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Diffstat (limited to 'mozilla/nsprpub/pr/include/prcvar.h')
-rw-r--r-- | mozilla/nsprpub/pr/include/prcvar.h | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/mozilla/nsprpub/pr/include/prcvar.h b/mozilla/nsprpub/pr/include/prcvar.h new file mode 100644 index 0000000..c668493 --- /dev/null +++ b/mozilla/nsprpub/pr/include/prcvar.h @@ -0,0 +1,126 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* ***** BEGIN LICENSE BLOCK ***** + * Version: MPL 1.1/GPL 2.0/LGPL 2.1 + * + * 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 the Initial Developer are Copyright (C) 1998-2000 + * the Initial Developer. All Rights Reserved. + * + * Contributor(s): + * + * Alternatively, the contents of this file may be used under the terms of + * either the GNU General Public License Version 2 or later (the "GPL"), or + * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), + * in which case the provisions of the GPL or the LGPL are applicable instead + * of those above. If you wish to allow use of your version of this file only + * under the terms of either the GPL or the LGPL, and not to allow others to + * use your version of this file under the terms of the MPL, indicate your + * decision by deleting the provisions above and replace them with the notice + * and other provisions required by the GPL or the LGPL. If you do not delete + * the provisions above, a recipient may use your version of this file under + * the terms of any one of the MPL, the GPL or the LGPL. + * + * ***** END LICENSE BLOCK ***** */ + +#ifndef prcvar_h___ +#define prcvar_h___ + +#include "prlock.h" +#include "prinrval.h" + +PR_BEGIN_EXTERN_C + +typedef struct PRCondVar PRCondVar; + +/* +** Create a new condition variable. +** +** "lock" is the lock used to protect the condition variable. +** +** Condition variables are synchronization objects that threads can use +** to wait for some condition to occur. +** +** This may fail if memory is tight or if some operating system resource +** is low. In such cases, a NULL will be returned. +*/ +NSPR_API(PRCondVar*) PR_NewCondVar(PRLock *lock); + +/* +** Destroy a condition variable. There must be no thread +** waiting on the condvar. The caller is responsible for guaranteeing +** that the condvar is no longer in use. +** +*/ +NSPR_API(void) PR_DestroyCondVar(PRCondVar *cvar); + +/* +** The thread that waits on a condition is blocked in a "waiting on +** condition" state until another thread notifies the condition or a +** caller specified amount of time expires. The lock associated with +** the condition variable will be released, which must have be held +** prior to the call to wait. +** +** Logically a notified thread is moved from the "waiting on condition" +** state and made "ready." When scheduled, it will attempt to reacquire +** the lock that it held when wait was called. +** +** The timeout has two well known values, PR_INTERVAL_NO_TIMEOUT and +** PR_INTERVAL_NO_WAIT. The former value requires that a condition be +** notified (or the thread interrupted) before it will resume from the +** wait. If the timeout has a value of PR_INTERVAL_NO_WAIT, the effect +** is to release the lock, possibly causing a rescheduling within the +** runtime, then immediately attempting to reacquire the lock and resume. +** +** Any other value for timeout will cause the thread to be rescheduled +** either due to explicit notification or an expired interval. The latter +** must be determined by treating time as one part of the monitored data +** being protected by the lock and tested explicitly for an expired +** interval. +** +** Returns PR_FAILURE if the caller has not locked the lock associated +** with the condition variable or the thread was interrupted (PR_Interrupt()). +** The particular reason can be extracted with PR_GetError(). +*/ +NSPR_API(PRStatus) PR_WaitCondVar(PRCondVar *cvar, PRIntervalTime timeout); + +/* +** Notify ONE thread that is currently waiting on 'cvar'. Which thread is +** dependent on the implementation of the runtime. Common sense would dictate +** that all threads waiting on a single condition have identical semantics, +** therefore which one gets notified is not significant. +** +** The calling thead must hold the lock that protects the condition, as +** well as the invariants that are tightly bound to the condition, when +** notify is called. +** +** Returns PR_FAILURE if the caller has not locked the lock associated +** with the condition variable. +*/ +NSPR_API(PRStatus) PR_NotifyCondVar(PRCondVar *cvar); + +/* +** Notify all of the threads waiting on the condition variable. The order +** that the threads are notified is indeterminant. The lock that protects +** the condition must be held. +** +** Returns PR_FAILURE if the caller has not locked the lock associated +** with the condition variable. +*/ +NSPR_API(PRStatus) PR_NotifyAllCondVar(PRCondVar *cvar); + +PR_END_EXTERN_C + +#endif /* prcvar_h___ */ |