How long can a PHP function name be?

func.php

<?php

// How long can a function name in PHP get?
$alpha = 'abcdefghijklmnopqrstuvwxyz';

// Note: PHP will run out of memory if you make this range too large
for ($i = 1; $i <= 10000; $i++) {
    $name = str_pad('', $i, $alpha);
    $count = strlen($name);

    eval('function ' . $name . "() { echo '{$count}' . PHP_EOL; }");

    $name();
}

echo "Final name:\n{$name}\n";