1// condition_variable -*- C++ -*-
2
3// Copyright (C) 2008-2017 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25#include <condition_variable>
26#include <cstdlib>
27
28#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
29
30namespace std _GLIBCXX_VISIBILITY(default)
31{
32_GLIBCXX_BEGIN_NAMESPACE_VERSION
33
34#ifdef __GTHREAD_COND_INIT
35 condition_variable::condition_variable() noexcept = default;
36#else
37 condition_variable::condition_variable() noexcept
38 {
39 __GTHREAD_COND_INIT_FUNCTION(&_M_cond);
40 }
41#endif
42
43 condition_variable::~condition_variable() noexcept
44 {
45 // XXX no thread blocked
46 /* int __e = */ __gthread_cond_destroy(&_M_cond);
47 // if __e == EBUSY then blocked
48 }
49
50 void
51 condition_variable::wait(unique_lock<mutex>& __lock) noexcept
52 {
53 int __e = __gthread_cond_wait(&_M_cond, __lock.mutex()->native_handle());
54
55 if (__e)
56 std::terminate();
57 }
58
59 void
60 condition_variable::notify_one() noexcept
61 {
62 int __e = __gthread_cond_signal(&_M_cond);
63
64 // XXX not in spec
65 // EINVAL
66 if (__e)
67 __throw_system_error(__e);
68 }
69
70 void
71 condition_variable::notify_all() noexcept
72 {
73 int __e = __gthread_cond_broadcast(&_M_cond);
74
75 // XXX not in spec
76 // EINVAL
77 if (__e)
78 __throw_system_error(__e);
79 }
80
81 extern void
82 __at_thread_exit(__at_thread_exit_elt*);
83
84 namespace
85 {
86 __gthread_key_t key;
87
88 void run(void* p)
89 {
90 auto elt = (__at_thread_exit_elt*)p;
91 while (elt)
92 {
93 auto next = elt->_M_next;
94 elt->_M_cb(elt);
95 elt = next;
96 }
97 }
98
99 void run()
100 {
101 auto elt = (__at_thread_exit_elt*)__gthread_getspecific(key);
102 __gthread_setspecific(key, nullptr);
103 run(elt);
104 }
105
106 struct notifier final : __at_thread_exit_elt
107 {
108 notifier(condition_variable& cv, unique_lock<mutex>& l)
109 : cv(&cv), mx(l.release())
110 {
111 _M_cb = &notifier::run;
112 __at_thread_exit(this);
113 }
114
115 ~notifier()
116 {
117 mx->unlock();
118 cv->notify_all();
119 }
120
121 condition_variable* cv;
122 mutex* mx;
123
124 static void run(void* p) { delete static_cast<notifier*>(p); }
125 };
126
127
128 void key_init() {
129 struct key_s {
130 key_s() { __gthread_key_create (&key, run); }
131 ~key_s() { __gthread_key_delete (key); }
132 };
133 static key_s ks;
134 // Also make sure the callbacks are run by std::exit.
135 std::atexit (run);
136 }
137 }
138
139 void
140 __at_thread_exit(__at_thread_exit_elt* elt)
141 {
142 static __gthread_once_t once = __GTHREAD_ONCE_INIT;
143 __gthread_once (&once, key_init);
144
145 elt->_M_next = (__at_thread_exit_elt*)__gthread_getspecific(key);
146 __gthread_setspecific(key, elt);
147 }
148
149 void
150 notify_all_at_thread_exit(condition_variable& cv, unique_lock<mutex> l)
151 {
152 (void) new notifier{cv, l};
153 }
154
155_GLIBCXX_END_NAMESPACE_VERSION
156} // namespace
157
158#endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
159