Edit: /usr/include/c++/11/condition_variable (12780B)
//
-*- C++ -*-
// Copyright (C) 2008-2021 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
// .
/** @file include/condition_variable
* This is a Standard C++ Library header.
*/
#ifndef _GLIBCXX_CONDITION_VARIABLE
#define _GLIBCXX_CONDITION_VARIABLE 1
#pragma GCC system_header
#if __cplusplus < 201103L
# include
#else
#include
#include
#include
#include
#include
#include
#if __cplusplus > 201703L
# include
#endif
#if defined(_GLIBCXX_HAS_GTHREADS)
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/**
* @defgroup condition_variables Condition Variables
* @ingroup concurrency
*
* Classes for condition_variable support.
* @{
*/
/// cv_status
enum class cv_status { no_timeout, timeout };
/// condition_variable
class condition_variable
{
using steady_clock = chrono::steady_clock;
using system_clock = chrono::system_clock;
#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
using __clock_t = steady_clock;
#else
using __clock_t = system_clock;
#endif
__condvar _M_cond;
public:
typedef __gthread_cond_t* native_handle_type;
condition_variable() noexcept;
~condition_variable() noexcept;
condition_variable(const condition_variable&) = delete;
condition_variable& operator=(const condition_variable&) = delete;
void
notify_one() noexcept;
void
notify_all() noexcept;
void
wait(unique_lock& __lock) noexcept;
template
void
wait(unique_lock& __lock, _Predicate __p)
{
while (!__p())
wait(__lock);
}
#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
template
cv_status
wait_until(unique_lock& __lock,
const chrono::time_point& __atime)
{ return __wait_until_impl(__lock, __atime); }
#endif
template
cv_status
wait_until(unique_lock& __lock,
const chrono::time_point& __atime)
{ return __wait_until_impl(__lock, __atime); }
template
cv_status
wait_until(unique_lock& __lock,
const chrono::time_point<_Clock, _Duration>& __atime)
{
#if __cplusplus > 201703L
static_assert(chrono::is_clock_v<_Clock>);
#endif
using __s_dur = typename __clock_t::duration;
const typename _Clock::time_point __c_entry = _Clock::now();
const __clock_t::time_point __s_entry = __clock_t::now();
const auto __delta = __atime - __c_entry;
const auto __s_atime = __s_entry +
chrono::__detail::ceil<__s_dur>(__delta);
if (__wait_until_impl(__lock, __s_atime) == cv_status::no_timeout)
return cv_status::no_timeout;
// 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.
if (_Clock::now() < __atime)
return cv_status::no_timeout;
return cv_status::timeout;
}
template
bool
wait_until(unique_lock& __lock,
const chrono::time_point<_Clock, _Duration>& __atime,
_Predicate __p)
{
while (!__p())
if (wait_until(__lock, __atime) == cv_status::timeout)
return __p();
return true;
}
template
cv_status
wait_for(unique_lock& __lock,
const chrono::duration<_Rep, _Period>& __rtime)
{
using __dur = typename steady_clock::duration;
return wait_until(__lock,
steady_clock::now() +
chrono::__detail::ceil<__dur>(__rtime));
}
template
bool
wait_for(unique_lock& __lock,
const chrono::duration<_Rep, _Period>& __rtime,
_Predicate __p)
{
using __dur = typename steady_clock::duration;
return wait_until(__lock,
steady_clock::now() +
chrono::__detail::ceil<__dur>(__rtime),
std::move(__p));
}
native_handle_type
native_handle()
{ return _M_cond.native_handle(); }
private:
#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
template
cv_status
__wait_until_impl(unique_lock& __lock,
const chrono::time_point& __atime)
{
auto __s = chrono::time_point_cast(__atime);
auto __ns = chrono::duration_cast(__atime - __s);
__gthread_time_t __ts =
{
static_cast(__s.time_since_epoch().count()),
static_cast(__ns.count())
};
_M_cond.wait_until(*__lock.mutex(), CLOCK_MONOTONIC, __ts);
return (steady_clock::now() < __atime
? cv_status::no_timeout : cv_status::timeout);
}
#endif
template
cv_status
__wait_until_impl(unique_lock& __lock,
const chrono::time_point& __atime)
{
auto __s = chrono::time_point_cast(__atime);
auto __ns = chrono::duration_cast(__atime - __s);
__gthread_time_t __ts =
{
static_cast(__s.time_since_epoch().count()),
static_cast(__ns.count())
};
_M_cond.wait_until(*__lock.mutex(), __ts);
return (system_clock::now() < __atime
? cv_status::no_timeout : cv_status::timeout);
}
};
void
notify_all_at_thread_exit(condition_variable&, unique_lock);
struct __at_thread_exit_elt
{
__at_thread_exit_elt* _M_next;
void (*_M_cb)(void*);
};
inline namespace _V2 {
/// condition_variable_any
// Like above, but mutex is not required to have try_lock.
