libstdc++-v3/include/std/thread - rust-lang/gcc - Git at Google

 // <thread> -*- C++ -*-

 // Copyright (C) 2008-2025 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/thread
  *  This is a Standard C++ Library header.
  */

 #ifndef _GLIBCXX_THREAD
 #define _GLIBCXX_THREAD 1

 #ifdef _GLIBCXX_SYSHDR
 #pragma GCC system_header
 #endif

 #include <bits/requires_hosted.h> // concurrency

 #if __cplusplus < 201103L
 # include <bits/c++0x_warning.h>
 #else

 #if __cplusplus > 201703L
 # include <compare>	// std::strong_ordering
 # include <stop_token>	// std::stop_source, std::stop_token, std::nostopstate
 #endif

 #include <bits/std_thread.h> // std::thread, get_id, yield
 #include <bits/this_thread_sleep.h> // std::this_thread::sleep_for, sleep_until

 #define __glibcxx_want_jthread
 #define __glibcxx_want_formatters
 #include <bits/version.h>

 #if __cpp_lib_formatters
 # include <format>
 #endif

 namespace std _GLIBCXX_VISIBILITY(default)
 {
 _GLIBCXX_BEGIN_NAMESPACE_VERSION

   /**
    * @defgroup threads Threads
    * @ingroup concurrency
    * @since C++11
    *
    * Classes for thread support.
    * @{
    */

   // std::thread is defined in <bits/std_thread.h>

   /// @relates std::thread::id @{

 #if __cpp_lib_three_way_comparison
   inline strong_ordering
   operator<=>(thread::id __x, thread::id __y) noexcept
   { return __x._M_thread <=> __y._M_thread; }
 #else
   inline bool
   operator!=(thread::id __x, thread::id __y) noexcept
   { return !(__x == __y); }

   inline bool
   operator<(thread::id __x, thread::id __y) noexcept
   {
     // Pthreads doesn't define any way to do this, so we just have to
     // assume native_handle_type is LessThanComparable.
     return __x._M_thread < __y._M_thread;
   }

   inline bool
   operator<=(thread::id __x, thread::id __y) noexcept
   { return !(__y < __x); }

   inline bool
   operator>(thread::id __x, thread::id __y) noexcept
   { return __y < __x; }

   inline bool
   operator>=(thread::id __x, thread::id __y) noexcept
   { return !(__x < __y); }
 #endif // __cpp_lib_three_way_comparison

   template<class _CharT, class _Traits>
     inline basic_ostream<_CharT, _Traits>&
     operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id)
     {
       // Convert non-void pointers to const void* for formatted output.
       using __output_type
 	= __conditional_t<is_pointer<thread::native_handle_type>::value,
 			  const void*,
 			  thread::native_handle_type>;

       if (__id == thread::id())
 	return __out << "thread::id of a non-executing thread";
       else
 	return __out << static_cast<__output_type>(__id._M_thread);
     }
   /// @}

 #ifdef __cpp_lib_jthread // C++ >= 20

   /// @cond undocumented
 #ifndef __STRICT_ANSI__
     // As an extension we support invoking a pointer-to-member-function that
     // expects a stop_token as the first argument. See PR libstdc++/100612.
     template<typename _Callable, typename... _Args>
       constexpr bool __pmf_expects_stop_token = false;

     template<typename _Callable, typename _Obj, typename... _Args>
       requires is_member_function_pointer_v<remove_reference_t<_Callable>>
       constexpr bool __pmf_expects_stop_token<_Callable, _Obj, _Args...>
 	= is_invocable_v<_Callable, _Obj, stop_token, _Args...>;
 #endif
     /// @endcond

