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The C and C++ Include Header Files

/usr/include/c++/13/semaphore

$ cat -n /usr/include/c++/13/semaphore

     1	// <semaphore> -*- C++ -*-
     2	
     3	// Copyright (C) 2020-2023 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	/** @file include/semaphore
    26	 *  This is a Standard C++ Library header.
    27	 */
    28	
    29	#ifndef _GLIBCXX_SEMAPHORE
    30	#define _GLIBCXX_SEMAPHORE 1
    31	
    32	#pragma GCC system_header
    33	
    34	#include <bits/requires_hosted.h> // concurrency
    35	
    36	#if __cplusplus > 201703L
    37	#include <bits/semaphore_base.h>
    38	
    39	#if __cpp_lib_atomic_wait || _GLIBCXX_HAVE_POSIX_SEMAPHORE
    40	namespace std _GLIBCXX_VISIBILITY(default)
    41	{
    42	_GLIBCXX_BEGIN_NAMESPACE_VERSION
    43	
    44	#define __cpp_lib_semaphore 201907L
    45	
    46	  template<ptrdiff_t __least_max_value = __semaphore_impl::_S_max>
    47	    class counting_semaphore
    48	    {
    49	      static_assert(__least_max_value >= 0);
    50	      static_assert(__least_max_value <= __semaphore_impl::_S_max);
    51	
    52	      __semaphore_impl _M_sem;
    53	
    54	    public:
    55	      explicit counting_semaphore(ptrdiff_t __desired) noexcept
    56		: _M_sem(__desired)
    57	      { }
    58	
    59	      ~counting_semaphore() = default;
    60	
    61	      counting_semaphore(const counting_semaphore&) = delete;
    62	      counting_semaphore& operator=(const counting_semaphore&) = delete;
    63	
    64	      static constexpr ptrdiff_t
    65	      max() noexcept
    66	      { return __least_max_value; }
    67	
    68	      void
    69	      release(ptrdiff_t __update = 1) noexcept(noexcept(_M_sem._M_release(1)))
    70	      { _M_sem._M_release(__update); }
    71	
    72	      void
    73	      acquire() noexcept(noexcept(_M_sem._M_acquire()))
    74	      { _M_sem._M_acquire(); }
    75	
    76	      bool
    77	      try_acquire() noexcept(noexcept(_M_sem._M_try_acquire()))
    78	      { return _M_sem._M_try_acquire(); }
    79	
    80	      template<typename _Rep, typename _Period>
    81		bool
    82		try_acquire_for(const std::chrono::duration<_Rep, _Period>& __rtime)
    83		{ return _M_sem._M_try_acquire_for(__rtime); }
    84	
    85	      template<typename _Clock, typename _Dur>
    86		bool
    87		try_acquire_until(const std::chrono::time_point<_Clock, _Dur>& __atime)
    88		{ return _M_sem._M_try_acquire_until(__atime); }
    89	    };
    90	
    91	  using binary_semaphore = std::counting_semaphore<1>;
    92	
    93	_GLIBCXX_END_NAMESPACE_VERSION
    94	} // namespace
    95	#endif // cpp_lib_atomic_wait || _GLIBCXX_HAVE_POSIX_SEMAPHORE
    96	#endif // C++20
    97	#endif // _GLIBCXX_SEMAPHORE
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