FM / bits

/usr/include/c++/11/bits

Name	Size	Mode	Actions
algorithmfwd.h	24547	0644	edit dl rm
align.h	3711	0644	edit dl rm
allocated_ptr.h	3329	0644	edit dl rm
allocator.h	9737	0644	edit dl rm
alloc_traits.h	27632	0644	edit dl rm
atomic_base.h	57414	0644	edit dl rm
atomic_futex.h	12394	0644	edit dl rm
atomic_lockfree_defines.h	2353	0644	edit dl rm
atomic_timed_wait.h	13530	0644	edit dl rm
atomic_wait.h	12557	0644	edit dl rm
basic_ios.h	16080	0644	edit dl rm
basic_ios.tcc	6083	0644	edit dl rm
basic_string.h	251944	0644	edit dl rm
basic_string.tcc	54189	0644	edit dl rm
boost_concept_check.h	27182	0644	edit dl rm
c++0x_warning.h	1474	0644	edit dl rm
charconv.h	3435	0644	edit dl rm
char_traits.h	29350	0644	edit dl rm
codecvt.h	25500	0644	edit dl rm
concept_check.h	3423	0644	edit dl rm
cpp_type_traits.h	14003	0644	edit dl rm
cxxabi_forced.h	1811	0644	edit dl rm
cxxabi_init_exception.h	2220	0644	edit dl rm
deque.tcc	42361	0644	edit dl rm
enable_special_members.h	12452	0644	edit dl rm
erase_if.h	2066	0644	edit dl rm
exception.h	2504	0644	edit dl rm
exception_defines.h	1645	0644	edit dl rm
exception_ptr.h	7640	0644	edit dl rm
forward_list.h	50387	0644	edit dl rm
forward_list.tcc	14035	0644	edit dl rm
fstream.tcc	33672	0644	edit dl rm
fs_dir.h	16409	0644	edit dl rm
fs_fwd.h	10771	0644	edit dl rm
fs_ops.h	10739	0644	edit dl rm
fs_path.h	39745	0644	edit dl rm
functexcept.h	3509	0644	edit dl rm
functional_hash.h	8591	0644	edit dl rm
gslice.h	5519	0644	edit dl rm
gslice_array.h	7892	0644	edit dl rm
hashtable.h	84951	0644	edit dl rm
hashtable_policy.h	62156	0644	edit dl rm
hash_bytes.h	2146	0644	edit dl rm
indirect_array.h	7902	0644	edit dl rm
invoke.h	6059	0644	edit dl rm
ios_base.h	31934	0644	edit dl rm
istream.tcc	31595	0644	edit dl rm
iterator_concepts.h	33335	0644	edit dl rm
list.tcc	17201	0644	edit dl rm
localefwd.h	5943	0644	edit dl rm
locale_classes.h	25044	0644	edit dl rm
locale_classes.tcc	8375	0644	edit dl rm
locale_conv.h	18822	0644	edit dl rm
locale_facets.h	93655	0644	edit dl rm
locale_facets.tcc	40463	0644	edit dl rm
locale_facets_nonio.h	69704	0644	edit dl rm
locale_facets_nonio.tcc	47533	0644	edit dl rm
mask_array.h	7716	0644	edit dl rm
max_size_type.h	22715	0644	edit dl rm
memoryfwd.h	2504	0644	edit dl rm
move.h	6798	0644	edit dl rm
nested_exception.h	4887	0644	edit dl rm
node_handle.h	10920	0644	edit dl rm
ostream.tcc	12315	0644	edit dl rm
ostream_insert.h	4038	0644	edit dl rm
parse_numbers.h	7980	0644	edit dl rm
postypes.h	8465	0644	edit dl rm
predefined_ops.h	10177	0644	edit dl rm
ptr_traits.h	6708	0644	edit dl rm
quoted_string.h	5053	0644	edit dl rm
random.h	178359	0644	edit dl rm
random.tcc	105688	0644	edit dl rm
ranges_algo.h	116831	0644	edit dl rm
