How can PHP extensions like mcal impact the functionality of certain functions and what steps should be taken to ensure proper usage?

PHP extensions like mcal can impact the functionality of certain functions by overriding or extending their behavior. To ensure proper usage, it is important to carefully read the documentation of the extension and understand how it interacts with the functions you are using. Additionally, you should test your code thoroughly to ensure that the extension does not cause any unexpected behavior.

// Example code snippet demonstrating proper usage of the mcal extension
if (extension_loaded('mcal')) {
    // Use mcal functions here
    // Make sure to follow the documentation and handle any potential conflicts with other functions
} else {
    // Handle the case where the mcal extension is not loaded
    echo "mcal extension is not loaded.";
}