/* Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifndef APR_THREAD_MUTEX_H #define APR_THREAD_MUTEX_H /** * @file apr_thread_mutex.h * @brief APR Thread Mutex Routines */ #include "apr.h" #include "apr_errno.h" #ifdef __cplusplus extern "C" { #endif /* __cplusplus */ #if APR_HAS_THREADS || defined(DOXYGEN) /** * @defgroup apr_thread_mutex Thread Mutex Routines * @ingroup APR * @{ */ /** Opaque thread-local mutex structure */ typedef struct apr_thread_mutex_t apr_thread_mutex_t; #define APR_THREAD_MUTEX_DEFAULT 0x0 /**< platform-optimal lock behavior */ #define APR_THREAD_MUTEX_NESTED 0x1 /**< enable nested (recursive) locks */ #define APR_THREAD_MUTEX_UNNESTED 0x2 /**< disable nested locks */ /* Delayed the include to avoid a circular reference */ #include "apr_pools.h" /** * Create and initialize a mutex that can be used to synchronize threads. * @param mutex the memory address where the newly created mutex will be * stored. * @param flags Or'ed value of: * <PRE> * APR_THREAD_MUTEX_DEFAULT platform-optimal lock behavior. * APR_THREAD_MUTEX_NESTED enable nested (recursive) locks. * APR_THREAD_MUTEX_UNNESTED disable nested locks (non-recursive). * </PRE> * @param pool the pool from which to allocate the mutex. * @warning Be cautious in using APR_THREAD_MUTEX_DEFAULT. While this is the * most optimial mutex based on a given platform's performance charateristics, * it will behave as either a nested or an unnested lock. */ APR_DECLARE(apr_status_t) apr_thread_mutex_create(apr_thread_mutex_t **mutex, unsigned int flags, apr_pool_t *pool); /** * Acquire the lock for the given mutex. If the mutex is already locked, * the current thread will be put to sleep until the lock becomes available. * @param mutex the mutex on which to acquire the lock. */ APR_DECLARE(apr_status_t) apr_thread_mutex_lock(apr_thread_mutex_t *mutex); /** * Attempt to acquire the lock for the given mutex. If the mutex has already * been acquired, the call returns immediately with APR_EBUSY. Note: it * is important that the APR_STATUS_IS_EBUSY(s) macro be used to determine * if the return value was APR_EBUSY, for portability reasons. * @param mutex the mutex on which to attempt the lock acquiring. */ APR_DECLARE(apr_status_t) apr_thread_mutex_trylock(apr_thread_mutex_t *mutex); /** * Release the lock for the given mutex. * @param mutex the mutex from which to release the lock. */ APR_DECLARE(apr_status_t) apr_thread_mutex_unlock(apr_thread_mutex_t *mutex); /** * Destroy the mutex and free the memory associated with the lock. * @param mutex the mutex to destroy. */ APR_DECLARE(apr_status_t) apr_thread_mutex_destroy(apr_thread_mutex_t *mutex); /** * Get the pool used by this thread_mutex. * @return apr_pool_t the pool */ APR_POOL_DECLARE_ACCESSOR(thread_mutex); #endif /* APR_HAS_THREADS */ /** @} */ #ifdef __cplusplus } #endif #endif /* ! APR_THREAD_MUTEX_H */