为什么php中是直接用$获取值而不是使用$_GET进行字符转义

<?
function my_addslashes($string, $force = 0) {
!defined('MAGIC_QUOTES_GPC') && define('MAGIC_QUOTES_GPC', get_magic_quotes_gpc());
if(!MAGIC_QUOTES_GPC || $force) {
if(is_array($string)) {
foreach($string as $key => $val) {
$string[$key] = my_addslashes($val, $force);
}
} else {
$string = addslashes($string);
}
}
return $string;
}
foreach(array('_COOKIE', '_POST', '_GET') as $_request) {
foreach($$_request as $_key => $_value) {
$_key{0} != '_' && $$_key = my_addslashes($_value);
}
}
echo $urls;
?>