Custom time literals in C++

23 Oct 2023

In C++, you can define your own time literals by overloading the existing ones or creating new ones. Time literals are used to represent time durations in a more readable and expressive way.

Let’s say you want to define a custom time literal for representing milliseconds. Here’s an example of how you can achieve this:

#include <chrono>

constexpr std::chrono::milliseconds operator"" _ms(unsigned long long milliseconds)
{
    return std::chrono::milliseconds(milliseconds);
}

In the code above, we define a user-defined literal operator"" _ms that takes an unsigned long long value representing the number of milliseconds. It returns a std::chrono::milliseconds object representing the duration.

Now, you can use the custom time literal 300_ms to represent 300 milliseconds in your code:

#include <iostream>

int main()
{
    auto duration = 300_ms;
    std::cout << duration.count() << " milliseconds\n"; // Output: 300 milliseconds

    return 0;
}

The count() member function returns the number of milliseconds in the duration.

You can similarly define custom time literals for other time units such as seconds, minutes, hours, etc. This allows you to write more expressive and readable code when working with time durations.

Benefits of custom time literals

Using custom time literals can provide the following benefits:

Readability: Custom time literals make your code more expressive and self-explanatory, as the time durations are represented in a human-friendly format.
Compile-time checking: By using user-defined literals, the compiler ensures that the time literals are used correctly and type-safe at compile-time. This reduces the chances of bugs related to incorrect time unit conversions.
Integration with standard library: Custom time literals seamlessly integrate with the standard <chrono> library, allowing you to use them in various time-related operations and calculations.
Consistency: By defining custom time literals, you can ensure that your codebase follows a consistent time unit convention throughout, making it easier to understand and maintain.

Overall, custom time literals in C++ help improve code readability and maintainability when working with time durations, enabling you to write more concise and understandable code.

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