1 /* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements. See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License. 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_THREAD_MUTEX_H
18 #define APR_THREAD_MUTEX_H
21 * @file apr_thread_mutex.h
22 * @brief APR Thread Mutex Routines
26 #include "apr_errno.h"
30 #endif /* __cplusplus */
32 #if APR_HAS_THREADS || defined(DOXYGEN)
35 * @defgroup apr_thread_mutex Thread Mutex Routines
40 /** Opaque thread-local mutex structure */
41 typedef struct apr_thread_mutex_t apr_thread_mutex_t;
43 #define APR_THREAD_MUTEX_DEFAULT 0x0 /**< platform-optimal lock behavior */
44 #define APR_THREAD_MUTEX_NESTED 0x1 /**< enable nested (recursive) locks */
45 #define APR_THREAD_MUTEX_UNNESTED 0x2 /**< disable nested locks */
47 /* Delayed the include to avoid a circular reference */
48 #include "apr_pools.h"
51 * Create and initialize a mutex that can be used to synchronize threads.
52 * @param mutex the memory address where the newly created mutex will be
54 * @param flags Or'ed value of:
56 * APR_THREAD_MUTEX_DEFAULT platform-optimal lock behavior.
57 * APR_THREAD_MUTEX_NESTED enable nested (recursive) locks.
58 * APR_THREAD_MUTEX_UNNESTED disable nested locks (non-recursive).
60 * @param pool the pool from which to allocate the mutex.
61 * @warning Be cautious in using APR_THREAD_MUTEX_DEFAULT. While this is the
62 * most optimial mutex based on a given platform's performance charateristics,
63 * it will behave as either a nested or an unnested lock.
65 APR_DECLARE(apr_status_t) apr_thread_mutex_create(apr_thread_mutex_t **mutex,
69 * Acquire the lock for the given mutex. If the mutex is already locked,
70 * the current thread will be put to sleep until the lock becomes available.
71 * @param mutex the mutex on which to acquire the lock.
73 APR_DECLARE(apr_status_t) apr_thread_mutex_lock(apr_thread_mutex_t *mutex);
76 * Attempt to acquire the lock for the given mutex. If the mutex has already
77 * been acquired, the call returns immediately with APR_EBUSY. Note: it
78 * is important that the APR_STATUS_IS_EBUSY(s) macro be used to determine
79 * if the return value was APR_EBUSY, for portability reasons.
80 * @param mutex the mutex on which to attempt the lock acquiring.
82 APR_DECLARE(apr_status_t) apr_thread_mutex_trylock(apr_thread_mutex_t *mutex);
85 * Release the lock for the given mutex.
86 * @param mutex the mutex from which to release the lock.
88 APR_DECLARE(apr_status_t) apr_thread_mutex_unlock(apr_thread_mutex_t *mutex);
91 * Destroy the mutex and free the memory associated with the lock.
92 * @param mutex the mutex to destroy.
94 APR_DECLARE(apr_status_t) apr_thread_mutex_destroy(apr_thread_mutex_t *mutex);
97 * Get the pool used by this thread_mutex.
98 * @return apr_pool_t the pool
100 APR_POOL_DECLARE_ACCESSOR(thread_mutex);
102 #endif /* APR_HAS_THREADS */
110 #endif /* ! APR_THREAD_MUTEX_H */