1
/* Copyright 2000-2005 The Apache Software Foundation or its licensors, as
4
* Licensed under the Apache License, Version 2.0 (the "License");
5
* you may not use this file except in compliance with the License.
6
* You may obtain a copy of the License at
8
* http://www.apache.org/licenses/LICENSE-2.0
10
* Unless required by applicable law or agreed to in writing, software
11
* distributed under the License is distributed on an "AS IS" BASIS,
12
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13
* See the License for the specific language governing permissions and
14
* limitations under the License.
17
#ifndef APR_GLOBAL_MUTEX_H
18
#define APR_GLOBAL_MUTEX_H
21
* @file apr_global_mutex.h
22
* @brief APR Global Locking Routines
26
#include "apr_proc_mutex.h" /* only for apr_lockmech_e */
27
#include "apr_pools.h"
28
#include "apr_errno.h"
29
#if APR_PROC_MUTEX_IS_GLOBAL
30
#include "apr_proc_mutex.h"
35
#endif /* __cplusplus */
38
* @defgroup APR_GlobalMutex Global Locking Routines
43
#if !APR_PROC_MUTEX_IS_GLOBAL || defined(DOXYGEN)
45
/** Opaque global mutex structure. */
46
typedef struct apr_global_mutex_t apr_global_mutex_t;
48
/* Function definitions */
51
* Create and initialize a mutex that can be used to synchronize both
52
* processes and threads. Note: There is considerable overhead in using
53
* this API if only cross-process or cross-thread mutual exclusion is
54
* required. See apr_proc_mutex.h and apr_thread_mutex.h for more
55
* specialized lock routines.
56
* @param mutex the memory address where the newly created mutex will be
58
* @param fname A file name to use if the lock mechanism requires one. This
59
* argument should always be provided. The lock code itself will
60
* determine if it should be used.
61
* @param mech The mechanism to use for the interprocess lock, if any; one of
67
* APR_LOCK_PROC_PTHREAD
68
* APR_LOCK_DEFAULT pick the default mechanism for the platform
70
* @param pool the pool from which to allocate the mutex.
71
* @warning Check APR_HAS_foo_SERIALIZE defines to see if the platform supports
72
* APR_LOCK_foo. Only APR_LOCK_DEFAULT is portable.
74
APR_DECLARE(apr_status_t) apr_global_mutex_create(apr_global_mutex_t **mutex,
80
* Re-open a mutex in a child process.
81
* @param mutex The newly re-opened mutex structure.
82
* @param fname A file name to use if the mutex mechanism requires one. This
83
* argument should always be provided. The mutex code itself will
84
* determine if it should be used. This filename should be the
85
* same one that was passed to apr_global_mutex_create().
86
* @param pool The pool to operate on.
87
* @remark This function must be called to maintain portability, even
88
* if the underlying lock mechanism does not require it.
90
APR_DECLARE(apr_status_t) apr_global_mutex_child_init(
91
apr_global_mutex_t **mutex,
96
* Acquire the lock for the given mutex. If the mutex is already locked,
97
* the current thread will be put to sleep until the lock becomes available.
98
* @param mutex the mutex on which to acquire the lock.
100
APR_DECLARE(apr_status_t) apr_global_mutex_lock(apr_global_mutex_t *mutex);
103
* Attempt to acquire the lock for the given mutex. If the mutex has already
104
* been acquired, the call returns immediately with APR_EBUSY. Note: it
105
* is important that the APR_STATUS_IS_EBUSY(s) macro be used to determine
106
* if the return value was APR_EBUSY, for portability reasons.
107
* @param mutex the mutex on which to attempt the lock acquiring.
109
APR_DECLARE(apr_status_t) apr_global_mutex_trylock(apr_global_mutex_t *mutex);
112
* Release the lock for the given mutex.
113
* @param mutex the mutex from which to release the lock.
115
APR_DECLARE(apr_status_t) apr_global_mutex_unlock(apr_global_mutex_t *mutex);
118
* Destroy the mutex and free the memory associated with the lock.
119
* @param mutex the mutex to destroy.
121
APR_DECLARE(apr_status_t) apr_global_mutex_destroy(apr_global_mutex_t *mutex);
124
* Get the pool used by this global_mutex.
125
* @return apr_pool_t the pool
127
APR_POOL_DECLARE_ACCESSOR(global_mutex);
129
#else /* APR_PROC_MUTEX_IS_GLOBAL */
131
/* Some platforms [e.g. Win32] have cross process locks that are truly
132
* global locks, since there isn't the concept of cross-process locks.
133
* Define these platforms in terms of an apr_proc_mutex_t.
136
#define apr_global_mutex_t apr_proc_mutex_t
137
#define apr_global_mutex_create apr_proc_mutex_create
138
#define apr_global_mutex_child_init apr_proc_mutex_child_init
139
#define apr_global_mutex_lock apr_proc_mutex_lock
140
#define apr_global_mutex_trylock apr_proc_mutex_trylock
141
#define apr_global_mutex_unlock apr_proc_mutex_unlock
142
#define apr_global_mutex_destroy apr_proc_mutex_destroy
143
#define apr_global_mutex_pool_get apr_proc_mutex_pool_get
153
#endif /* ndef APR_GLOBAL_MUTEX_H */