   /** A thread with cancellation and automatic joining.
    *
    * Unlike `std::thread`, destroying a joinable `std::jthread` will not
    * terminate the process. Instead, it will try to request its thread to
    * stop, then will join it.
    *
    * A `std::jthread` has a `std::stop_source` member which will be passed
    * as the first argument to the callable that runs in the new thread
    * (as long as the callable will accept that argument). That can then
    * be used to send a stop request that the new thread can test for.
    *
    * @headerfile thread
    * @since C++20
    */
   class jthread
   {
   public:
     using id = thread::id;
     using native_handle_type = thread::native_handle_type;

     jthread() noexcept
     : _M_stop_source{nostopstate}
     { }

     template<typename _Callable, typename... _Args,
 	     typename = enable_if_t<!is_same_v<remove_cvref_t<_Callable>,
 					       jthread>>>
       explicit
       jthread(_Callable&& __f, _Args&&... __args)
       : _M_thread{_S_create(_M_stop_source, std::forward<_Callable>(__f),
 			    std::forward<_Args>(__args)...)}
       { }

     jthread(const jthread&) = delete;
     jthread(jthread&&) noexcept = default;

     ~jthread()
     {
       if (joinable())
         {
           request_stop();
           join();
         }
     }

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

     jthread&
     operator=(jthread&& __other) noexcept
     {
       std::jthread(std::move(__other)).swap(*this);
       return *this;
     }

     void
     swap(jthread& __other) noexcept
     {
       std::swap(_M_stop_source, __other._M_stop_source);
       std::swap(_M_thread, __other._M_thread);
     }

     [[nodiscard]] bool
     joinable() const noexcept
     {
       return _M_thread.joinable();
     }

     void
     join()
     {
       _M_thread.join();
     }

     void
     detach()
     {
       _M_thread.detach();
     }

     [[nodiscard]] id
     get_id() const noexcept
     {
       return _M_thread.get_id();
     }

     [[nodiscard]] native_handle_type
     native_handle()
     {
       return _M_thread.native_handle();
     }

     [[nodiscard]] static unsigned
     hardware_concurrency() noexcept
     {
       return thread::hardware_concurrency();
     }

     [[nodiscard]] stop_source
     get_stop_source() noexcept
     {
       return _M_stop_source;
     }

     [[nodiscard]] stop_token
     get_stop_token() const noexcept
     {
       return _M_stop_source.get_token();
     }

     bool request_stop() noexcept
     {
       return _M_stop_source.request_stop();
     }

     friend void swap(jthread& __lhs, jthread& __rhs) noexcept
     {
       __lhs.swap(__rhs);
     }

   private:
     template<typename _Callable, typename... _Args>
       static thread
       _S_create(stop_source& __ssrc, _Callable&& __f, _Args&&... __args)
       {
 #ifndef __STRICT_ANSI__
 	if constexpr (__pmf_expects_stop_token<_Callable, _Args...>)
 	  return _S_create_pmf(__ssrc, __f, std::forward<_Args>(__args)...);
 	else
 #endif
 	if constexpr(is_invocable_v<decay_t<_Callable>, stop_token,
 				    decay_t<_Args>...>)
 	  return thread{std::forward<_Callable>(__f), __ssrc.get_token(),
 			std::forward<_Args>(__args)...};
 	else
 	  {
 	    static_assert(is_invocable_v<decay_t<_Callable>,
 					 decay_t<_Args>...>,
 			  "std::jthread arguments must be invocable after"
 			  " conversion to rvalues");
 	    return thread{std::forward<_Callable>(__f),
 			  std::forward<_Args>(__args)...};
 	  }
       }

 #ifndef __STRICT_ANSI__
     template<typename _Callable, typename _Obj, typename... _Args>
       static thread
       _S_create_pmf(stop_source& __ssrc, _Callable __f, _Obj&& __obj,
 		    _Args&&... __args)
       {
 	return thread{__f, std::forward<_Obj>(__obj), __ssrc.get_token(),
 		      std::forward<_Args>(__args)...};
       }
 #endif

     stop_source _M_stop_source;
     thread _M_thread;
   };
 #endif // __cpp_lib_jthread

