$filename = 'example.txt'; if (!is_readable($filename)) { setError("File is not readable"); } $error_message = error_get_last(); echo $error_message['message'];In this example, if the file `example.txt` is not readable, the `setError` function will be called and the error message "File is not readable" will be set. The `error_get_last` function is then called to retrieve the last error message and display it on the page. This function is part of the PHP core library and is not part of any package library.