/* -*- 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: prlock.h ** Description: API to basic locking functions of NSPR. ** ** ** NSPR provides basic locking mechanisms for thread synchronization. Locks ** are lightweight resource contention controls that prevent multiple threads ** from accessing something (code/data) simultaneously. **/ #ifndef prlock_h___ #define prlock_h___ #include "prtypes.h" PR_BEGIN_EXTERN_C /**********************************************************************/ /************************* TYPES AND CONSTANTS ************************/ /**********************************************************************/ /* * PRLock -- * * NSPR represents the lock as an opaque entity to the client of the * API. All routines operate on a pointer to this opaque entity. */ typedef struct PRLock PRLock; /**********************************************************************/ /****************************** FUNCTIONS *****************************/ /**********************************************************************/ /*********************************************************************** ** FUNCTION: PR_NewLock ** DESCRIPTION: ** Returns a pointer to a newly created opaque lock object. ** INPUTS: void ** OUTPUTS: void ** RETURN: PRLock* ** If the lock can not be created because of resource constraints, NULL ** is returned. ** ***********************************************************************/ NSPR_API(PRLock*) PR_NewLock(void); /*********************************************************************** ** FUNCTION: PR_DestroyLock ** DESCRIPTION: ** Destroys a given opaque lock object. ** INPUTS: PRLock *lock ** Lock to be freed. ** OUTPUTS: void ** RETURN: None ***********************************************************************/ NSPR_API(void) PR_DestroyLock(PRLock *lock); /*********************************************************************** ** FUNCTION: PR_Lock ** DESCRIPTION: ** Lock a lock. ** INPUTS: PRLock *lock ** Lock to locked. ** OUTPUTS: void ** RETURN: None ***********************************************************************/ NSPR_API(void) PR_Lock(PRLock *lock); /*********************************************************************** ** FUNCTION: PR_Unlock ** DESCRIPTION: ** Unlock a lock. Unlocking an unlocked lock has undefined results. ** INPUTS: PRLock *lock ** Lock to unlocked. ** OUTPUTS: void ** RETURN: PR_STATUS ** Returns PR_FAILURE if the caller does not own the lock. ***********************************************************************/ NSPR_API(PRStatus) PR_Unlock(PRLock *lock); PR_END_EXTERN_C #endif /* prlock_h___ */