Implementing timeouts with std::chrono

20 Oct 2023

stdchrono

Sometimes when writing code, you may need to set a timeout for certain operations. This can be useful to prevent your program from hanging indefinitely if a task takes too long to complete. In C++, you can use the std::chrono library to easily implement timeouts in a platform-independent way.

Using std::chrono for timeouts

The std::chrono library provides various classes and functions for working with time durations and time points. To implement timeouts, we can make use of the std::chrono::system_clock and std::chrono::duration classes.

Here’s an example of how you can use std::chrono to implement a timeout for a function:

#include <chrono>
#include <future>
#include <iostream>

// Function to be called with a timeout
int calculateSquare(int num)
{
    std::this_thread::sleep_for(std::chrono::seconds(5)); // Simulating a long-running operation
    return num * num;
}

int main()
{
    // Start a new thread to execute the function
    std::future<int> result = std::async(std::launch::async, calculateSquare, 5);

    // Wait for the result with a timeout
    if (result.wait_for(std::chrono::seconds(3)) == std::future_status::ready) {
        // The result is available
        std::cout << "Result: " << result.get() << std::endl;
    } else {
        // The timeout was reached
        std::cout << "Timeout reached!" << std::endl;
    }

    return 0;
}

In this example, we have a function calculateSquare that takes an integer and returns its square after a simulated long-running operation. We launch this function asynchronously in a separate thread using std::async. Then, we use std::future::wait_for to wait for the result, specifying a timeout duration of 3 seconds. If the result is available before the timeout, we retrieve it using std::future::get. Otherwise, we handle the timeout accordingly.

Conclusion

By using the std::chrono library in C++, you can easily implement timeouts for your code. This not only prevents your program from hanging indefinitely but also provides a way to handle long-running operations gracefully. With std::chrono, you have a powerful and flexible tool for managing time-related operations in your C++ programs.

Using std::chrono for timeouts

Conclusion

References