ranges_algobase.h	18871	0644	edit dl rm
ranges_base.h	24392	0644	edit dl rm
ranges_cmp.h	6017	0644	edit dl rm
ranges_uninitialized.h	18130	0644	edit dl rm
ranges_util.h	20591	0644	edit dl rm
range_access.h	10707	0644	edit dl rm
refwrap.h	13208	0644	edit dl rm
regex.h	103969	0644	edit dl rm
regex.tcc	16492	0644	edit dl rm
regex_automaton.h	10788	0644	edit dl rm
regex_automaton.tcc	7722	0644	edit dl rm
regex_compiler.h	16219	0644	edit dl rm
regex_compiler.tcc	19158	0644	edit dl rm
regex_constants.h	15549	0644	edit dl rm
regex_error.h	5015	0644	edit dl rm
regex_executor.h	8852	0644	edit dl rm
regex_executor.tcc	18837	0644	edit dl rm
regex_scanner.h	7047	0644	edit dl rm
regex_scanner.tcc	15249	0644	edit dl rm
semaphore_base.h	7936	0644	edit dl rm
shared_ptr.h	30981	0644	edit dl rm
shared_ptr_atomic.h	9874	0644	edit dl rm
shared_ptr_base.h	54907	0644	edit dl rm
slice_array.h	9619	0644	edit dl rm
specfun.h	47240	0644	edit dl rm
sstream.tcc	10148	0644	edit dl rm
std_abs.h	3384	0644	edit dl rm
std_function.h	22863	0644	edit dl rm
std_mutex.h	6443	0644	edit dl rm
std_thread.h	8589	0644	edit dl rm
stl_algo.h	214703	0644	edit dl rm
stl_algobase.h	76254	0644	edit dl rm
stl_bvector.h	35574	0644	edit dl rm
stl_construct.h	8800	0644	edit dl rm
stl_deque.h	76970	0644	edit dl rm
stl_function.h	43897	0644	edit dl rm
stl_heap.h	20756	0644	edit dl rm
stl_iterator.h	78851	0644	edit dl rm
stl_iterator_base_funcs.h	8178	0644	edit dl rm
stl_iterator_base_types.h	9662	0644	edit dl rm
stl_list.h	69779	0644	edit dl rm
stl_map.h	54693	0644	edit dl rm
stl_multimap.h	43534	0644	edit dl rm
stl_multiset.h	37675	0644	edit dl rm
stl_numeric.h	14601	0644	edit dl rm
stl_pair.h	20135	0644	edit dl rm
stl_queue.h	25036	0644	edit dl rm
stl_raw_storage_iter.h	3830	0644	edit dl rm
stl_relops.h	4594	0644	edit dl rm
stl_set.h	37939	0644	edit dl rm
stl_stack.h	12684	0644	edit dl rm
stl_tempbuf.h	8655	0644	edit dl rm
stl_tree.h	73922	0644	edit dl rm
stl_uninitialized.h	34013	0644	edit dl rm
stl_vector.h	65919	0644	edit dl rm
streambuf.tcc	4929	0644	edit dl rm
streambuf_iterator.h	15532	0644	edit dl rm
stream_iterator.h	7697	0644	edit dl rm
stringfwd.h	2690	0644	edit dl rm
string_view.tcc	7167	0644	edit dl rm
this_thread_sleep.h	3307	0644	edit dl rm
uniform_int_dist.h	13052	0644	edit dl rm
unique_lock.h	6143	0644	edit dl rm
unique_ptr.h	32537	0644	edit dl rm
unordered_map.h	76669	0644	edit dl rm
unordered_set.h	62934	0644	edit dl rm
uses_allocator.h	6906	0644	edit dl rm
uses_allocator_args.h	7562	0644	edit dl rm
valarray_after.h	23283	0644	edit dl rm
valarray_array.h	21295	0644	edit dl rm
valarray_array.tcc	7254	0644	edit dl rm
valarray_before.h	19142	0644	edit dl rm
vector.tcc	30985	0644	edit dl rm

