With the release of C++20, a new addition to the Standard Library is the std::jthread class. std::jthread is a lightweight wrapper around std::thread that provides the ability to join or detach the underlying thread automatically when the std::jthread object goes out of scope. This can be useful in scenarios where you want to ensure proper thread management without explicit calls to join or detach.

Let’s take a look at an example code snippet to demonstrate the usage of std::jthread:

#include <iostream>
#include <thread>
#include <chrono>

void foo() {
    for (int i = 0; i < 5; ++i) {
        std::cout << "Executing foo: " << i << std::endl;
        std::this_thread::sleep_for(std::chrono::seconds(1));
    }
}

int main() {
    std::cout << "Main thread started" << std::endl;

    std::jthread t(foo);

    std::cout << "Main thread doing some work..." << std::endl;
    std::this_thread::sleep_for(std::chrono::seconds(3));

    std::cout << "Main thread finished" << std::endl;

    return 0;
}

In this example, we define a function foo that simply prints a message and waits for 1 second. We then create an instance of std::jthread named t that takes foo as its callable parameter. This means foo will be executed in a separate thread.

After creating the std::jthread object, the main thread carries on with some other work for 3 seconds before completing. When the std::jthread object t goes out of scope at the end of the main function, it automatically joins the underlying thread, ensuring that foo completes its execution before the program exits.

This automatic joining behavior of std::jthread eliminates the need for explicit calls to join or detach, making the code more concise and less error-prone.

Overall, std::jthread brings convenience and simplicity to thread management in C++ by providing automatic thread joining. It is a valuable addition to the Standard Library, making it easier to write clean and reliable multithreaded code.

#cplusplus #multithreading