urcu-bp: Update fork() handling
[urcu.git] / urcu-bp.h
1 #ifndef _URCU_BP_H
2 #define _URCU_BP_H
3
4 /*
5 * urcu-bp.h
6 *
7 * Userspace RCU header, "bulletproof" version.
8 *
9 * Slower RCU read-side adapted for tracing library. Does not require thread
10 * registration nor unregistration. Also signal-safe.
11 *
12 * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
13 * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
14 *
15 * LGPL-compatible code should include this header with :
16 *
17 * #define _LGPL_SOURCE
18 * #include <urcu.h>
19 *
20 * This library is free software; you can redistribute it and/or
21 * modify it under the terms of the GNU Lesser General Public
22 * License as published by the Free Software Foundation; either
23 * version 2.1 of the License, or (at your option) any later version.
24 *
25 * This library is distributed in the hope that it will be useful,
26 * but WITHOUT ANY WARRANTY; without even the implied warranty of
27 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
28 * Lesser General Public License for more details.
29 *
30 * You should have received a copy of the GNU Lesser General Public
31 * License along with this library; if not, write to the Free Software
32 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
33 *
34 * IBM's contributions to this file may be relicensed under LGPLv2 or later.
35 */
36
37 #include <stdlib.h>
38 #include <pthread.h>
39
40 /*
41 * See urcu-pointer.h and urcu-pointer-static.h for pointer publication headers.
42 */
43 #include <urcu-pointer.h>
44
45 #ifdef __cplusplus
46 extern "C" {
47 #endif
48
49 /*
50 * Important !
51 *
52 * Each thread containing read-side critical sections must be registered
53 * with rcu_register_thread() before calling rcu_read_lock().
54 * rcu_unregister_thread() should be called before the thread exits.
55 */
56
57 #ifdef _LGPL_SOURCE
58
59 #include <urcu-bp-static.h>
60
61 /*
62 * Mappings for static use of the userspace RCU library.
63 * Should only be used in LGPL-compatible code.
64 */
65
66 /*
67 * rcu_read_lock()
68 * rcu_read_unlock()
69 *
70 * Mark the beginning and end of a read-side critical section.
71 */
72 #define rcu_read_lock() _rcu_read_lock()
73 #define rcu_read_unlock() _rcu_read_unlock()
74
75 #else /* !_LGPL_SOURCE */
76
77 /*
78 * library wrappers to be used by non-LGPL compatible source code.
79 * See LGPL-only urcu-pointer-static.h for documentation.
80 */
81
82 extern void rcu_read_lock(void);
83 extern void rcu_read_unlock(void);
84
85 #endif /* !_LGPL_SOURCE */
86
87 extern void synchronize_rcu(void);
88
89 /*
90 * rcu_bp_before_fork, rcu_bp_after_fork_parent and rcu_bp_after_fork_child
91 * should be called around fork() system calls when the child process is not
92 * expected to immediately perform an exec(). For pthread users, see
93 * pthread_atfork(3).
94 */
95 extern void rcu_bp_before_fork(void);
96 extern void rcu_bp_after_fork_parent(void);
97 extern void rcu_bp_after_fork_child(void);
98
99 /*
100 * In the bulletproof version, the following functions are no-ops.
101 */
102 static inline void rcu_register_thread(void)
103 {
104 }
105
106 static inline void rcu_unregister_thread(void)
107 {
108 }
109
110 static inline void rcu_init(void)
111 {
112 }
113
114 #ifdef __cplusplus
115 }
116 #endif
117
118 #endif /* _URCU_BP_H */
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