operator==,!=,<,<=,>,>=,<=>(std::thread::id)

 

C++

编译器支持

自立实现与有宿主实现

语言

标准库

标准库标头

具名要求

功能特性测试宏 (C++20)

语言支持库

概念库 (C++20)

元编程库 (C++11)

诊断库

通用工具库

字符串库

容器库

迭代器库

范围库 (C++20)

算法库

数值库

本地化库

输入/输出库

文件系统库 (C++17)

正则表达式库 (C++11)

并发支持库 (C++11)

技术规范

符号索引

外部库

 

并发支持库

线程 thread (C++11) jthread (C++20) stop_token (C++20) stop_source (C++20) stop_callback (C++20) hardware_destructive_interference_sizehardware_constructive_interference_size (C++17)(C++17) this_thread 命名空间 get_id (C++11) yield (C++11) sleep_for (C++11) sleep_until (C++11) 互斥 mutex (C++11) recursive_mutex (C++11)   shared_mutex (C++17) timed_mutex (C++11) recursive_timed_mutex (C++11)     shared_timed_mutex (C++14) 通用锁管理 lock (C++11) lock_guard (C++11) scoped_lock (C++17) unique_lock (C++11) shared_lock (C++14) once_flag (C++11) call_once (C++11) try_lock (C++11) defer_locktry_to_lockadopt_lockdefer_lock_ttry_to_lock_tadopt_lock_t (C++11)(C++11)(C++11)(C++11)(C++11)(C++11) 条件变量 condition_variable (C++11) condition_variable_any (C++11) notify_all_at_thread_exit (C++11) cv_status (C++11) 信号量 counting_semaphorebinary_semaphore (C++20)(C++20) 闩与屏障 latch (C++20) barrier (C++20) 未来体 promise (C++11) future (C++11) shared_future (C++11) packaged_task (C++11) async (C++11) launch (C++11) future_status (C++11) future_error (C++11) future_category (C++11) future_errc (C++11) 安全回收 rcu_obj_base (C++26) rcu_domain (C++26) rcu_default_domain (C++26)   rcu_synchronize (C++26) rcu_barrier (C++26) rcu_retire (C++26) 风险指针 hazard_pointer_obj_base (C++26) hazard_pointer (C++26) make_hazard_pointer (C++26)

原子类型 atomic (C++11) atomic_ref (C++20) atomic_flag (C++11) 原子类型的初始化 atomic_init (C++11)(C++20 中弃用) ATOMIC_VAR_INIT (C++11)(C++20 中弃用) ATOMIC_FLAG_INIT (C++11) 内存定序 memory_order (C++11) kill_dependency (C++11) atomic_thread_fence (C++11) atomic_signal_fence (C++11) 原子操作的自由函数 atomic_storeatomic_store_explicit (C++11)(C++11) atomic_loadatomic_load_explicit (C++11)(C++11) atomic_exchangeatomic_exchange_explicit (C++11)(C++11) atomic_compare_exchange_weakatomic_compare_exchange_weak_explicitatomic_compare_exchange_strongatomic_compare_exchange_strong_explicit (C++11)(C++11)(C++11)(C++11) atomic_fetch_addatomic_fetch_add_explicit (C++11)(C++11) atomic_fetch_subatomic_fetch_sub_explicit (C++11)(C++11) atomic_fetch_andatomic_fetch_and_explicit (C++11)(C++11) atomic_fetch_oratomic_fetch_or_explicit (C++11)(C++11) atomic_fetch_xoratomic_fetch_xor_explicit (C++11)(C++11) atomic_fetch_maxatomic_fetch_max_explicit (C++26)(C++26) atomic_fetch_minatomic_fetch_min_explicit (C++26)(C++26) atomic_is_lock_free (C++11) atomic_waitatomic_wait_explicit (C++20)(C++20) atomic_notify_one (C++20) atomic_notify_all (C++20) 原子标志的自由函数 atomic_flag_test_and_setatomic_flag_test_and_set_explicit (C++11)(C++11) atomic_flag_clearatomic_flag_clear_explicit (C++11)(C++11) atomic_flag_testatomic_flag_test_explicit (C++20)(C++20) atomic_flag_waitatomic_flag_wait_explicit (C++20)(C++20) atomic_flag_notify_one (C++20) atomic_flag_notify_all (C++20)

 

std::thread

成员类

thread::id

成员函数

thread::thread

thread::~thread

thread::operator=

观察器

thread::joinable

thread::get_id

thread::native_handle

thread::hardware_concurrency

操作

thread::join

thread::detach

thread::swap

非成员函数

swap(std::thread)

 

std::thread::id

成员函数

id::id

非成员函数

operator==operator!=operator<operator<=operator>operator>=operator<=> (C++20 前)(C++20 前)(C++20 前)(C++20 前)(C++20 前)(C++20)

operator<<

辅助类

hash<std::thread::id>

formatter<std::thread::id> (C++23)

 

在标头 <thread> 定义
bool operator==( std::thread::id lhs, std::thread::id rhs ) noexcept;	(1)	(C++11 起)
bool operator!=( std::thread::id lhs, std::thread::id rhs ) noexcept;	(2)	(C++11 起) (C++20 前)
bool operator< ( std::thread::id lhs, std::thread::id rhs ) noexcept;	(3)	(C++11 起) (C++20 前)
bool operator<=( std::thread::id lhs, std::thread::id rhs ) noexcept;	(4)	(C++11 起) (C++20 前)
bool operator> ( std::thread::id lhs, std::thread::id rhs ) noexcept;	(5)	(C++11 起) (C++20 前)
bool operator>=( std::thread::id lhs, std::thread::id rhs ) noexcept;	(6)	(C++11 起) (C++20 前)
std::strong_ordering operator<=>( std::thread::id lhs,                                   std::thread::id rhs ) noexcept;	(7)	(C++20 起)

比较两个线程标识符。

1,2) 检查 lhs 与 rhs 是否表示同一线程或均不表示线程。

3-7) 在未指明的全序中比较 lhs 与 rhs。

<、<=、>、>= 及 != 运算符分别从 operator<=> 与 operator== 合成。

(C++20 起)

参数

lhs, rhs

-

要比较的线程标识符

返回值

1-6) 若相应的关系成立则为 true，否则为 false。

7) 若在该全序中 lhs 小于 rhs 则为 std::strong_ordering::less；否则若在该全序中 rhs 小于 lhs 则为 std::strong_ordering::greater ；否则为 std::strong_ordering::equal。

复杂度

常数。

示例

运行此代码

#include <cassert>
#include <chrono>
#include <iostream>
#include <thread>
 
 
int main()
{
    auto work = [] { std::this_thread::sleep_for(std::chrono::seconds(1)); };
    std::thread t1(work);
    std::thread t2(work);
 
    assert(t1.get_id() == t1.get_id() and
           t2.get_id() == t2.get_id() and
           t1.get_id() != t2.get_id());
 
    if (const auto cmp = t1.get_id() <=> t2.get_id(); cmp < 0)
        std::cout << "id1 < id2\n";
    else
        std::cout << "id1 > id2\n";
 
    std::cout << "id1: " << t1.get_id() << "\n"
                 "id2: " << t2.get_id() << '\n';
 
    t1.join();
    t2.join();
}

可能的输出：

id1 > id2
id1: 139741717640896
id2: 139741709248192