(PHP 4 >= 4.2.0, PHP 5)
ibase_delete_user — Delete a user from a security database (only for IB6 or later)
$service_handle
   , string $user_name
   )
   PHP 4 uses server,
   dba_user_name and
   dba_user_password instead of
   service_handle parameter.
  
This function is currently not documented; only its argument list is available.
   Returns TRUE on success or FALSE on failure.