std::thread::join

 

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线程 thread (C++11) jthread (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) 协同取消 stop_token (C++20) inplace_stop_token (C++26) never_stop_token (C++26) stop_source (C++20) inplace_stop_source (C++26)   stop_callback (C++20) inplace_stop_callback (C++26) stop_callback_for_t (C++26) stoppable_token (C++26) unstoppable_token (C++26) stoppable-source (C++26) stoppable-callback-for (C++26)   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) 门闩和屏障 latch (C++20) barrier (C++20) 期值 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) 危险指针 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 中已弃用) ATOMIC_VAR_INIT (C++11)(C++20 中已弃用) ATOMIC_FLAG_INIT (C++11) 内存排序 memory_order (C++11) kill_dependency (C++11)(C++26 中已弃用) 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) (C++11)

 

void join();		(C++11 起)

阻塞当前线程，直到由 *this 标识的线程执行完毕。

由 *this 标识的线程的完成与 join() 相应的成功返回“同步”。

对 *this 本身不执行同步。从多个线程并发地对同一个线程对象调用 join() 会导致数据竞争，从而导致未定义行为。

参数

(无)

返回值

(无)

后置条件

joinable() 为 false。

异常

如果发生错误，则抛出 std::system_error。

错误条件

• 如果 this->get_id() == std::this_thread::get_id()（检测到死锁），则为 resource_deadlock_would_occur。
• 如果线程无效，则为 no_such_process。
• 如果 joinable() 为 false，则为 invalid_argument。

示例

运行此代码

#include <chrono>
#include <iostream>
#include <thread>
 
void foo()
{
    // simulate expensive operation
    std::this_thread::sleep_for(std::chrono::seconds(1));
}
 
void bar()
{
    // simulate expensive operation
    std::this_thread::sleep_for(std::chrono::seconds(1));
}
 
int main()
{
    std::cout << "starting first helper...\n";
    std::thread helper1(foo);
 
    std::cout << "starting second helper...\n";
    std::thread helper2(bar);
 
    std::cout << "waiting for helpers to finish..." << std::endl;
    helper1.join();
    helper2.join();
 
    std::cout << "done!\n";
}

输出

starting first helper...
starting second helper...
waiting for helpers to finish...
done!

参考

• C++23 标准 (ISO/IEC 14882:2024)

• 33.4.3.6 成员 [thread.thread.member]

• C++20 标准 (ISO/IEC 14882:2020)

• 32.4.2.5 成员 [thread.thread.member]

• C++17 标准 (ISO/IEC 14882:2017)

• 33.3.2.5 线程成员 [thread.thread.member]

• C++14 标准 (ISO/IEC 14882:2014)

• 30.3.1.5 线程成员 [thread.thread.member]

• C++11 标准 (ISO/IEC 14882:2011)

• 30.3.1.5 线程成员 [thread.thread.member]

另请参阅

detach	允许线程独立于线程句柄执行 (公共成员函数)
joinable	检查线程是否可join，即是否可能在并行上下文中运行 (公共成员函数)
C 文档 关于 thrd_join