1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/nsprpub/pr/include/pripcsem.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,101 @@
1.4 +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +/*
1.10 + * File: pripcsem.h
1.11 + *
1.12 + * Description: named semaphores for interprocess
1.13 + * synchronization
1.14 + *
1.15 + * Unrelated processes obtain access to a shared semaphore
1.16 + * by specifying its name.
1.17 + *
1.18 + * Our goal is to support named semaphores on at least
1.19 + * Unix and Win32 platforms. The implementation will use
1.20 + * one of the three native semaphore APIs: POSIX, System V,
1.21 + * and Win32.
1.22 + *
1.23 + * Because POSIX named semaphores have kernel persistence,
1.24 + * we are forced to have a delete function in this API.
1.25 + */
1.26 +
1.27 +#ifndef pripcsem_h___
1.28 +#define pripcsem_h___
1.29 +
1.30 +#include "prtypes.h"
1.31 +#include "prio.h"
1.32 +
1.33 +PR_BEGIN_EXTERN_C
1.34 +
1.35 +/*
1.36 + * PRSem is an opaque structure that represents a named
1.37 + * semaphore.
1.38 + */
1.39 +typedef struct PRSem PRSem;
1.40 +
1.41 +/*
1.42 + * PR_OpenSemaphore --
1.43 + *
1.44 + * Create or open a named semaphore with the specified name.
1.45 + * A handle to the semaphore is returned.
1.46 + *
1.47 + * If the named semaphore doesn't exist and the PR_SEM_CREATE
1.48 + * flag is specified, the named semaphore is created. The
1.49 + * created semaphore needs to be removed from the system with
1.50 + * a PR_DeleteSemaphore call.
1.51 + *
1.52 + * If PR_SEM_CREATE is specified, the third argument is the
1.53 + * access permission bits of the new semaphore (same
1.54 + * interpretation as the mode argument to PR_Open) and the
1.55 + * fourth argument is the initial value of the new semaphore.
1.56 + * If PR_SEM_CREATE is not specified, the third and fourth
1.57 + * arguments are ignored.
1.58 + */
1.59 +
1.60 +#define PR_SEM_CREATE 0x1 /* create if not exist */
1.61 +#define PR_SEM_EXCL 0x2 /* fail if already exists */
1.62 +
1.63 +NSPR_API(PRSem *) PR_OpenSemaphore(
1.64 + const char *name, PRIntn flags, PRIntn mode, PRUintn value);
1.65 +
1.66 +/*
1.67 + * PR_WaitSemaphore --
1.68 + *
1.69 + * If the value of the semaphore is > 0, decrement the value and return.
1.70 + * If the value is 0, sleep until the value becomes > 0, then decrement
1.71 + * the value and return.
1.72 + *
1.73 + * The "test and decrement" operation is performed atomically.
1.74 + */
1.75 +
1.76 +NSPR_API(PRStatus) PR_WaitSemaphore(PRSem *sem);
1.77 +
1.78 +/*
1.79 + * PR_PostSemaphore --
1.80 + *
1.81 + * Increment the value of the named semaphore by 1.
1.82 + */
1.83 +
1.84 +NSPR_API(PRStatus) PR_PostSemaphore(PRSem *sem);
1.85 +
1.86 +/*
1.87 + * PR_CloseSemaphore --
1.88 + *
1.89 + * Close a named semaphore handle.
1.90 + */
1.91 +
1.92 +NSPR_API(PRStatus) PR_CloseSemaphore(PRSem *sem);
1.93 +
1.94 +/*
1.95 + * PR_DeleteSemaphore --
1.96 + *
1.97 + * Remove a named semaphore from the system.
1.98 + */
1.99 +
1.100 +NSPR_API(PRStatus) PR_DeleteSemaphore(const char *name);
1.101 +
1.102 +PR_END_EXTERN_C
1.103 +
1.104 +#endif /* pripcsem_h___ */
