- var_dump: documentation ( source)
- base64_decode: documentation ( source)
<?php
function machine_forget(&$data) {
unset($data);
}
echo "normal\n";
$answer = 42;
var_dump((string)$answer);
machine_forget($answer);
var_dump((string)$answer);
echo "\n";
echo "magic\n";
// shhh no spoilers
eval(base64_decode('CmNsYXNzIHpvbWJpZQp7CiAgICBwcm90ZWN0ZWQgJHZhbDsKICAgIHB1YmxpYyBmdW5jdGlvbiBfX2NvbnN0cnVjdCgkdmFsKQogICAgewogICAgICAgICR0aGlzLT52YWwgPSAkdmFsOwogICAgfQoKICAgIHB1YmxpYyBmdW5jdGlvbiBfX2Rlc3RydWN0KCkKICAgIHsKICAgICAgICAkdGhpcy0+dmVzc2VsID0gJHRoaXM7CiAgICB9CgogICAgcHVibGljIGZ1bmN0aW9uIF9fdG9TdHJpbmcoKQogICAgewogICAgICAgIHJldHVybiAkdGhpcy0+dmFsOwogICAgfQp9CgokYW5zd2VyID0gbmV3IHpvbWJpZSgiNDIiKTsKJGFuc3dlci0+dmVzc2VsID0gJiRhbnN3ZXI7'));
var_dump((string)$answer);
machine_forget($answer);
var_dump((string)$answer);
// DID NOT FORGET
echo "\n";
echo "normal again\n";
$answer = 42;
var_dump((string)$answer);
machine_forget($answer);
var_dump((string)$answer);
// FORGOT