Are there any performance implications of using references in PHP functions?

Using references in PHP functions can have performance implications, as passing variables by reference can consume more memory and processing power compared to passing variables by value. To optimize performance, it is recommended to only use references when necessary, such as when you need to modify the original variable within a function.

// Example of using references in a PHP function
function modifyValue(&$value) {
    $value += 10;
}

$num = 5;
modifyValue($num);
echo $num; // Output: 15