/* -*- 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. */ #ifndef prsem_h___ #define prsem_h___ /* ** API for counting semaphores. Semaphores are counting synchronizing ** variables based on a lock and a condition variable. They are lightweight ** contention control for a given count of resources. */ #include "prtypes.h" PR_BEGIN_EXTERN_C typedef struct PRSemaphore PRSemaphore; /* ** Create a new semaphore object. */ NSPR_API(PRSemaphore*) PR_NewSem(PRUintn value); /* ** Destroy the given semaphore object. ** */ NSPR_API(void) PR_DestroySem(PRSemaphore *sem); /* ** Wait on a Semaphore. ** ** This routine allows a calling thread to wait or proceed depending upon the ** state of the semahore sem. The thread can proceed only if the counter value ** of the semaphore sem is currently greater than 0. If the value of semaphore ** sem is positive, it is decremented by one and the routine returns immediately ** allowing the calling thread to continue. If the value of semaphore sem is 0, ** the calling thread blocks awaiting the semaphore to be released by another ** thread. ** ** This routine can return PR_PENDING_INTERRUPT if the waiting thread ** has been interrupted. */ NSPR_API(PRStatus) PR_WaitSem(PRSemaphore *sem); /* ** This routine increments the counter value of the semaphore. If other threads ** are blocked for the semaphore, then the scheduler will determine which ONE ** thread will be unblocked. */ NSPR_API(void) PR_PostSem(PRSemaphore *sem); /* ** Returns the value of the semaphore referenced by sem without affecting ** the state of the semaphore. The value represents the semaphore vaule F** at the time of the call, but may not be the actual value when the ** caller inspects it. */ NSPR_API(PRUintn) PR_GetValueSem(PRSemaphore *sem); PR_END_EXTERN_C #endif /* prsem_h___ */