mixed I18Nv2_Locale::setDateFormat ( 
    int $format
     , bool $custom
      = false
    
   )
Set the date format to use.
Either a I18Nv2_DATETIME constant or a custom date format.
$format
     a I18Nv2_DATETIME constant
$custom
     whether to use a defined custom format
Returns TRUE on success, PEAR_Error on failure.
This function can not be called statically.