eucset - Sets and gets EUC code widths for the terminal
Displays the current settings of the EUC character widths
for the terminal
The eucset command sets or gets the encoding and display
widths of the Extended UNIX Code (EUC) characters processed
by the current input terminal. EUC is an encoding
method for code sets composed of single or multiple bytes.
It permits applications and the terminal hardware to use
the 7-bit US ASCII code and up to three single- or multibyte
code sets simultaneously.
If you use the eucset command to set EUC character widths,
but do not specify the cswidth argument, 7-bit U.S. ASCII
is applied as a default code set. You must use the command
to specify any other EUC code sets, whether they are single-byte
EUC Code Set Classes [Toc] [Back]
EUC divides code sets into four classes. Each code set
class has two characteristics: the number of bytes for
encoding the characters in the class, and the number of
display columns to display the characters in the class.
All characters within a class possess the same characteristics.
Class 0 consists of all 7-bit, single-byte ASCII characters.
The most-significant bit of each of these characters
is 0 (zero). Characters in class 0 require one byte
for encoding, and occupy one display column. These values
are fixed for class 0 (zero). The 7-bit US ASCII code is
the primary EUC code set, which is available to users
without direct specification.
A class 1 code set is a supplementary EUC code set. Class
1 characters have an initial byte whose most-significant
bit is 1. If character classes 2 or 3 are to be used,
this initial byte must not be the SS2 or SS3 character, as
these designate character classes 2 and 3. Characters in
class 1 may require more than 1 byte for encoding, and may
require more than 1 display column. The eucset command
must be used to set the characteristics for code set class
Class 2 and 3 code sets are supplementary EUC code sets.
Characters in these classes have an initial byte of SS2 or
SS3, respectively. They require more than 1 byte for
encoding, and may require more than 1 display column. The
eucset command must be used to set the characteristics for
code set classes 2 and 3.
The cswidth argument in the eucset command line is a
character string that describes the character widths for
code set classes 1 through 3. The string is of the following
format: X1[:Y1], X2[:Y2], X3[:Y3]
The value X1 is the number of bytes required to encode a
character in code set class 1. Y1 is the number of display
columns needed to display characters in this class.
X2 is the number of bytes required to encode a character
in code set class 2, not counting the SS2 byte, and Y2 is
the number of display columns for code set class 2 characters.
X3 is the number of bytes needed to encode characters
in code set class 3, not counting the SS3 byte, and
Y3 is the number of display columns required for these
characters. The values for the column widths can be omitted
if they are equal to the number of encoding bytes. If
the encoding value of any of the EUC code sets is set to 0
(zero), this indicates that the code set does not exist.
If no cswidth argument is supplied, the eucset command
uses the value of the CSWIDTH environment variable. If
this variable is not present, the default string
1:1,0:0,0:0 is substituted. This default string designates
that the environment uses a single-byte EUC code set that
has characters in the EUC code set class 1 format. If the
environment uses a multibyte EUC code set in the code set
class 1 format, single- or multibyte EUC code sets in the
code set class 2 or 3 format, or both, the default setting
cannot be used.
Your standard input is not an interactive terminal. The
maximum character width of 8 was exceeded.
To display the encoding and display widths for the EUC
code set classes 1-3 in your environment, enter: eucset -p
To change the current settings of the encoding and display
widths for the EUC characters in code set classes 1 and 2
to 2 bytes each, enter: eucset 2:2,2:2,0:0
or eucset 2,2,0
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