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comparison: nsprpub/pr/include/pripcsem.h
nsprpub/pr/include/pripcsem.h
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
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| -1:000000000000 | 0:b0e59a572354 |
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| 1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ | |
| 2 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 3 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 5 | |
| 6 /* | |
| 7 * File: pripcsem.h | |
| 8 * | |
| 9 * Description: named semaphores for interprocess | |
| 10 * synchronization | |
| 11 * | |
| 12 * Unrelated processes obtain access to a shared semaphore | |
| 13 * by specifying its name. | |
| 14 * | |
| 15 * Our goal is to support named semaphores on at least | |
| 16 * Unix and Win32 platforms. The implementation will use | |
| 17 * one of the three native semaphore APIs: POSIX, System V, | |
| 18 * and Win32. | |
| 19 * | |
| 20 * Because POSIX named semaphores have kernel persistence, | |
| 21 * we are forced to have a delete function in this API. | |
| 22 */ | |
| 23 | |
| 24 #ifndef pripcsem_h___ | |
| 25 #define pripcsem_h___ | |
| 26 | |
| 27 #include "prtypes.h" | |
| 28 #include "prio.h" | |
| 29 | |
| 30 PR_BEGIN_EXTERN_C | |
| 31 | |
| 32 /* | |
| 33 * PRSem is an opaque structure that represents a named | |
| 34 * semaphore. | |
| 35 */ | |
| 36 typedef struct PRSem PRSem; | |
| 37 | |
| 38 /* | |
| 39 * PR_OpenSemaphore -- | |
| 40 * | |
| 41 * Create or open a named semaphore with the specified name. | |
| 42 * A handle to the semaphore is returned. | |
| 43 * | |
| 44 * If the named semaphore doesn't exist and the PR_SEM_CREATE | |
| 45 * flag is specified, the named semaphore is created. The | |
| 46 * created semaphore needs to be removed from the system with | |
| 47 * a PR_DeleteSemaphore call. | |
| 48 * | |
| 49 * If PR_SEM_CREATE is specified, the third argument is the | |
| 50 * access permission bits of the new semaphore (same | |
| 51 * interpretation as the mode argument to PR_Open) and the | |
| 52 * fourth argument is the initial value of the new semaphore. | |
| 53 * If PR_SEM_CREATE is not specified, the third and fourth | |
| 54 * arguments are ignored. | |
| 55 */ | |
| 56 | |
| 57 #define PR_SEM_CREATE 0x1 /* create if not exist */ | |
| 58 #define PR_SEM_EXCL 0x2 /* fail if already exists */ | |
| 59 | |
| 60 NSPR_API(PRSem *) PR_OpenSemaphore( | |
| 61 const char *name, PRIntn flags, PRIntn mode, PRUintn value); | |
| 62 | |
| 63 /* | |
| 64 * PR_WaitSemaphore -- | |
| 65 * | |
| 66 * If the value of the semaphore is > 0, decrement the value and return. | |
| 67 * If the value is 0, sleep until the value becomes > 0, then decrement | |
| 68 * the value and return. | |
| 69 * | |
| 70 * The "test and decrement" operation is performed atomically. | |
| 71 */ | |
| 72 | |
| 73 NSPR_API(PRStatus) PR_WaitSemaphore(PRSem *sem); | |
| 74 | |
| 75 /* | |
| 76 * PR_PostSemaphore -- | |
| 77 * | |
| 78 * Increment the value of the named semaphore by 1. | |
| 79 */ | |
| 80 | |
| 81 NSPR_API(PRStatus) PR_PostSemaphore(PRSem *sem); | |
| 82 | |
| 83 /* | |
| 84 * PR_CloseSemaphore -- | |
| 85 * | |
| 86 * Close a named semaphore handle. | |
| 87 */ | |
| 88 | |
| 89 NSPR_API(PRStatus) PR_CloseSemaphore(PRSem *sem); | |
| 90 | |
| 91 /* | |
| 92 * PR_DeleteSemaphore -- | |
| 93 * | |
| 94 * Remove a named semaphore from the system. | |
| 95 */ | |
| 96 | |
| 97 NSPR_API(PRStatus) PR_DeleteSemaphore(const char *name); | |
| 98 | |
| 99 PR_END_EXTERN_C | |
| 100 | |
| 101 #endif /* pripcsem_h___ */ |
