What is the error message "Fatal error: Uncaught Error: Call to undefined function variant_int()" in PHP 8.1 indicating?

The error message "Fatal error: Uncaught Error: Call to undefined function variant_int()" in PHP 8.1 indicates that the function variant_int() is not defined or available in the current PHP environment. This function is part of the Variant extension, which is not enabled by default in PHP 8.1. To solve this issue, you need to enable the Variant extension in your PHP configuration.

// Enable the Variant extension in PHP configuration
// Add the following line to your php.ini file
extension=php_variant.dll