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- // <semaphore> -*- C++ -*-
- // Copyright (C) 2020-2022 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
- #pragma GCC system_header
- #if __cplusplus > 201703L
- #include <bits/semaphore_base.h>
- #if __cpp_lib_atomic_wait || _GLIBCXX_HAVE_POSIX_SEMAPHORE
- namespace std _GLIBCXX_VISIBILITY(default)
- {
- _GLIBCXX_BEGIN_NAMESPACE_VERSION
- #define __cpp_lib_semaphore 201907L
- template<ptrdiff_t __least_max_value = __semaphore_impl::_S_max>
- class counting_semaphore
- {
- static_assert(__least_max_value >= 0);
- static_assert(__least_max_value <= __semaphore_impl::_S_max);
- __semaphore_impl _M_sem;
- public:
- explicit counting_semaphore(ptrdiff_t __desired) noexcept
- : _M_sem(__desired)
- { }
- ~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(noexcept(_M_sem._M_release(1)))
- { _M_sem._M_release(__update); }
- 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); }
- };
- using binary_semaphore = std::counting_semaphore<1>;
- _GLIBCXX_END_NAMESPACE_VERSION
- } // namespace
- #endif // cpp_lib_atomic_wait || _GLIBCXX_HAVE_POSIX_SEMAPHORE
- #endif // C++20
- #endif // _GLIBCXX_SEMAPHORE
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