.\" Copyright (c) 2002, 2003 Tim J. Robbins
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.\" $FreeBSD$
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.Dd August 10, 2003
.Dt GB18030 5
.Os
.Sh NAME
.Nm gb18030
.Nd "GB 18030 encoding method for Chinese text"
.Sh SYNOPSIS
.Nm ENCODING
.Qq GB18030
.Sh DESCRIPTION
The
.Nm GB18030
encoding implements GB 18030-2000, a PRC national standard for the encoding of
Chinese characters.
It is a superset of the older GB\ 2312-1980 and GBK encodings,
and incorporates Unicode's Unihan Extension A completely.
It also provides code space for all Unicode 3.0 code points.
.Pp
Multibyte characters in the
.Nm GB18030
encoding can be one byte, two bytes, or
four bytes long.
There are a total of over 1.5 million code positions.
.Pp
.No GB\ 11383-1981 Pq Tn ASCII
characters are represented by single bytes in the range 0x00 to 0x7F.
.Pp
Chinese characters are represented as either two bytes or four bytes.
Characters that are represented by two bytes begin with a byte in the range
0x81-0xFE and end with a byte either in the range 0x40-0x7E or 0x80-0xFE.
.Pp
Characters that are represented by four bytes begin with a byte in the range
0x81-0xFE, have a second byte in the range 0x30-0x39, a third byte in the range
0x81-0xFE and a fourth byte in the range 0x30-0x39.
.Sh SEE ALSO
.Xr euc 5 ,
.Xr gb2312 5 ,
.Xr gbk 5 ,
.Xr utf8 5
.Rs
.%T "Chinese National Standard GB 18030-2000: Information Technology -- Chinese ideograms coded character set for information interchange -- Extension for the basic set"
.%D "March 2000"
.Re
.Rs
.%Q "The Unicode Consortium"
.%T "The Unicode Standard, Version 3.0"
.%D "2000"
.Re
.Sh STANDARDS
The
.Nm GB18030
encoding is believed to be compatible with GB 18030-2000.