pripcsem.h
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- /* -*- 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) 1999-2000
- * 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
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- * 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
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- * 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 ***** */
- /*
- * File: pripcsem.h
- *
- * Description: named semaphores for interprocess
- * synchronization
- *
- * Unrelated processes obtain access to a shared semaphore
- * by specifying its name.
- *
- * Our goal is to support named semaphores on at least
- * Unix and Win32 platforms. The implementation will use
- * one of the three native semaphore APIs: POSIX, System V,
- * and Win32.
- *
- * Because POSIX named semaphores have kernel persistence,
- * we are forced to have a delete function in this API.
- */
- #ifndef pripcsem_h___
- #define pripcsem_h___
- #include "prtypes.h"
- #include "prio.h"
- PR_BEGIN_EXTERN_C
- /*
- * PRSem is an opaque structure that represents a named
- * semaphore.
- */
- typedef struct PRSem PRSem;
- /*
- * PR_OpenSemaphore --
- *
- * Create or open a named semaphore with the specified name.
- * A handle to the semaphore is returned.
- *
- * If the named semaphore doesn't exist and the PR_SEM_CREATE
- * flag is specified, the named semaphore is created. The
- * created semaphore needs to be removed from the system with
- * a PR_DeleteSemaphore call.
- *
- * If PR_SEM_CREATE is specified, the third argument is the
- * access permission bits of the new semaphore (same
- * interpretation as the mode argument to PR_Open) and the
- * fourth argument is the initial value of the new semaphore.
- * If PR_SEM_CREATE is not specified, the third and fourth
- * arguments are ignored.
- */
- #define PR_SEM_CREATE 0x1 /* create if not exist */
- #define PR_SEM_EXCL 0x2 /* fail if already exists */
- NSPR_API(PRSem *) PR_OpenSemaphore(
- const char *name, PRIntn flags, PRIntn mode, PRUintn value);
- /*
- * PR_WaitSemaphore --
- *
- * If the value of the semaphore is > 0, decrement the value and return.
- * If the value is 0, sleep until the value becomes > 0, then decrement
- * the value and return.
- *
- * The "test and decrement" operation is performed atomically.
- */
- NSPR_API(PRStatus) PR_WaitSemaphore(PRSem *sem);
- /*
- * PR_PostSemaphore --
- *
- * Increment the value of the named semaphore by 1.
- */
- NSPR_API(PRStatus) PR_PostSemaphore(PRSem *sem);
- /*
- * PR_CloseSemaphore --
- *
- * Close a named semaphore handle.
- */
- NSPR_API(PRStatus) PR_CloseSemaphore(PRSem *sem);
- /*
- * PR_DeleteSemaphore --
- *
- * Remove a named semaphore from the system.
- */
- NSPR_API(PRStatus) PR_DeleteSemaphore(const char *name);
- PR_END_EXTERN_C
- #endif /* pripcsem_h___ */