CHARMAP(5)CHARMAP(5)NAMEcharmap - 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 charac‐
ter set encoding, and using only the characters in the por‐
table 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 porta‐
ble 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 imple‐
mentation, 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 por‐
table 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 charac‐
ter. 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 char‐
acters 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 <com‐
ment_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 charac‐
ter following an escape character is interpreted as itself; for exam‐
ple, 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 sym‐
bolic names must consist of zero or more non-numeric characters, fol‐
lowed by an integer formed by one or more decimal digits. The charac‐
ters 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 inter‐
preted 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 con‐
trol characters commonly associated with the symbolic names are sup‐
ported 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 val‐
ues) 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 exam‐
ple, \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 pre‐
ceding 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 defini‐
tions (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 fol‐
lowed 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 col‐
umn 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.
SEE ALSOlocale(1), localedef(1), nl_langinfo(3C), extensions(5), locale(5)
Dec 1, 2003 CHARMAP(5)
