1// -*- C++ -*-
  2//===----------------------------------------------------------------------===//
  3//
  4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  5// See https://llvm.org/LICENSE.txt for license information.
  6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  7//
  8//===----------------------------------------------------------------------===//
  9
 10#ifndef _LIBCPP___THREAD_ID_H
 11#define _LIBCPP___THREAD_ID_H
 12
 13#include <__compare/ordering.h>
 14#include <__config>
 15#include <__fwd/functional.h>
 16#include <__fwd/ostream.h>
 17#include <__thread/support.h>
 18
 19#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 20#  pragma GCC system_header
 21#endif
 22
 23_LIBCPP_BEGIN_NAMESPACE_STD
 24
 25#if _LIBCPP_HAS_THREADS
 26class _LIBCPP_EXPORTED_FROM_ABI __thread_id;
 27
 28namespace this_thread {
 29
 30_LIBCPP_HIDE_FROM_ABI __thread_id get_id() _NOEXCEPT;
 31
 32} // namespace this_thread
 33
 34template <>
 35struct hash<__thread_id>;
 36
 37class __thread_id {
 38  // FIXME: pthread_t is a pointer on Darwin but a long on Linux.
 39  // NULL is the no-thread value on Darwin.  Someone needs to check
 40  // on other platforms.  We assume 0 works everywhere for now.
 41  __libcpp_thread_id __id_;
 42
 43  static _LIBCPP_HIDE_FROM_ABI bool
 44  __lt_impl(__thread_id __x, __thread_id __y) _NOEXCEPT { // id==0 is always less than any other thread_id
 45    if (__x.__id_ == 0)
 46      return __y.__id_ != 0;
 47    if (__y.__id_ == 0)
 48      return false;
 49    return __libcpp_thread_id_less(__x.__id_, __y.__id_);
 50  }
 51
 52public:
 53  _LIBCPP_HIDE_FROM_ABI __thread_id() _NOEXCEPT : __id_(0) {}
 54
 55  _LIBCPP_HIDE_FROM_ABI void __reset() { __id_ = 0; }
 56
 57  friend _LIBCPP_HIDE_FROM_ABI bool operator==(__thread_id __x, __thread_id __y) _NOEXCEPT;
 58#  if _LIBCPP_STD_VER <= 17
 59  friend _LIBCPP_HIDE_FROM_ABI bool operator<(__thread_id __x, __thread_id __y) _NOEXCEPT;
 60#  else  // _LIBCPP_STD_VER <= 17
 61  friend _LIBCPP_HIDE_FROM_ABI strong_ordering operator<=>(__thread_id __x, __thread_id __y) noexcept;
 62#  endif // _LIBCPP_STD_VER <= 17
 63
 64  template <class _CharT, class _Traits>
 65  friend _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
 66  operator<<(basic_ostream<_CharT, _Traits>& __os, __thread_id __id);
 67
 68private:
 69  _LIBCPP_HIDE_FROM_ABI __thread_id(__libcpp_thread_id __id) : __id_(__id) {}
 70
 71  _LIBCPP_HIDE_FROM_ABI friend __libcpp_thread_id __get_underlying_id(const __thread_id __id) { return __id.__id_; }
 72
 73  friend __thread_id this_thread::get_id() _NOEXCEPT;
 74  friend class _LIBCPP_EXPORTED_FROM_ABI thread;
 75  friend struct hash<__thread_id>;
 76};
 77
 78inline _LIBCPP_HIDE_FROM_ABI bool operator==(__thread_id __x, __thread_id __y) _NOEXCEPT {
 79  // Don't pass id==0 to underlying routines
 80  if (__x.__id_ == 0)
 81    return __y.__id_ == 0;
 82  if (__y.__id_ == 0)
 83    return false;
 84  return __libcpp_thread_id_equal(__x.__id_, __y.__id_);
 85}
 86
 87#  if _LIBCPP_STD_VER <= 17
 88
 89inline _LIBCPP_HIDE_FROM_ABI bool operator!=(__thread_id __x, __thread_id __y) _NOEXCEPT { return !(__x == __y); }
 90
 91inline _LIBCPP_HIDE_FROM_ABI bool operator<(__thread_id __x, __thread_id __y) _NOEXCEPT {
 92  return __thread_id::__lt_impl(__x.__id_, __y.__id_);
 93}
 94
 95inline _LIBCPP_HIDE_FROM_ABI bool operator<=(__thread_id __x, __thread_id __y) _NOEXCEPT { return !(__y < __x); }
 96inline _LIBCPP_HIDE_FROM_ABI bool operator>(__thread_id __x, __thread_id __y) _NOEXCEPT { return __y < __x; }
 97inline _LIBCPP_HIDE_FROM_ABI bool operator>=(__thread_id __x, __thread_id __y) _NOEXCEPT { return !(__x < __y); }
 98
 99#  else // _LIBCPP_STD_VER <= 17
100
101inline _LIBCPP_HIDE_FROM_ABI strong_ordering operator<=>(__thread_id __x, __thread_id __y) noexcept {
102  if (__x == __y)
103    return strong_ordering::equal;
104  if (__thread_id::__lt_impl(__x, __y))
105    return strong_ordering::less;
106  return strong_ordering::greater;
107}
108
109#  endif // _LIBCPP_STD_VER <= 17
110
111namespace this_thread {
112
113inline _LIBCPP_HIDE_FROM_ABI __thread_id get_id() _NOEXCEPT { return __libcpp_thread_get_current_id(); }
114
115} // namespace this_thread
116
117#endif // _LIBCPP_HAS_THREADS
118
119_LIBCPP_END_NAMESPACE_STD
120
121#endif // _LIBCPP___THREAD_ID_H