1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
|
/* Copyright 2000-2005 The Apache Software Foundation or its licensors, as
* applicable.
*
* Licensed 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_COND_H
#define APR_THREAD_COND_H
/**
* @file apr_thread_cond.h
* @brief APR Condition Variable Routines
*/
#include "apr.h"
#include "apr_pools.h"
#include "apr_errno.h"
#include "apr_time.h"
#include "apr_thread_mutex.h"
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
#if APR_HAS_THREADS || defined(DOXYGEN)
/**
* @defgroup apr_thread_cond Condition Variable Routines
* @ingroup APR
* @{
*/
/** Opaque structure for thread condition variables */
typedef struct apr_thread_cond_t apr_thread_cond_t;
/**
* Note: destroying a condition variable (or likewise, destroying or
* clearing the pool from which a condition variable was allocated) if
* any threads are blocked waiting on it gives undefined results.
*/
/**
* Create and initialize a condition variable that can be used to signal
* and schedule threads in a single process.
* @param cond the memory address where the newly created condition variable
* will be stored.
* @param pool the pool from which to allocate the mutex.
*/
APR_DECLARE(apr_status_t) apr_thread_cond_create(apr_thread_cond_t **cond,
apr_pool_t *pool);
/**
* Put the active calling thread to sleep until signaled to wake up. Each
* condition variable must be associated with a mutex, and that mutex must
* be locked before calling this function, or the behavior will be
* undefined. As the calling thread is put to sleep, the given mutex
* will be simultaneously released; and as this thread wakes up the lock
* is again simultaneously acquired.
* @param cond the condition variable on which to block.
* @param mutex the mutex that must be locked upon entering this function,
* is released while the thread is asleep, and is again acquired before
* returning from this function.
*/
APR_DECLARE(apr_status_t) apr_thread_cond_wait(apr_thread_cond_t *cond,
apr_thread_mutex_t *mutex);
/**
* Put the active calling thread to sleep until signaled to wake up or
* the timeout is reached. Each condition variable must be associated
* with a mutex, and that mutex must be locked before calling this
* function, or the behavior will be undefined. As the calling thread
* is put to sleep, the given mutex will be simultaneously released;
* and as this thread wakes up the lock is again simultaneously acquired.
* @param cond the condition variable on which to block.
* @param mutex the mutex that must be locked upon entering this function,
* is released while the thread is asleep, and is again acquired before
* returning from this function.
* @param timeout The amount of time in microseconds to wait. This is
* a maximum, not a minimum. If the condition is signaled, we
* will wake up before this time, otherwise the error APR_TIMEUP
* is returned.
*/
APR_DECLARE(apr_status_t) apr_thread_cond_timedwait(apr_thread_cond_t *cond,
apr_thread_mutex_t *mutex,
apr_interval_time_t timeout);
/**
* Signals a single thread, if one exists, that is blocking on the given
* condition variable. That thread is then scheduled to wake up and acquire
* the associated mutex. Although it is not required, if predictable scheduling
* is desired, that mutex must be locked while calling this function.
* @param cond the condition variable on which to produce the signal.
*/
APR_DECLARE(apr_status_t) apr_thread_cond_signal(apr_thread_cond_t *cond);
/**
* Signals all threads blocking on the given condition variable.
* Each thread that was signaled is then scheduled to wake up and acquire
* the associated mutex. This will happen in a serialized manner.
* @param cond the condition variable on which to produce the broadcast.
*/
APR_DECLARE(apr_status_t) apr_thread_cond_broadcast(apr_thread_cond_t *cond);
/**
* Destroy the condition variable and free the associated memory.
* @param cond the condition variable to destroy.
*/
APR_DECLARE(apr_status_t) apr_thread_cond_destroy(apr_thread_cond_t *cond);
/**
* Get the pool used by this thread_cond.
* @return apr_pool_t the pool
*/
APR_POOL_DECLARE_ACCESSOR(thread_cond);
#endif /* APR_HAS_THREADS */
/** @} */
#ifdef __cplusplus
}
#endif
#endif /* ! APR_THREAD_COND_H */
|
