It seems that it is not possible to reference the $_GET, $_POST, etc using
a variable as in (A) :
$var_get = '_GET';
$local_get = $$var_get;

$var_http_get = 'HTTP_GET_VARS';
$local_http_get = $$var_http_get;

Now if the requested url contains &something=12

print $local_http_get['something'] . '*';     // print the string '12*'
print $local_get['something'] . '*';   // print the string '*'

But if (B) :
$local_good=&$_GET;
$var_good = 'local_good';
$var_get = $$var_good;
print $local_get['something'] . '*';   // print the string '12*'

Would it be a problem trying to reference a variable which name starts
with an underscore ?

I use this kind of syntax to check if something not allowed exists in the url,
using an array like $to_check = array( '_GET', '_POST' );

Anyway, as it's possible to use an alternative syntax (B), it is
not a __big__ problem, after all !

Keep on with a so nice job, I am still amazed about the power and speed
of Php, after more than 2 years using it, in a production environment.

Thanks a lot, and have a nice day.