implements_sample.php

<?php
interface ILogin {
  public function check_password(
                    $username,
                    $password,
                    $opts = array()
                  );
  public function do_login(
                    $username,
                    $password,
                    $opts = array()
                  );
  public function check_session(
                    $username
                  );
}

class MyOwnLoginClass implements ILogin {
  public function ckeck_password(
                    $username,
                    $password,
                    $opts = array()
                  ) {
  }

  public function do_login(
                    $username,
                    $password
                  ) {
  }
}

/*
 * OUTOUT:
 * 
 * PHP Fatal error:  Declaration of MyOwnLoginClass::do_login()
 *   must be compatible with that of ILogin::do_login()
 *   in /Users/yitsushi/a.php on line 8
 * 
 * Fatal error: Declaration of MyOwnLoginClass::do_login()
 *   must be compatible with that of ILogin::do_login()
 *   in /Users/yitsushi/a.php on line 8
 * 
 * if I fix the parameter error:
 * PHP Fatal error:  Class MyOwnLoginClass contains 2 abstract
 *   methods and must therefore be declared abstract
 *   or implement the remaining methods
 *   (ILogin::check_password, ILogin::check_session)
 *   in /Users/yitsushi/a.php on line 14
 * 
 * Fatal error: Class MyOwnLoginClass contains 2 abstract
 *   methods and must therefore be declared abstract
 *   or implement the remaining methods
 *   (ILogin::check_password, ILogin::check_session)
 *   in /Users/yitsushi/a.php on line 14
 *
 * I need a check_session() !!!!
 */