HTTP_POST_VARS not and array when used in a function?

Hey, Why doesn't HTTP_POST_VARS work inside functions? ---somefile.php - forms action --- function foo() {

      reset($HTTP_POST_VARS);
       while( list($key, $val) = each($HTTP_POST_VARS) ) {
               if ( $key != "Submit" xor $key != "x" xor  $key != "y" ) {
                $input[$key] = $val;
                }
      }
      return $input;

} $input = foo(); --- I thought the above would work but it returns the following error(s): ... value passed to reset is not an array or object ... ... value passed to each is not an array or object ... It seems that HTTP_POST_VARS does not like being called from inside functions, as the above will work if not inside the function, I thought that HTTP_POST_VARS was in the global scope (as of php 4.0.3 track-vars is always on) , so it should have no problem being called from anywhere? Does anyone know what gives? Regards, Joseph