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author | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
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committer | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
commit | 5f8de423f190bbb79a62f804151bc24824fa32d8 (patch) | |
tree | 10027f336435511475e392454359edea8e25895d /nsprpub/pr/include/pripcsem.h | |
parent | 49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff) | |
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Add m-esr52 at 52.6.0
Diffstat (limited to 'nsprpub/pr/include/pripcsem.h')
-rw-r--r-- | nsprpub/pr/include/pripcsem.h | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/nsprpub/pr/include/pripcsem.h b/nsprpub/pr/include/pripcsem.h new file mode 100644 index 000000000..f5a524da1 --- /dev/null +++ b/nsprpub/pr/include/pripcsem.h @@ -0,0 +1,101 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +/* + * 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___ */ |