用于创建线程并以可变数量的线程加入的循环 [英] Loop for creating threads and joining with variable number of threads

问题描述

我正在构建一个程序，出于测试目的，该程序可以在C ++中创建N个线程.我是C ++的相对新手，到目前为止，我目前的尝试是

I am building a program that, for testing purposes can create N number of threads in C++. I am relativity new to C++ and my current attempt so far is

//Create a list of threads
std::vector<std::thread> t;
for(i=0; i < THREADS; i ++){
    std::thread th = std::thread([](){ workThreadProcess(); });
    t.push_back(th);
    printf("Thread started \n");
    }

for(std::thread th : t){
    th.join();
}

我当前遇到一个错误，该错误表明调用了已删除的'std :: thread'构造函数.我不知道这意味着什么或如何修复

I currently an error that says call to deleted constructor of 'std::thread'. I am unusre what this means or how to fix in

注意:
我看过:

Note:
I have looked at:

• 创建可变数量的std :: threads
• 可变的c ++线程数
• 数组线程并尝试将多个参数传递给函数不起作用?
• std :: threads的向量
• 创建N个线程

但是我不觉得他们回答了我的问题.他们大多数使用pthreads或其他构造函数.

But I don't feel they answer my question. Most of them use pthreads or a a different constructor.

推荐答案

您无法复制线程.您需要移动它们才能使其进入向量.同样，您不能在循环中创建临时副本以将它们加入:您必须使用引用.

You can't copy threads. You need to move them in order to get them into the vector. Also, you can't create temporary copies in the loop to join them: you have to use a references instead.

这是一个有效的版本

std::vector<std::thread> t;
for(int i=0; i < THREADS; i ++){
    std::thread th = std::thread([](){ workThreadProcess(); });
    t.push_back(std::move(th));  //<=== move (after, th doesn't hold it anymore 
    std::cout<<"Thread started"<<std::endl;
    }

for(auto& th : t){              //<=== range-based for uses & reference
    th.join();
}

在线演示

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