How can I get my current location (threadid) in a plugin?

[acanuck]

I'm trying to get my current threadid location in a plugin.

PHP Code:

$vbulletin->db->escape_string($vbulletin->input->clean_gpc('r', 't', TYPE_UINT)) 


supposedly does that but when I call it I get the error:

Warning: Cannot modify header information - headers already sent by (output started at .../includes/class_bootstrap.php(283) : eval()'d code:178) in .../includes/functions.php on line 3736

Warning: Cannot modify header information - headers already sent by (output started at .../includes/class_bootstrap.php(283) : eval()'d code:178) in .../includes/functions.php on line 3737

So does this mean I can only call it once?
If so how do I get the current threadid?