std::thread::join

 

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std::thread

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thread::id

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thread::thread

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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

std::swap

 

void join();		(C++11 起)

阻塞当前线程，直至 *this 所标识的线程完成其执行。

*this 所标识的线程的完成同步于从 join() 的成功返回。

参数

（无）

返回值

（无）

后置条件

joinable 为 false

异常

若错误发生则为 std::system_error 。

错误条件

• 若 this->get_id() == std::this_thread::get_id() （检测到死锁）则为 resource_deadlock_would_occur
• 若线程非法则为 no_such_process
• 若 joinable 为 false 则为 invalid_argument

示例

运行此代码

#include <iostream>
#include <thread>
#include <chrono>
 
void foo()
{
    // 模拟昂贵操作
    std::this_thread::sleep_for(std::chrono::seconds(1));
}
 
void bar()
{
    // 模拟昂贵操作
    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!

引用

• C++11 standard (ISO/IEC 14882:2011):

• 30.3.1.5 thread members [thread.thread.member]

参阅

detach	容许线程从线程句柄独立开来执行 (公开成员函数)
joinable	检查线程是否可合并，即潜在地运行于平行环境中 (公开成员函数)
thrd_join 的 C 文档