blob: ca1bffe371a0b265c33b5e762fb0e5b74f9390bd (
plain)
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
|
// <semaphore> -*- C++ -*-
// Copyright (C) 2020-2025 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file include/semaphore
* This is a Standard C++ Library header.
*/
#ifndef _GLIBCXX_SEMAPHORE
#define _GLIBCXX_SEMAPHORE 1
#ifdef _GLIBCXX_SYSHDR
#pragma GCC system_header
#endif
#include <bits/requires_hosted.h> // concurrency
#define __glibcxx_want_semaphore
#include <bits/version.h>
#ifdef __cpp_lib_semaphore // C++ >= 20 && hosted && atomic_wait
#include <bits/semaphore_base.h>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
template<ptrdiff_t __least_max_value = __semaphore_base<true>::_S_max>
class counting_semaphore
{
static_assert(__least_max_value >= 0);
using _Impl = __semaphore_impl<__least_max_value>;
_Impl _M_sem;
public:
constexpr explicit
counting_semaphore(ptrdiff_t __desired) noexcept
: _M_sem(__desired)
{ __glibcxx_assert(__desired >= 0 && __desired <= max()); }
~counting_semaphore() = default;
counting_semaphore(const counting_semaphore&) = delete;
counting_semaphore& operator=(const counting_semaphore&) = delete;
static constexpr ptrdiff_t
max() noexcept
{ return __least_max_value; }
void
release(ptrdiff_t __update = 1) noexcept
{
[[maybe_unused]] ptrdiff_t __old = _M_sem._M_release(__update);
__glibcxx_assert(__update >= 0 && __update <= max() - __old);
}
void
acquire() noexcept(noexcept(_M_sem._M_acquire()))
{ _M_sem._M_acquire(); }
bool
try_acquire() noexcept(noexcept(_M_sem._M_try_acquire()))
{ return _M_sem._M_try_acquire(); }
template<typename _Rep, typename _Period>
bool
try_acquire_for(const std::chrono::duration<_Rep, _Period>& __rtime)
{ return _M_sem._M_try_acquire_for(__rtime); }
template<typename _Clock, typename _Dur>
bool
try_acquire_until(const std::chrono::time_point<_Clock, _Dur>& __atime)
{ return _M_sem._M_try_acquire_until(__atime); }
};
/** @brief A binary semaphore
*
* @since C++20
*/
using binary_semaphore = std::counting_semaphore<1>;
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
#endif // __cpp_lib_semaphore
#endif // _GLIBCXX_SEMAPHORE
|