 #ifdef __cpp_lib_formatters // C++ >= 23
   template<typename _CharT>
     requires is_pointer_v<thread::native_handle_type>
       || is_integral_v<thread::native_handle_type>
     class formatter<thread::id, _CharT>
     {
     public:
       constexpr typename basic_format_parse_context<_CharT>::iterator
       parse(basic_format_parse_context<_CharT>& __pc)
       {
 	__format::_Spec<_CharT> __spec{};
 	const auto __last = __pc.end();
 	auto __first = __pc.begin();

 	auto __finalize = [this, &__spec] {
 	  _M_spec = __spec;
 	};

 	auto __finished = [&] {
 	  if (__first == __last || *__first == '}')
 	    {
 	      __finalize();
 	      return true;
 	    }
 	  return false;
 	};

 	if (__finished())
 	  return __first;

 	__first = __spec._M_parse_fill_and_align(__first, __last);
 	if (__finished())
 	  return __first;

 	__first = __spec._M_parse_width(__first, __last, __pc);
 	if (__finished())
 	  return __first;

 	__throw_format_error("format error: invalid format-spec for "
 			     "std::thread::id");
       }

       template<typename _Out>
 	typename basic_format_context<_Out, _CharT>::iterator
 	format(thread::id __id, basic_format_context<_Out, _CharT>& __fc) const
 	{
 	  basic_string_view<_CharT> __sv;
 	  if constexpr (is_same_v<_CharT, char>)
 	    __sv = "{}thread::id of a non-executing thread";
 	  else
 	    __sv = L"{}thread::id of a non-executing thread";
 	  basic_string<_CharT> __str;
 	  if (__id == thread::id())
 	    __sv.remove_prefix(2);
 	  else
 	    {
 	      using _FmtStr = __format::_Runtime_format_string<_CharT>;
 	      // Convert non-void pointers to const void* for formatted output.
 	      using __output_type
 		= __conditional_t<is_pointer_v<thread::native_handle_type>,
 				  const void*,
 				  thread::native_handle_type>;
 	      auto __o = static_cast<__output_type>(__id._M_thread);
 	      __sv = __str = std::format(_FmtStr(__sv.substr(0, 2)), __o);
 	    }
 	  return __format::__write_padded_as_spec(__sv, __sv.size(),
 						  __fc, _M_spec,
 						  __format::_Align_right);
 	}

     private:
       __format::_Spec<_CharT> _M_spec;
     };
 #endif // __cpp_lib_formatters

   /// @} group threads

 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace
 #endif // C++11
 #endif // _GLIBCXX_THREAD
	// <thread> -- C++ --

	// Copyright (C) 2008-2025 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/thread
	* This is a Standard C++ Library header.
	*/

	#ifndef _GLIBCXX_THREAD
	#define _GLIBCXX_THREAD 1

	#ifdef _GLIBCXX_SYSHDR
	#pragma GCC system_header
	#endif

	#include <bits/requires_hosted.h> // concurrency

	#if __cplusplus < 201103L
	# include <bits/c++0x_warning.h>
	#else

	#if __cplusplus > 201703L
	# include <compare> // std::strong_ordering
	# include <stop_token> // std::stop_source, std::stop_token, std::nostopstate
	#endif

	#include <bits/std_thread.h> // std::thread, get_id, yield
	#include <bits/this_thread_sleep.h> // std::this_thread::sleep_for, sleep_until

	#define __glibcxx_want_jthread
	#define __glibcxx_want_formatters
	#include <bits/version.h>

	#if __cpp_lib_formatters
	# include <format>
	#endif

	namespace std _GLIBCXX_VISIBILITY(default)
	{
	_GLIBCXX_BEGIN_NAMESPACE_VERSION

	/**
	* @defgroup threads Threads
	* @ingroup concurrency
	* @since C++11
	*
	* Classes for thread support.
	* @{
	*/

