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c++11标准库新增的thread类开始执行的时间?

请问一下C++11中<thread>的,thread具体是什么时候执行赋予它的函数?
相关代码如下:

#include <iostream>
#include <thread>

void hello()
{
    std::cout << "Hello Current World!" << std::endl;
}

int main()
{
    std::thread t(hello);
    std::cout << "before: " << std::endl;
    t.join();
    std::cout << "after: "  << std::endl;
    return 0 ;
}

在windows平台上,IDE DEV-C++,编译器TDM-GCC 5.10,执行程序的结果有可能为



在linux(ubuntu)上,编译器g++ (Ubuntu 5.3.1-14ubuntu2.1) 5.3.1 20160413
执行程序执行了20~30遍一直是

也曾经尝试过直接把t.join()直接注释掉,两个平台都会崩溃,但是windows还是会先输出Hello Current World!之后崩溃,而linux只输出了before和after

看过cppreference里面相关的内容,好像是说在构造函数如果有赋予入口函数的话就会直接开始执行?不过linux里面好像是直到调用join函数或者detach函数才会开始执行?

ringa_leeringa_lee2765 days ago680

reply all(2)I'll reply

  • 阿神

    阿神2017-04-17 14:00:33

    If you pass in the routine to be executed in the constructor, the thread will start executing after the thread object is created. If you just create a thread object:

    thread t;
    

    Then this thread will not start until you assign a routine to this object. The reason why
    crashes is that if the thread object does not join or detach before is destructed , then std::terminate will be called to terminate the program (you can look at the destructor implementation of thread), GCC Implementation of:

     ~thread()
        {
          if (joinable())
              std::terminate();
        }
    

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  • 天蓬老师

    天蓬老师2017-04-17 14:00:33

    Add a line get char()

    The child threads are not running, and the main thread has exited.

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