Hello,
I am still looking for a way to phrase it properly (I'm not a native speaker...).
So I have this class SQL which implements the singleton pattern (for obvious reasons) and I also have this function, checkUsr(), which queries the database using one of SQL's methods.
Everything works fine as long as I don't call checkUsr() from within the SQL class. When I do so, the scripts just exits and a blank page is displayed - no errors are returned, no exception is thrown... What's happening? And how do I work around this problem?
EDIT:
class SQL
{
  public static function singleton()
  {
    static $instance;
    if(!isset($instance))
      $instance = new SQL;
    return $instance;
  }
  public function tryLoginAuthor( $login, $sha1 )
  {
    (...)
  }
}
function checkUsr()
{
    if (!isset($_SESSION['login']) || !isset($_SESSION['sha1']))
        throw new Exception('Not logged in', 1);
    $SQL = SQL::singleton();
    $res = $SQL->tryLoginAuthor($_SESSION['login'], $_SESSION['sha1']);
    if (!isset($res[0]))
      throw new Exception('Not logged in', 1);
}