What potential pitfalls should be considered when using usort to sort arrays in PHP?

One potential pitfall when using usort to sort arrays in PHP is that the comparison function used may not always return consistent results, leading to unexpected sorting outcomes. To avoid this, ensure that the comparison function is well-defined and returns a consistent value for all inputs. Additionally, be cautious of potential performance issues when sorting large arrays, as usort may not be the most efficient sorting method in such cases.

// Example of a well-defined and consistent comparison function for usort
function customSort($a, $b) {
    if ($a == $b) {
        return 0;
    }
    return ($a < $b) ? -1 : 1;
}

// Usage of usort with the custom comparison function
$array = [3, 1, 2];
usort($array, 'customSort');
print_r($array);