C++: Async vs Threads

What are the main differences between async and threads in C++?

In C++, async allows you to run tasks asynchronously, while threads provide a way to run tasks concurrently. Async is generally easier to use and manage, as it abstracts away some of the complexities of thread management.

When should I use async instead of threads?

You should use async when you want to perform non-blocking operations, like I/O tasks, without managing thread lifecycles. It's ideal for tasks that can be executed in the background without needing direct control over the threads.

Can you give an example of using async in C++?

Sure! Here's a simple example:

#include <future>
#include <iostream>

int asyncTask() {
    // Simulate a long-running task
    std::this_thread::sleep_for(std::chrono::seconds(2));
    return 42;
}

int main() {
    std::future<int> result = std::async(std::launch::async, asyncTask);
    std::cout << "Waiting for result..." << std::endl;
    std::cout << "Result: " << result.get() << std::endl;
}

What are the performance implications of using async vs threads?

Async can be more efficient for I/O-bound tasks since it doesn't require the overhead of managing multiple threads. However, for CPU-bound tasks, using threads might yield better performance as they can utilize multiple cores effectively.