How do I handle errors in C++14 async libraries?

How do I handle errors in C++14 async libraries?

In C++14, you can handle errors in async libraries using futures and exceptions. When a task fails, it can throw an exception that you can catch when you retrieve the result.

Can you give me an example of that?

Sure! Here's a simple example:

#include <future>
#include <iostream>
#include <stdexcept>

int riskyTask() {
    throw std::runtime_error("Something went wrong!");
}

int main() {
    std::future<int> result = std::async(riskyTask);
    try {
        result.get(); // This will throw the exception
    } catch (const std::exception& e) {
        std::cout << "Error: " << e.what() << std::endl;
    }
}

What if I want to handle multiple async tasks?

You can use std::when_all to wait for multiple futures and handle exceptions for each one individually. Here's an example:

#include <future>
#include <iostream>
#include <vector>

int task(int id) {
    if (id % 2 == 0) throw std::runtime_error("Error in task " + std::to_string(id));
    return id;
}

int main() {
    std::vector<std::future<int>> futures;
    for (int i = 0; i < 5; ++i) {
        futures.push_back(std::async(task, i));
    }
    for (auto& fut : futures) {
        try {
            std::cout << "Result: " << fut.get() << std::endl;
        } catch (const std::exception& e) {
            std::cout << "Caught: " << e.what() << std::endl;
        }
    }
}