libcxx/include/__thread/id.h

   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/hash.h>
  16 #include <__fwd/ostream.h>
  17 #include <__threading_support>
  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 #ifndef _LIBCPP_HAS_NO_THREADS
  26 class _LIBCPP_EXPORTED_FROM_ABI __thread_id;
  27
  28 namespace this_thread {
  29
  30 _LIBCPP_HIDE_FROM_ABI __thread_id get_id() _NOEXCEPT;
  31
  32 } // namespace this_thread
  33
  34 template <>
  35 struct hash<__thread_id>;
  36
  37 class _LIBCPP_TEMPLATE_VIS __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
  52 public:
  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
  68 private:
  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 _LIBCPP_TEMPLATE_VIS hash<__thread_id>;
  76 };
  77
  78 inline _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
  89 inline _LIBCPP_HIDE_FROM_ABI bool operator!=(__thread_id __x, __thread_id __y) _NOEXCEPT { return !(__x == __y); }
  90
  91 inline _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
  95 inline _LIBCPP_HIDE_FROM_ABI bool operator<=(__thread_id __x, __thread_id __y) _NOEXCEPT { return !(__y < __x); }
  96 inline _LIBCPP_HIDE_FROM_ABI bool operator>(__thread_id __x, __thread_id __y) _NOEXCEPT { return __y < __x; }
  97 inline _LIBCPP_HIDE_FROM_ABI bool operator>=(__thread_id __x, __thread_id __y) _NOEXCEPT { return !(__x < __y); }
  98
  99 #  else // _LIBCPP_STD_VER <= 17
 100
 101 inline _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
 111 namespace this_thread {
 112
 113 inline _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_NO_THREADS
 118
 119 _LIBCPP_END_NAMESPACE_STD
 120
 121 #endif // _LIBCPP___THREAD_ID_H