(php) if condition not working

Question

I am going crazy here. The following simple if-condition does not produce the right output.

$xxx = 1;
if($xxx == 1)
    define('DEBUG', true);
else
    define('DEBUG', false);
var_dump($xxx);
var_dump(DEBUG);
die();

Output:

int(1)
bool(false)

I see absolutely no reason why the DEBUG constant is not being set to true. PHP's type juggling should allow this if-statement. And even if I put an intval in front of the variable, it still produces false as output.

Edit 2: I copied the exact code from above into a new file and it produces the expected output. So I don't know what is going on...

Answer 1

var_dump($vbulletin->userinfo['userid']);

Output :

string(1)

Your string length is one, and it seems to be empty (a space ?).