Edit: /usr/include/c++/11/bits/semaphore_base.h (7936B)

// -*- C++ -*- header.

// Copyright (C) 2020-2021 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 bits/semaphore_base.h
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{semaphore}
 */

#ifndef _GLIBCXX_SEMAPHORE_BASE_H
#define _GLIBCXX_SEMAPHORE_BASE_H 1

#pragma GCC system_header

#include <bits/atomic_base.h>
#if __cpp_lib_atomic_wait
#include <bits/atomic_timed_wait.h>
#include <ext/numeric_traits.h>
#endif // __cpp_lib_atomic_wait

#ifdef _GLIBCXX_HAVE_POSIX_SEMAPHORE
# include <exception>	// std::terminate
# include <cerrno>	// errno, EINTR, EAGAIN etc.
# include <limits.h>	// SEM_VALUE_MAX
# include <semaphore.h>	// sem_t, sem_init, sem_wait, sem_post etc.
#endif

#include <chrono>
#include <type_traits>

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

#ifdef _GLIBCXX_HAVE_POSIX_SEMAPHORE
  struct __platform_semaphore
  {
    using __clock_t = chrono::system_clock;
#ifdef SEM_VALUE_MAX
    static constexpr ptrdiff_t _S_max = SEM_VALUE_MAX;
#else
    static constexpr ptrdiff_t _S_max = _POSIX_SEM_VALUE_MAX;
#endif

explicit __platform_semaphore(ptrdiff_t __count) noexcept
    {
      sem_init(&_M_semaphore, 0, __count);
    }

__platform_semaphore(const __platform_semaphore&) = delete;
    __platform_semaphore& operator=(const __platform_semaphore&) = delete;

~__platform_semaphore()
    { sem_destroy(&_M_semaphore); }

_GLIBCXX_ALWAYS_INLINE void
    _M_acquire() noexcept
    {
      for (;;)
	{
	  auto __err = sem_wait(&_M_semaphore);
	  if (__err && (errno == EINTR))
	    continue;
	  else if (__err)
	    std::terminate();
	  else
	    break;
	}
    }

_GLIBCXX_ALWAYS_INLINE bool
    _M_try_acquire() noexcept
    {
      for (;;)
	{
	  auto __err = sem_trywait(&_M_semaphore);
	  if (__err && (errno == EINTR))
	    continue;
	  else if (__err && (errno == EAGAIN))
	    return false;
	  else if (__err)
	    std::terminate();
	  else
	    break;
	}
      return true;
    }

_GLIBCXX_ALWAYS_INLINE void
    _M_release(std::ptrdiff_t __update) noexcept
    {
      for(; __update != 0; --__update)
	{
	   auto __err = sem_post(&_M_semaphore);
	   if (__err)
	     std::terminate();
	}
    }

bool
    _M_try_acquire_until_impl(const chrono::time_point<__clock_t>& __atime)
      noexcept
    {

auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
      auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);

struct timespec __ts =
      {
	static_cast<std::time_t>(__s.time_since_epoch().count()),
	static_cast<long>(__ns.count())
      };

for (;;)
	{
	  if (auto __err = sem_timedwait(&_M_semaphore, &__ts))
	    {
	      if (errno == EINTR)
		continue;
	      else if (errno == ETIMEDOUT || errno == EINVAL)
		return false;
	      else
		std::terminate();
	    }
	  else
	    break;
	}
      return true;
    }

template<typename _Clock, typename _Duration>
      bool
      _M_try_acquire_until(const chrono::time_point<_Clock,
			   _Duration>& __atime) noexcept
      {
	if constexpr (std::is_same_v<__clock_t, _Clock>)
	  {
	    return _M_try_acquire_until_impl(__atime);
	  }
	else
	  {
	    const typename _Clock::time_point __c_entry = _Clock::now();
	    const auto __s_entry = __clock_t::now();
	    const auto __delta = __atime - __c_entry;
	    const auto __s_atime = __s_entry + __delta;
	    if (_M_try_acquire_until_impl(__s_atime))
	      return true;

