(PHP 5.5.0, PECL >= 3.0.0a1)
$reason
   , string $source
   , string $codePoint
   , integer &$error
   )$str
   , string $toEncoding
   , string $fromEncoding
   [, array $options
  ] )UConverter::REASON_UNASSIGNED
     UConverter::REASON_ILLEGAL
     UConverter::REASON_IRREGULAR
     UConverter::REASON_RESET
     UConverter::REASON_CLOSE
     UConverter::REASON_CLONE
     UConverter::UNSUPPORTED_CONVERTER
     UConverter::SBCS
     UConverter::DBCS
     UConverter::MBCS
     UConverter::LATIN_1
     UConverter::UTF8
     UConverter::UTF16_BigEndian
     UConverter::UTF16_LittleEndian
     UConverter::UTF32_BigEndian
     UConverter::UTF32_LittleEndian
     UConverter::EBCDIC_STATEFUL
     UConverter::ISO_2022
     UConverter::LMBCS_1
     UConverter::LMBCS_2
     UConverter::LMBCS_3
     UConverter::LMBCS_4
     UConverter::LMBCS_5
     UConverter::LMBCS_6
     UConverter::LMBCS_8
     UConverter::LMBCS_11
     UConverter::LMBCS_16
     UConverter::LMBCS_17
     UConverter::LMBCS_18
     UConverter::LMBCS_19
     UConverter::LMBCS_LAST
     UConverter::HZ
     UConverter::SCSU
     UConverter::ISCII
     UConverter::US_ASCII
     UConverter::UTF7
     UConverter::BOCU1
     UConverter::UTF16
     UConverter::UTF32
     UConverter::CESU8
     UConverter::IMAP_MAILBOX