	// std::thread is defined in <bits/std_thread.h>

	/// @relates std::thread::id @{

	#if __cpp_lib_three_way_comparison
	inline strong_ordering
	operator<=>(thread::id __x, thread::id __y) noexcept
	{ return __x._M_thread <=> __y._M_thread; }
	#else
	inline bool
	operator!=(thread::id __x, thread::id __y) noexcept
	{ return !(__x == __y); }

	inline bool
	operator<(thread::id __x, thread::id __y) noexcept
	{
	// Pthreads doesn't define any way to do this, so we just have to
	// assume native_handle_type is LessThanComparable.
	return __x._M_thread < __y._M_thread;
	}

	inline bool
	operator<=(thread::id __x, thread::id __y) noexcept
	{ return !(__y < __x); }

	inline bool
	operator>(thread::id __x, thread::id __y) noexcept
	{ return __y < __x; }

	inline bool
	operator>=(thread::id __x, thread::id __y) noexcept
	{ return !(__x < __y); }
	#endif // __cpp_lib_three_way_comparison

	template<class _CharT, class _Traits>
	inline basic_ostream<_CharT, _Traits>&
	operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id)
	{
	// Convert non-void pointers to const void* for formatted output.
	using __output_type
	= __conditional_t<is_pointer<thread::native_handle_type>::value,
	const void*,
	thread::native_handle_type>;

	if (__id == thread::id())
	return __out << "thread::id of a non-executing thread";
	else
	return __out << static_cast<__output_type>(__id._M_thread);
	}
	/// @}

	#ifdef __cpp_lib_jthread // C++ >= 20

	/// @cond undocumented
	#ifndef __STRICT_ANSI__
	// As an extension we support invoking a pointer-to-member-function that
	// expects a stop_token as the first argument. See PR libstdc++/100612.
	template<typename _Callable, typename... _Args>
	constexpr bool __pmf_expects_stop_token = false;

	template<typename _Callable, typename _Obj, typename... _Args>
	requires is_member_function_pointer_v<remove_reference_t<_Callable>>
	constexpr bool __pmf_expects_stop_token<_Callable, _Obj, _Args...>
	= is_invocable_v<_Callable, _Obj, stop_token, _Args...>;
	#endif
	/// @endcond

	/** A thread with cancellation and automatic joining.
	*
	* Unlike `std::thread`, destroying a joinable `std::jthread` will not
	* terminate the process. Instead, it will try to request its thread to
	* stop, then will join it.
	*
	* A `std::jthread` has a `std::stop_source` member which will be passed
	* as the first argument to the callable that runs in the new thread
	* (as long as the callable will accept that argument). That can then
	* be used to send a stop request that the new thread can test for.
	*
	* @headerfile thread
	* @since C++20
	*/
	class jthread
	{
	public:
	using id = thread::id;
	using native_handle_type = thread::native_handle_type;

	jthread() noexcept
	: _M_stop_source{nostopstate}
	{ }

	template<typename _Callable, typename... _Args,
	typename = enable_if_t<!is_same_v<remove_cvref_t<_Callable>,
	jthread>>>
	explicit
	jthread(_Callable&& __f, _Args&&... __args)
	: _M_thread{_S_create(_M_stop_source, std::forward<_Callable>(__f),
	std::forward<_Args>(__args)...)}
	{ }

	jthread(const jthread&) = delete;
	jthread(jthread&&) noexcept = default;

	~jthread()
	{
	if (joinable())
	{
	request_stop();
	join();
	}
	}

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

	jthread&
	operator=(jthread&& __other) noexcept
	{
	std::jthread(std::move(__other)).swap(*this);
	return *this;
	}

	void
	swap(jthread& __other) noexcept
	{
	std::swap(_M_stop_source, __other._M_stop_source);
	std::swap(_M_thread, __other._M_thread);
	}

	[[nodiscard]] bool
	joinable() const noexcept
	{
	return _M_thread.joinable();
	}

	void
	join()
	{
	_M_thread.join();
	}

	void
	detach()
	{
	_M_thread.detach();
	}

	[[nodiscard]] id
	get_id() const noexcept
	{
	return _M_thread.get_id();
	}

	[[nodiscard]] native_handle_type
	native_handle()
	{
	return _M_thread.native_handle();
	}

	[[nodiscard]] static unsigned
	hardware_concurrency() noexcept
	{
	return thread::hardware_concurrency();
	}

	[[nodiscard]] stop_source
	get_stop_source() noexcept
	{
	return _M_stop_source;
	}