// We got a timeout when measured against __clock_t but
	    // we need to check against the caller-supplied clock
	    // to tell whether we should return a timeout.
	    return (_Clock::now() < __atime);
	  }
      }

template<typename _Rep, typename _Period>
      _GLIBCXX_ALWAYS_INLINE bool
      _M_try_acquire_for(const chrono::duration<_Rep, _Period>& __rtime)
	noexcept
      { return _M_try_acquire_until(__clock_t::now() + __rtime); }

private:
    sem_t _M_semaphore;
  };
#endif // _GLIBCXX_HAVE_POSIX_SEMAPHORE

#if __cpp_lib_atomic_wait
  struct __atomic_semaphore
  {
    static constexpr ptrdiff_t _S_max = __gnu_cxx::__int_traits<int>::__max;
    explicit __atomic_semaphore(__detail::__platform_wait_t __count) noexcept
      : _M_counter(__count)
    {
      __glibcxx_assert(__count >= 0 && __count <= _S_max);
    }

__atomic_semaphore(const __atomic_semaphore&) = delete;
    __atomic_semaphore& operator=(const __atomic_semaphore&) = delete;

static _GLIBCXX_ALWAYS_INLINE bool
    _S_do_try_acquire(__detail::__platform_wait_t* __counter) noexcept
    {
      auto __old = __atomic_impl::load(__counter, memory_order::acquire);
      if (__old == 0)
	return false;

return __atomic_impl::compare_exchange_strong(__counter,
						    __old, __old - 1,
						    memory_order::acquire,
						    memory_order::relaxed);
    }

_GLIBCXX_ALWAYS_INLINE void
    _M_acquire() noexcept
    {
      auto const __pred =
	[this] { return _S_do_try_acquire(&this->_M_counter); };
      std::__atomic_wait_address_bare(&_M_counter, __pred);
    }

bool
    _M_try_acquire() noexcept
    {
      auto const __pred =
	[this] { return _S_do_try_acquire(&this->_M_counter); };
      return std::__detail::__atomic_spin(__pred);
    }

template<typename _Clock, typename _Duration>
      _GLIBCXX_ALWAYS_INLINE bool
      _M_try_acquire_until(const chrono::time_point<_Clock,
			   _Duration>& __atime) noexcept
      {
	auto const __pred =
	  [this] { return _S_do_try_acquire(&this->_M_counter); };

return __atomic_wait_address_until_bare(&_M_counter, __pred, __atime);
      }

template<typename _Rep, typename _Period>
      _GLIBCXX_ALWAYS_INLINE bool
      _M_try_acquire_for(const chrono::duration<_Rep, _Period>& __rtime)
	noexcept
      {
	auto const __pred =
	  [this] { return _S_do_try_acquire(&this->_M_counter); };

return __atomic_wait_address_for_bare(&_M_counter, __pred, __rtime);
      }

_GLIBCXX_ALWAYS_INLINE void
    _M_release(ptrdiff_t __update) noexcept
    {
      if (0 < __atomic_impl::fetch_add(&_M_counter, __update, memory_order_release))
	return;
      if (__update > 1)
	__atomic_notify_address_bare(&_M_counter, true);
      else
	__atomic_notify_address_bare(&_M_counter, true);
// FIXME - Figure out why this does not wake a waiting thread
//	__atomic_notify_address_bare(&_M_counter, false);
    }

private:
    alignas(__detail::__platform_wait_alignment)
    __detail::__platform_wait_t _M_counter;
  };
#endif // __cpp_lib_atomic_wait

// Note: the _GLIBCXX_USE_POSIX_SEMAPHORE macro can be used to force the
// use of Posix semaphores (sem_t). Doing so however, alters the ABI.
#if defined __cpp_lib_atomic_wait && !_GLIBCXX_USE_POSIX_SEMAPHORE
  using __semaphore_impl = __atomic_semaphore;
#elif _GLIBCXX_HAVE_POSIX_SEMAPHORE
  using __semaphore_impl = __platform_semaphore;
#endif

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // _GLIBCXX_SEMAPHORE_BASE_H

cmd: