试图了解C ++中的线程

Question

I am a C# programmer and i need to create a program in c++ now. What i'm trying to achieve is make an infinite thread and give it a sleep time.

In c# i could easily do this like

in main function

new Thread(taskfunction).Start();

and taskfunction

    private void taskfunction()
    {
    while(true){Thread.Sleep(2500); // do stuff}
    }

so this would work in the background as long as my program is on. I am trying to achieve the same thing in c++ like:

in main function

std::thread somethread(taskfunction);
somethread.join();

and taskfunction

void taskfunction()
{
while(true){this_thread::sleep_for(chrono::milliseconds(2500));// Do Stuff}
}

So, while c# thread starts and moves on, c++ thread waits on somethread.join(); . What is the difference and How can i achieve what i do in c# also in c++?

Thank you

Answer 1

std::thread::join() block current thread of execution until thread, that you call it on, finishes it execution (returns from thread procedure).

This is useful, if (for example) you want to create temporary threads, that should perform some computations and generate results, that you wait on and use immediately.

In your case, you should not use this method - at least not immediately after thread's creation. Note, however, that std::thread must be either joined or detached:

std::thread::~thread()

Destroys the thread object.

If *this has an associated thread ( joinable() == true ), std::terminate() is called.

So you need to either:

• detach() thread if it should be executed independently from main thread (resources allocated by thread will be automatically released when thread finishes its execution)
• proceed in main() and when you reach end of your program, signal thread, that it should end and then join() it.

Answer 2

您可以detach()线程使其独立。

Answer 3

use std::tread::detach(). this function separates the thread of execution from the thread object, allowing execution to continue independently. Any allocated resources will be freed once the thread exits.