	[[nodiscard]] stop_token
	get_stop_token() const noexcept
	{
	return _M_stop_source.get_token();
	}

	bool request_stop() noexcept
	{
	return _M_stop_source.request_stop();
	}

	friend void swap(jthread& __lhs, jthread& __rhs) noexcept
	{
	__lhs.swap(__rhs);
	}

	private:
	template<typename _Callable, typename... _Args>
	static thread
	_S_create(stop_source& __ssrc, _Callable&& __f, _Args&&... __args)
	{
	#ifndef __STRICT_ANSI__
	if constexpr (__pmf_expects_stop_token<_Callable, _Args...>)
	return _S_create_pmf(__ssrc, __f, std::forward<_Args>(__args)...);
	else
	#endif
	if constexpr(is_invocable_v<decay_t<_Callable>, stop_token,
	decay_t<_Args>...>)
	return thread{std::forward<_Callable>(__f), __ssrc.get_token(),
	std::forward<_Args>(__args)...};
	else
	{
	static_assert(is_invocable_v<decay_t<_Callable>,
	decay_t<_Args>...>,
	"std::jthread arguments must be invocable after"
	" conversion to rvalues");
	return thread{std::forward<_Callable>(__f),
	std::forward<_Args>(__args)...};
	}
	}

	#ifndef __STRICT_ANSI__
	template<typename _Callable, typename _Obj, typename... _Args>
	static thread
	_S_create_pmf(stop_source& __ssrc, _Callable __f, _Obj&& __obj,
	_Args&&... __args)
	{
	return thread{__f, std::forward<_Obj>(__obj), __ssrc.get_token(),
	std::forward<_Args>(__args)...};
	}
	#endif

	stop_source _M_stop_source;
	thread _M_thread;
	};
	#endif // __cpp_lib_jthread

	#ifdef __cpp_lib_formatters // C++ >= 23
	template<typename _CharT>
	requires is_pointer_v<thread::native_handle_type>
	\|\| is_integral_v<thread::native_handle_type>
	class formatter<thread::id, _CharT>
	{
	public:
	constexpr typename basic_format_parse_context<_CharT>::iterator
	parse(basic_format_parse_context<_CharT>& __pc)
	{
	__format::_Spec<_CharT> __spec{};
	const auto __last = __pc.end();
	auto __first = __pc.begin();

	auto __finalize = [this, &__spec] {
	_M_spec = __spec;
	};

	auto __finished = [&] {
	if (__first == __last \|\| *__first == '}')
	{
	__finalize();
	return true;
	}
	return false;
	};

	if (__finished())
	return __first;

	__first = __spec._M_parse_fill_and_align(__first, __last);
	if (__finished())
	return __first;

	__first = __spec._M_parse_width(__first, __last, __pc);
	if (__finished())
	return __first;

	__throw_format_error("format error: invalid format-spec for "
	"std::thread::id");
	}

	template<typename _Out>
	typename basic_format_context<_Out, _CharT>::iterator
	format(thread::id __id, basic_format_context<_Out, _CharT>& __fc) const
	{
	basic_string_view<_CharT> __sv;
	if constexpr (is_same_v<_CharT, char>)
	__sv = "{}thread::id of a non-executing thread";
	else
	__sv = L"{}thread::id of a non-executing thread";
	basic_string<_CharT> __str;
	if (__id == thread::id())
	__sv.remove_prefix(2);
	else
	{
	using _FmtStr = __format::_Runtime_format_string<_CharT>;
	// Convert non-void pointers to const void* for formatted output.
	using __output_type
	= __conditional_t<is_pointer_v<thread::native_handle_type>,
	const void*,
	thread::native_handle_type>;
	auto __o = static_cast<__output_type>(__id._M_thread);
	__sv = __str = std::format(_FmtStr(__sv.substr(0, 2)), __o);
	}
	return __format::__write_padded_as_spec(__sv, __sv.size(),
	__fc, _M_spec,
	__format::_Align_right);
	}

	private:
	__format::_Spec<_CharT> _M_spec;
	};
	#endif // __cpp_lib_formatters

	/// @} group threads

	_GLIBCXX_END_NAMESPACE_VERSION
	} // namespace
	#endif // C++11
	#endif // _GLIBCXX_THREAD