illumos: manual page: charmap.7

CHARMAP(7) Standards, Environments, and Macros CHARMAP(7)

NAME

charmap - character set description file

DESCRIPTION

A character set description file or charmap defines characteristics for a
coded character set. Other information about the coded character set may
also be in the file. Coded character set character values are defined
using symbolic character names followed by character encoding values.

The character set description file provides:

o The capability to describe character set attributes (such as
collation order or character classes) independent of character
set encoding, and using only the characters in the portable
character set. This makes it possible to create generic
localedef(1) source files for all codesets that share the
portable character set.

o Standardized symbolic names for all characters in the portable
character set, making it possible to refer to any such
character regardless of encoding.

Symbolic Names

Each symbolic name is included in the file and is mapped to a unique
encoding value (except for those symbolic names that are shown with
identical glyphs). If the control characters commonly associated with
the symbolic names in the following table are supported by the
implementation, the symbolic names and their corresponding encoding
values are included in the file. Some of the encodings associated with
the symbolic names in this table may be the same as characters in the
portable character set table.

+----------------------------------------------+
|<ACK> <DC2> <ENQ> <FS> <IS4> <SOH> |
|<BEL> <DC3> <EOT> <GS> <LF> <STX> |
|<BS> <DC4> <ESC> <HT> <NAK> <SUB> |
|<CAN> <DEL> <ETB> <IS1> <RS> <SYN> |
|<CR> <DLE> <ETX> <IS2> <SI> <US> |
|<DC1> <EM> <FF> <IS3> <SO> <VT> |
+----------------------------------------------+

Declarations

The following declarations can precede the character definitions. Each
must consist of the symbol shown in the following list, starting in
column 1, including the surrounding brackets, followed by one or more
blank characters, followed by the value to be assigned to the symbol.

<code_set_name>
The name of the coded character set for which the
character set description file is defined.

<mb_cur_max>
The maximum number of bytes in a multi-byte character.
This defaults to 1.

<mb_cur_min>
An unsigned positive integer value that defines the
minimum number of bytes in a character for the encoded
character set.

<escape_char>
The escape character used to indicate that the
characters following will be interpreted in a special
way, as defined later in this section. This defaults
to backslash ('\'), which is the character glyph used
in all the following text and examples, unless
otherwise noted.

<comment_char>
The character that when placed in column 1 of a
charmap line, is used to indicate that the line is to
be ignored. The default character is the number sign
(#).

Format

The character set mapping definitions will be all the lines immediately
following an identifier line containing the string CHARMAP starting in
column 1, and preceding a trailer line containing the string END CHARMAP
starting in column 1. Empty lines and lines containing a <comment_char>
in the first column will be ignored. Each non-comment line of the
character set mapping definition, that is, between the CHARMAP and END
CHARMAP lines of the file), must be in either of two forms:

"%s %s %s\n",<symbolic-name>,<encoding>,<comments>

or

"%s...%s %s %s\n",<symbolic-name>,<symbolic-name>, <encoding>,\
<comments>

In the first format, the line in the character set mapping definition
defines a single symbolic name and a corresponding encoding. A character
following an escape character is interpreted as itself; for example, the
sequence "<\\\>>" represents the symbolic name "\>" enclosed between
angle brackets.

In the second format, the line in the character set mapping definition
defines a range of one or more symbolic names. In this form, the symbolic
names must consist of zero or more non-numeric characters, followed by
an integer formed by one or more decimal digits. The characters preceding
the integer must be identical in the two symbolic names, and the integer
formed by the digits in the second symbolic name must be equal to or
greater than the integer formed by the digits in the first name. This is
interpreted as a series of symbolic names formed from the common part and
each of the integers between the first and the second integer, inclusive.
As an example, <j0101>...<j0104> is interpreted as the symbolic names
<j0101>, <j0102>, <j0103>, and <j0104>, in that order.

A character set mapping definition line must exist for all symbolic names
and must define the coded character value that corresponds to the
character glyph indicated in the table, or the coded character value that
corresponds with the control character symbolic name. If the control
characters commonly associated with the symbolic names are supported by
the implementation, the symbolic name and the corresponding encoding
value must be included in the file. Additional unique symbolic names may
be included. A coded character value can be represented by more than one
symbolic name.

The encoding part is expressed as one (for single-byte character values)
or more concatenated decimal, octal or hexadecimal constants in the
following formats:

"%cd%d",<escape_char>,<decimal byte value>

"%cx%x",<escape_char>,<hexadecimal byte value>

"%c%o",<escape_char>,<octal byte value>

Decimal Constants

Decimal constants must be represented by two or three decimal digits,
preceded by the escape character and the lower-case letter d; for
example, \d05, \d97, or \d143. Hexadecimal constants must be represented
by two hexadecimal digits, preceded by the escape character and the
lower-case letter x; for example, \x05, \x61, or \x8f. Octal constants
must be represented by two or three octal digits, preceded by the escape
character; for example, \05, \141, or \217. In a portable charmap file,
each constant must represent an 8-bit byte. Implementations supporting
other byte sizes may allow constants to represent values larger than
those that can be represented in 8-bit bytes, and to allow additional
digits in constants. When constants are concatenated for multi-byte
character values, they must be of the same type, and interpreted in byte
order from first to last with the least significant byte of the multi-
byte character specified by the last constant.

Ranges of Symbolic Names

In lines defining ranges of symbolic names, the encoded value is the
value for the first symbolic name in the range (the symbolic name
preceding the ellipsis). Subsequent symbolic names defined by the range
will have encoding values in increasing order. Bytes are treated as
unsigned octets and carry is propagated between the bytes as necessary to
represent the range. However, because this causes a null byte in the
second or subsequent bytes of a character, such a declaration should not
be specified. For example, the line

<j0101>...<j0104> \d129\d254

is interpreted as:

<j0101> \d129\d254
<j0102> \d129\d255
<j0103> \d130\d00
<j0104> \d130\d01

The expanded declaration of the symbol <j0103> in the above example is an
invalid specification, because it contains a null byte in the second byte
of a character.

The comment is optional.

Width Specification

The following declarations can follow the character set mapping
definitions (after the "END CHARMAP" statement). Each consists of the
keyword shown in the following list, starting in column 1, followed by
the value(s) to be associated to the keyword, as defined below.

WIDTH
A non-negative integer value defining the column width
for the printable character in the coded character set
mapping definitions. Coded character set character
values are defined using symbolic character names
followed by column width values. Defining a character
with more than one WIDTH produces undefined results. The
END WIDTH keyword is used to terminate the WIDTH
definitions. Specifying the width of a non-printable
character in a WIDTH declaration produces undefined
results.

WIDTH_DEFAULT
A non-negative integer value defining the default column
width for any printable character not listed by one of
the WIDTH keywords. If no WIDTH_DEFAULT keyword is
included in the charmap, the default character width is
1.

Example:

After the "END CHARMAP" statement, a syntax for a width definition would
be:

WIDTH
<A> 1
<B> 1
<C>...<Z> 1
...
<fool>...<foon> 2
...
END WIDTH

In this example, the numerical code point values represented by the
symbols <A> and <B> are assigned a width of 1. The code point values < C>
to <Z> inclusive, that is, <C>, <D>, <E>, and so on, are also assigned a
width of 1. Using <A>...<Z> would have required fewer lines, but the
alternative was shown to demonstrate flexibility. The keyword
WIDTH_DEFAULT could have been added as appropriate.