C++11: async vs thread

What are the main differences between async and thread in C++11?

In C++11, std::async is used for asynchronous operations, while std::thread is for creating threads. async can return a future, allowing you to retrieve the result later, whereas thread runs a function concurrently without returning a value.

When should I use async instead of thread?

Use async when you want to run a task in the background and retrieve its result later. It's simpler for tasks that can be executed asynchronously. Use thread for more control over thread management.

Can you give an example of using async?

Sure! Here's a simple example:

#include <future>
#include <iostream>

int compute() {
    return 42;
}

int main() {
    std::future<int> result = std::async(compute);
    std::cout << "Result: " << result.get() << std::endl;
}
``` This runs `compute` asynchronously and retrieves the result.

Are there any downsides to using async?

Yes, using async can lead to overhead due to managing futures and may not be as efficient for very lightweight tasks. Additionally, if the task is not executed, it can lead to unexpected behavior.