class condition_variable_any
{
#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
using __clock_t = chrono::steady_clock;
#else
using __clock_t = chrono::system_clock;
#endif
condition_variable _M_cond;
shared_ptr _M_mutex;
// scoped unlock - unlocks in ctor, re-locks in dtor
template
struct _Unlock
{
explicit _Unlock(_Lock& __lk) : _M_lock(__lk) { __lk.unlock(); }
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
~_Unlock() noexcept(false)
{
if (uncaught_exception())
{
__try
{ _M_lock.lock(); }
__catch(const __cxxabiv1::__forced_unwind&)
{ __throw_exception_again; }
__catch(...)
{ }
}
else
_M_lock.lock();
}
#pragma GCC diagnostic pop
_Unlock(const _Unlock&) = delete;
_Unlock& operator=(const _Unlock&) = delete;
_Lock& _M_lock;
};
public:
condition_variable_any() : _M_mutex(std::make_shared()) { }
~condition_variable_any() = default;
condition_variable_any(const condition_variable_any&) = delete;
condition_variable_any& operator=(const condition_variable_any&) = delete;
void
notify_one() noexcept
{
lock_guard __lock(*_M_mutex);
_M_cond.notify_one();
}
void
notify_all() noexcept
{
lock_guard __lock(*_M_mutex);
_M_cond.notify_all();
}
template
void
wait(_Lock& __lock)
{
shared_ptr __mutex = _M_mutex;
unique_lock __my_lock(*__mutex);
_Unlock<_Lock> __unlock(__lock);
// *__mutex must be unlocked before re-locking __lock so move
// ownership of *__mutex lock to an object with shorter lifetime.
unique_lock __my_lock2(std::move(__my_lock));
_M_cond.wait(__my_lock2);
}
template
void
wait(_Lock& __lock, _Predicate __p)
{
while (!__p())
wait(__lock);
}
template
cv_status
wait_until(_Lock& __lock,
const chrono::time_point<_Clock, _Duration>& __atime)
{
shared_ptr __mutex = _M_mutex;
unique_lock __my_lock(*__mutex);
_Unlock<_Lock> __unlock(__lock);
// *__mutex must be unlocked before re-locking __lock so move
// ownership of *__mutex lock to an object with shorter lifetime.
unique_lock __my_lock2(std::move(__my_lock));
return _M_cond.wait_until(__my_lock2, __atime);
}
template
bool
wait_until(_Lock& __lock,
const chrono::time_point<_Clock, _Duration>& __atime,
_Predicate __p)
{
while (!__p())
if (wait_until(__lock, __atime) == cv_status::timeout)
return __p();
return true;
}
template
cv_status
wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime)
{ return wait_until(__lock, __clock_t::now() + __rtime); }
template
bool
wait_for(_Lock& __lock,
const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p)
{ return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }
#ifdef __cpp_lib_jthread
template
bool wait(_Lock& __lock,
stop_token __stoken,
_Predicate __p)
{
if (__stoken.stop_requested())
{
return __p();
}
std::stop_callback __cb(__stoken, [this] { notify_all(); });
shared_ptr __mutex = _M_mutex;
while (!__p())
{
unique_lock __my_lock(*__mutex);
if (__stoken.stop_requested())
{
return false;
}
// *__mutex must be unlocked before re-locking __lock so move
// ownership of *__mutex lock to an object with shorter lifetime.
_Unlock<_Lock> __unlock(__lock);
unique_lock __my_lock2(std::move(__my_lock));
_M_cond.wait(__my_lock2);
}
return true;
}
template
bool wait_until(_Lock& __lock,
stop_token __stoken,
const chrono::time_point<_Clock, _Duration>& __abs_time,
_Predicate __p)
{
if (__stoken.stop_requested())
{
return __p();
}
std::stop_callback __cb(__stoken, [this] { notify_all(); });
shared_ptr __mutex = _M_mutex;
while (!__p())
{
bool __stop;
{
unique_lock __my_lock(*__mutex);
if (__stoken.stop_requested())
{
return false;
}
_Unlock<_Lock> __u(__lock);
unique_lock __my_lock2(std::move(__my_lock));
const auto __status = _M_cond.wait_until(__my_lock2, __abs_time);
__stop = (__status == std::cv_status::timeout) || __stoken.stop_requested();
}
if (__stop)
{
return __p();
}
}
return true;
}
template
bool wait_for(_Lock& __lock,
stop_token __stoken,
const chrono::duration<_Rep, _Period>& __rel_time,
_Predicate __p)
{
auto __abst = std::chrono::steady_clock::now() + __rel_time;
return wait_until(__lock,
std::move(__stoken),
__abst,
std::move(__p));
}
#endif
};
} // end inline namespace
/// @} group condition_variables
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
#endif // _GLIBCXX_HAS_GTHREADS
#endif // C++11
#endif // _GLIBCXX_CONDITION_VARIABLE