Task-based concurrency is a programming paradigm that allows developers to write
concurrent code by specifying tasks (i.e., units of work) that can be executed in
parallel, rather than explicitly managing threads and synchronization mechanisms.

The C++17 standard introduced the std::jthread class which is a C++20 task-based 
concurrency library. The std::jthread class is a drop-in replacement for
std::thread with the added benefit that it can automatically join the thread when
it goes out of scope.

Here is an example of using std::jthread to launch a function in a separate thread:

Copy code
#include <iostream>
#include <jthread>

void long_running_task() {
    std::cout << "Performing long-running task..." << std::endl;
    std::this_thread::sleep_for(std::chrono::seconds(5));
    std::cout << "Task complete." << std::endl;
}

int main() {
    std::cout << "Starting long-running task..." << std::endl;
    std::jthread t(long_running_task); 
    std::cout << "Doing other work while the task runs..." << std::endl;
    // ...
    // The thread will be automatically joined when t goes out of scope
    std::cout << "Retrieving result of long-running task..." << std::endl;
    std::cout << "Result of long-running task: " << std::endl;
    return 0;
}
The above code is similar to the previous example, but with the std::jthread class,
you don't need to explicitly call join() function to wait for the thread to
complete its execution. The thread will be automatically joined when the 
std::jthread object goes out of scope.

Please let me know if you need more information on task-based concurrency or the
std::jthread class.