C++ Error Handling with Futures

What are futures in C++ and how do they help with error handling?

Futures in C++ are a way to handle asynchronous operations. They allow you to retrieve results from operations that may not have completed yet, and they can also help manage errors by providing a mechanism to check if an operation failed.

Can you give me an example of using futures for error handling?

Sure! Here's a simple example:

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

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

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

This code demonstrates how to catch exceptions thrown by a function executed asynchronously.

What happens if I don't handle the exception from the future?

If you don't handle the exception, it will propagate to the calling thread when you call get(), potentially causing your program to terminate unexpectedly. It's important to always handle exceptions when working with futures.

Are there any best practices for using futures in C++?

Yes, some best practices include:

1. Always check for exceptions using get().
2. Use std::launch::async to ensure tasks run in separate threads.
3. Avoid sharing futures across threads to prevent data races.