a RW lock. Unlocking an unlocked lock has undefined results. ** INPUTS: PRRWLock *lock - Lock to unlocked. ** OUTPUTS: void ** RETURN: void ***********************************************************************/ NSPR_API(void) PR_RWLock_Unlock(PRRWLock *lock); PR_END_EXTERN_C #endif /* prrwlock_h___ */