How to close thread detach C++?

Question

I launched thread as detach. How to close thread from main function?

void My()
{
   // actions  
}


void main()
{

    std::thread thr7(receive);
    thr         


        

Answer 1

Short Answer:

Use a shared variable to signal threads when to stop.

Long answer:

You cannot call join or terminate a thread directly from its parent once detach is called unless you use some other methods.

Take a look at the following code (over simple and not very meaninful) which should show a simple way of doing what you are asking:

#include 
#include 
#include 
#include 
#include 
#include 
#include 

std::mutex mu;
std::condition_variable cv;
bool finished = false;

void threadFunc()
{
    while(!finished)
    {
        
        std:: cout << "Thread doing work \n";
        std::this_thread::sleep_for(std::chrono::milliseconds(5));
    }
    
    std::cout << "End of Thread \n";
}

int main()
{

    {
        std::thread t1(threadFunc);
        t1.detach(); // Call `detach` to prevent blocking this thread

    } // Need to call `join` or `detach` before `thread` goes out of scope

    for (int i = 0; i < 5; ++i){
        std::this_thread::sleep_for(std::chrono::milliseconds(20));
        std::cout << "Main doing stuff: \n";
    }
    std::cout << "Terminating the thread\n";

    std::unique_lock lock(mu);  
    finished = true;
    cv.notify_all();
    std::cout << "End of Main\n";
    return 0;
}

You use a shared variable to tell the threads when to terminate its execution.