decode

$obj->decode($octets [, $check]) - UTF-16/32 or UCS-2 octets to a character string.

The byte order comes from the object’s endian; with none (UTF-16, UTF-32) a leading BOM decides it and a missing one means big-endian. Surrogate pairs are combined; a lone or malformed surrogate, a surrogate in UCS-2 or UTF-32, and a non-character become U+FFFD - or croak with FB_CROAK, or warn with FB_WARN. A true CHECK without LEAVE_SRC leaves the undecoded tail in $octets.